If they are really allergic to rice, then it will not tolerate COD-HY/FOD-HY. However, often an allergy to rice is assumed based on a positive IgE test. It should be noted that it has been shown that IgE testing for food allergen is not very reliable (Hardy et al 2014), meaning that a positive IgE level to rice does not automatically mean that the dog will show adverse effects when eating rice.

If the dog is however really allergic to rice, then one of the rice-free diets of the SPECIFIC range can be used: CPD, CXD, CGD, CED-DM, CIW-LF, F/C-IN-W, F/C-IN-L, C-BIO-W with beef, C-BIO-W with fish

For cats with real rice allergy the following SPECIFIC diets can be used: FED-DM, FKD, FRD, FXW, FEW-DM, FRW, F/C-IN-W, F/C-IN-L,F-BIO-W with chicken, F-BIO-W with fish

Reference:

Hardy JI et al. Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories. Vet Dermatol 2014: 25 : 447-e70

In the product book, it is indicated that SPECIFIC CDD-HY or FDD-HY Food Allergen Management or COD-HY, COW-HY, FOD-HY, FOW-HY Allergen Management Plus can be used as an elimination diet. However, it should be stressed that for diagnosis of adverse food reactions an elimination trial with a home-made diet followed by provocation is still regarded as ‘golden standard’.
However, in practice veterinarians often have the problem that owners do not want to cook for their pet, or that they are just not capable of doing so. In these practical situations where the use of a home-made diet is not feasible, SPECIFIC CDD-HY or FDD-HY Food Allergen Management or Allergen Management Plus diets can be used as elimination diet in order to improve owner’s compliance.

Food allergy can occur at any age. In dogs a range of 4 months to 14 years of age has been reported. However, food allergy is most often diagnosed in young dogs. In 35-50% of the food allergic dogs, first symptoms appeared before the age of 1 year. In cats, signs of food allergy can show from the age of 6 months of 11 years. In almost 40% of the cases, clinical symptoms are seen before the age of 2 years.

Yes, as long as the dog shows allergic reactions towards allergens which cannot be avoided, SPECIFIC Allergen Management Plus or SPECIFIC Skin Function Support can be used to dampen the inflammatory response.

Within the SPECIFIC range CDD Food Allergen Management is recommended because it doesn’t contain wheat and the liver function of the dog with hepatic failure is supported by the diet’s  moderate protein level (to reduce hyperammonemia and hepatic encephalopathy), its high protein digestibility, extra zinc (vs recommendation), added vit C and low purine content ( as some liver problems may increase the risk on purine uroliths)

The diet is not as low in sodium and copper as CKD, but still not very high

The composition of the optimal hypoallergenic diet for an individual dog will depend on the dog’s dietary history of dogs and/or its known food allergens.

If the dog would tolerate both CDD-HY and CDD Food Allergy Management, there is in theory a preference for CDD-HY, since the chance that dog develops a new allergy towards the components of its hypoallergenic diet are smaller on CDD-HY: the salmon protein in hydrolysed and will therefore be too small to provoke an allergic reaction, also in future.

Fatty acids can have an effect on coagulation as being used as precursor for the production of eicosanoids which can effect coagulation. Aggregation of platelets is affected by thromboxanes: TXA2 is produced from arachidonic acid has a strong pro-aggregation effect. TXA3 is produced from EPA and is only very weak in inducing aggregation of platelets.

In literature decreased platelet aggregation was found in humans at high EPA/DHA intakes. However in cats results were mixed. In a study where they used levels of EPA and DHA which were more than twice as high than the highest levels which are present in SPECIFIC Skin Function Support,  there was no effect (Bright et al. 1994). Also in studies with dogs, only very small effects (no clinical relevance) or no effects were found.

We have evaluated the effect of SPECIFIC COD on bleeding time in a study with laboratory dogs which were fed COD for a period of 12 weeks. Bleeding time was not affected by feeding COD. Also in the clinical trial on the effect of COD on atopic dogs, bleeding time of the dogs was measured at the start of the study and after being on the diet for 10 weeks. COD did not increase bleeding time. Even though we did not find any adverse effect of COD on bleeding time in dogs, we indicated at the ‘contraindications’ for COD to be cautious in dogs with coagulation problems. This is just done to be sure, not because we ever found any adverse effects.

Eicosanoids play a key-role in inflammatory reactions. The production of eicosanoids can be affected by the level and type of dietary fatty acids. The high levels of EPA and GLA in SPECIFIC COD and COD-HY will induce the production of beneficial eicosanoids, which can help to dampen the body’s natural anti-inflammatory response.

The production of eicosanoids can also be affected by the use of drugs like corticosteroids and NSAID’s (non-steroid anti-inflammatory drugs as aspirin and ibuprofen). Corticosteroids inhibit the activity of phospholipase A2, the enzyme responsible for the release of arachidonic acid from the cell membrane, yielding free arachidonic acid what can be metabolised into pro-inflammatory eicosanoids. NSAID’s inhibit the activity of cyclo-oxygenase and thereby the production of serie-2 prostaglandines from arachidonic acid.

Thus, the result of EPA and GLA, but also of corticosteroids and NSAID’s is a reduced production of ‘aggressive’ pro-inflammatory eicosanoids from arachidonic acid. In literature has been described that fatty acids and drugs like corticosteroids and anti-histamines work synergistic: the level of corticosteroids or anti-histamines required to suppress clinical signs in atopic dogs can be reduced by the use of EPA and GLA (Saevik et al. 2004) .

In literature there is no univocal information on the incidence of atopy and food allergy. Reported incidence can be affected by several factors like region, type of clinic and diagnostic criteria. Generally atopy is regarded as the second most common cause of canine pruritus, after flea allergy. It has been estimated that 3-15% of the dog population has atopy. Food allergy is the third most common occurring skin allergy, accounting for 1% of all skin diseases in dogs and 10% of all allergic skin diseases in dogs. There is not much information on the incidence in cats.

Pets with food allergy, which are without clinical symptoms on a certain hypoallergenic diet and are switched to another hypoallergenic diet, may show a relapse of clinical symptoms within a period of 2-3 weeks.

In pets currently suffering from symptoms of food allergy, it may take up to 6-10 weeks, before a clear improvement is seen when fed a suitable hypoallergenic diet (especially in case of dermatological clinical signs; gastrointestinal signs of adverse food reactions tend to improve faster). For this reason it is recommended that and elimination trial is performed for a period of at least 8 weeks (Olivry et al 2015).

The beneficial effect of SPECIFIC COD Skin Function Support on skin and coat condition can be ascribed to the increased supply of nutrients like special fatty acids, vitamin A, E, Zn and selenium to the skin and the production of beneficial eicosanoids. For the production of ‘good’ eicosanoids, it is a prerequisite that fatty acids are well absorbed and incorporated in cell membranes. In our studies we found that it will take several weeks before a high, stable level of EPA can be found in the skin. Also in literature, it has been described that it can take several weeks before there is a significant change in eicosanoid production and severity of clinical signs. We therefore advise to use SPECIFIC COD  Skin Function Support for a period of at least 6-8 weeks before the full beneficial effect on skin and coat condition is visible.

It is known that allergic pets are at a higher risk of developing other hypersensitivities. It is therefore quite common that pets are allergic to more than one allergen and that they suffer from a combination of allergies. It has been reported that 20-30% of the cases with food allergy have concurrent atopy or flea allergy. In some studies with dogs with food allergy or atopy even up to 50% suffered from both atopy and food allergy.

Yes, a dog or cat can be fed on high omega-3 diets such as SPECIFIC Allergen Management Plus or Skin Function Support throughout its life. In experimental studies and in a clinical trial with dogs fed on SPECIFIC COD we did not find any adverse effects regarding bleeding time, general blood chemistry, anti-oxidant status or diarrhoea. Despite this finding we do not recommend the diet for dogs which are immune-deficient, or have coagulation abnormalities.

Omega-3 fatty acids have a beneficial effect on skin and coat function, function of the immune system, mobility of joints and kidney function. The intake of high levels of omega-3 fatty acids is especially beneficial in dogs with hyperresponsive inflammatory reactions, because the fatty acids can dampen the inflammatory response. This is for instance important in atopic dogs with an allergic reaction towards allergens, which cannot be avoided.

Yes, it is possible to show an adverse reaction towards sources of omega-3 and omega-6 fatty acids (such as fats and oils). Allergenicity of edible oils and fats is related to the presence of residual protein. It is suggested that in crude edible oils the protein content is in the order of 0.1-0.3 mg/ml; in refined oils this level is reduced about 100-fold. Studies have shown that crude oil can provoke allergic reactions in sensitive allergic individuals; it is assumed that refined oils do not represent a risk of provoking allergic reactions in the majority of allergic individuals.

The types of fat used in hypoallergenic diets should be considered as types of fats and refined oil might contain traces of potential protein allergens.

The pork fat which is coated on the dry SPECIFIC hypoallergenic diets has been shown by means of PCR analysis to be free of pork protein and therefore will not induce an adverse reaction in pets allergic to pork.

The fish oil which is used in hypoallergenic SPECIFIC diets is also tested by PCR-analysis and it free of fish protein, and will therefore not induce an adverse reaction in pets with an allergy towards fish.

Food allergy can only be diagnosed by means of elimination trial, there are no other reliable tests. Thus, in order to set the right diagnosis, the execution of an elimination trial is essential. However, sometimes owners are not willing or capable to perform an elimination trial. In these cases, it is recommend to feed Food Allergen Management or Allergen Management Plus and to evaluate the pet’s response to the diet.
If the pet improves on the hypoallergenic SPECIFIC diet, a diagnosis of food allergy can only be made after relapse of clinical signs after a challenge with the pet’s original diet.

Food allergy can only be diagnosed by means of elimination trial, there are no other reliable tests. Thus, order to set the right diagnosis, the execution of an elimination trial is essential. However, sometimes owners are not willing or capable to perform an elimination trial. In these cases, it is recommend to Food Allergy Management and to evaluate the pet’s response to the diet.

For diagnosis of adverse food reactions an elimination trial with a home-made diet followed by provocation is regarded as ‘golden standard’. In practical situations, the use of a home-made eliminations diet is not always feasible. Preparation of home-made diets can be labour intensive and owners may not be willing to prepare a home-made diet. Furthermore, home-made diets are not complete in all nutrients and are therefore not recommended for suited for young growing pets. In these situations SPECIFIC Food Allergen Management or Allergen Management Plus with hydrolysed salmon are recommended as elimination diet in order to increase compliance of the owner and to better meet the nutrient requirement of growing pets.

The aim of using an elimination diet is to set the diagnosis of food allergy. Food allergy can only be diagnosed if clinical symptoms disappear when fed on an elimination diet and relapse after provocation with the habitual diet. The suitability of an elimination diet depends on the raw materials which are used in the diet and the raw materials to which the dog/cat has been exposed to during its life (as an allergy can only develop after prior exposure to an allergen).  
The raw materials which are used in  SPECIFIC CDD-HY/FDD-HY Food Allergen Management are almost identical to those used in SPECIFIC CΩD-HY/FOD-HY Allergen Management Plus: there is only a difference in the fat sources in the diet: CDD-HY/FDD-HY Food Allergen Management and COD-HY/FOD-HY Allergen Management Plus both contain pork fat and fish oil, but the inclusion levels are different. CDD-HY/FDD-HY Food Allergen Management contains a much larger amount of pork fat and a small amount of fish oil, whereas COD-HY/FOD-HY Allergen Management Plus contains a large amount of fish oil and a much lower amount of pork fat. The only difference in type of raw materials is that COD-HY/FOD-HY Allergen Management Plus contains borage oil, which is not present in CDD-HY/FDD-HY. Because CDD-HY/FDD-HY contains one  raw material less it may therefore be preferred, however the risk of an allergic reaction towards borage oil is very low.

SPECIFIC CΩD-HY/FOD-HY Allergen Management Plus is a kind of ‘all-in-one diet’, which can be beneficial  in all types of allergic dermatitis food allergy, atopy, flea allergy and any combination of allergies. SPECIFIC  Allergen Management Plus diets are especially recommended in case the veterinarian wants to have most chance to get rid of the clinical signs, without initially setting the exact diagnosis (’black-box approach’)

No, there is no problem to feed these dry hypoallergenic diets since PCR-analyses of the pork fat has shown that the fat does not contain any traces of pork protein. Allergic reactions are in fact towards proteins and since there is no pork protein present in the fat, it is safe to feed these diets to pets with an allergy towards pork.

A primary feature of evening primrose oil is its content of GLA, gamma-linolenic acid. Just as for the omega-3 fatty acids EPA and DHA it has been shown that GLA can be used as a precursor for metabolization of beneficial eicosanoids than can help to support the body’s natural anti-inflammatory response. Besides the high levels of EPA and DHA in SPECIFIC Allergen Management Plus and Skin Function Support, these diets also contain borage oil as a source of GLA.  When using SPECIFIC Allergen Management Plus or Skin Function Support it is thus not necessary to add supplements as evening primrose oil.

There is no general consensus on the exact maximum molecule weight to guarantee absence of allergenicity.

Immunological reactions to food components are usually against glycoproteins, commonly ranging in size from 10.000 to 70.000 Dalton (Cave 2006, Sampson 1993). In some publications even higher minimum molecule weights of food allergens as 14.000 or 18.000 Dalton are stated (Puigdemont et al. 2006, Biourge et al. 2004). In theory, hydrolysation of protein into small peptide fragments will reduce its allergenicity, because offending epitopes will be broken down and will not bind to the IgE receptors on the mast cell surface. Furthermore, mast cell degranulation will only take place after cross-linking of 2 or more IgE molecules are bound to IgE receptors on the mast cell. This means that the allergen must be large enough to bind to 2 IgE receptors. Most publications indicate that a molecule must be at least as big as 10.000 Dalton in order to be able to bind to 2 IgE receptors (Cave 2006).

From a theoretical point of view: the smaller the molecule weight, the less likely that the allergenitic epitope is still intact. However, if the molecule size is very small, the protein hydrolysate might still cause an allergic reaction. Extensively hydrolysed cow milk formulas (with molecule weight of ca. 1500 Dalton) have been successfully applied in the feeding of babies with cow milk allergy. However, even on these extensively hydrolysed protein sources, about 5-20% of the food allergic infants relapse. This can be explained by the presence of minor traces of intact protein in the hydrolysate. It has also been hypothesized that very small peptides, which cannot activate IgE molecules themselves, might still bind to other components and act as haptens, causing an allergic reaction. Adverse food reactions which are not IgE-mediated (thus others than immunological type I reactions) are not necessarily expected to improve after protein hydrolysation.

Extensive hydrolysation to hydrolysates with lower molecules weights might also introduce some side-effects like reduced palatability and increased osmolality with associated loose stools or diarrhoea.

There are not many studies on the efficacy of protein hydrolysates in dogs with well diagnosed food allergy. However, most of them relate to the efficacy of hydrolysates with a maximum molecule weight of 10.000 or 12.200 Dalton. Studies with soy hydrolysates (MW< 12.200 Dalton) in dogs with induced soy hypersensitivity showed a reduced response to hydrolysed soy (in contrast to intact soy) (Beale & Laflamme 2001, Puigdemont et al. 2006). Another study showed that 90% of dogs with food allergy could successfully be maintained on a commercial hypoallergenic diet based on soy hydrolysate with a maximum molecule weight of 10.000 Dalton (Biourge et al. 2004).

Presence of fleas or other parasites, infections with bacteria or yeasts, exposure to allergens, dry skin or stress will all stimulate itching. A food allergic pet or an atopic pet could have concurrent allergies and can best be fed on SPECIFIC Allergen Management Plus, if it cannot be totally controlled on another diet. Flea control, regular brushing, shampooing and avoidance of allergens can contribute to reduce the degree of itching. Immediate treatment of secondary infections can prevent deterioration of clinical signs. If needed, medication can be used to reduce pruritus.

Dechra offers a complete range of pharma and care products which can help to prevent or reduce clinical signs in pet with allergic dermatitis.

Taking into account the presence of food allergy and calcium oxalate urolithiasis the hypoallergenic SPECIFIC CDD Food Allergen Management would be the best option for this dog as the reduced protein level in the diet and the induction of a higher urinary pH will reduce the risk on calcium oxalate (a reduced protein level will reduce the supply of amino acids glycine which can be metabolised into oxalate). For further reduction on the risk on recurrence of Ca-ox (which we know is an issue even on an ‘anti-oxalate diet’), it is recommended to promote the water intake of the dog by adding extra hand-warm water to the diet (feeding as a ‘diner’ type of diet).

The basic composition of SPECIFIC hydrolysed diets is identical (hydrolysed salmon and rice), except for the type and amount of fat sources which have been used. The dry hydrolysed diets, all contain  pork fat and fish oil oil (with Allergen Management Plus having higher levels of fish oil in order to have increased levels of EPA and DHA, fatty acids which can yield eicosanoids that can help to support the body’s natural anti-inflammatory response). The wet Allergen Management Plus diets contain sunflower oil and high levels of fish oil. All Allergen Management Plus diets also contain borage oil, a source of GLA, a fatty acid which can also support the body’s natural anti-inflammatory response.  

Because the hydrolysed diets have similar basic compositions (hydrolysed salmon and rice), food allergic pets can easily be switched between wet and dry versions of  hydrolysed Food Allergen Management and Allergen Management Plus, depending on the preference for wet or dry diets and/or the need for extra fatty acids.

SPECIFIC Skin Function Support and Allergen Management Plus  contain a very high level of EPA. Several studies have shown that this high level of EPA is effective in the control of atopic dermatitis in dogs and has beneficial effects on clinical conditions like poor coat condition, cancer, arthritis, colitis ect. The daily intake of  EPA is much higher when feeding Skin Function Support or Allergen Management Plus in comparison to the amount of EPA which is delivered by fatty acids supplements.

SPECIFIC Skin Function Support and Allergen Management Plus  also contain increased levels of skin-related nutrients like Zn, vitamin A and vitamins of the B-complex and selenium. These nutrients support optimal skin and coat condition.

SPECIFIC  Skin Function Support and Allergen Management Plus are complete, balanced diets with increased levels of EPA, GLA and skin-related nutrients and a n-3:n-6 ratio of 1:1. When fatty acids supplements are added to a pet’s regular diet,  , the n-3:n-6 ratio of the total intake of the pet (diet + supplement) will mainly be determined by the fatty acid composition of the pet’s diet (which generally has an abundance of n-6 fatty acids like linoleic acid) and will remain close to 1:10.

When supplements are  given in addition to a habitual diet  the supplement’s dosage is adjusted according to the weight of the dog. However, often there  are only 3 dosage levels indicated . Feeding complete diets with very high levels of EPA, like SPECIFIC Skin Function Support and Allergen Management Plus assures a tailored dosage to any weight of the dog as the fatty acid composition is balanced to the energy content in the diet.

Many fatty acid supplements  recommend the same dosage to all dogs weighing more than 25 kg. The consequence is that the more the dog weighs over 25 kg, the lower the contribution  of fatty acids from fatty acid supplements  to the total fatty acid intake  of the dog; these large dogs may not get enough fatty acids to see an effect.

It is more convenient to use a diet that provides all beneficial fatty acids and skin-related nutrients (SPECIFIC Skin Function Support and Allergen Management Plus  ), than adding a separate fatty acid supplement to a regular diet. If very large amounts of fatty acid supplements or oils are added to a regular diet, this also adds a lot of extra energy to the pet’s daily intake, with the risk of obesity and dilution of the nutrient intake (on an energy basis), which may put the pet at risk for some nutrient deficiencies.

The hydrolysed salmon was first of all selected on having a molecule weight below 10.000 Dalton (considered to be small enough to prevent allergic reactions).

Further arguments were the high protein quality (good amino acid profile and high digestibility), the freshness of the protein source, the high quality control and traceability of Norwegian salmon. Also the fact that salmon is not of vegetable origin (in contrast to soy and relevant for cats) and less commonly used as raw material in pet food as other commercially available protein hydrolysates (such as chicken-, soy- and egg hydrolysate) were extra arguments to select the hydrolysed salmon as raw materials for the new SPECIFIC hypoallergenic diets. Furthermore fish is a sustainable protein source and fits well in the image and positioning of SPECIFIC.

Intact  salmon protein can be considered as a rather novel raw material in hypoallergenic diets for pets ; however there are commercial diets which contain salmon (e.g. wet cat diets in supermarkets; also in some of our wet SPECIFIC cat diets we use salmon as ingredient). For this reason we prefer to use hydrolysed instead of intact salmon protein in our new hydrolysed diets.

SPECIFIC CDD, CDW and FDW Food Allergen Management are only suited for adult dogs/cats, but SPECIFIC CDD-HY, FDD-HY Food Allergen Management and COD-HY, COW-HY, FOD-HY an FOW-HY Allergen Management Plus diets are specially formulated so that they also meet the nutrient requirements of growing dogs and cats and are thus also suited for puppies and kittens.   

For management of pancreatitis it is generally advised to avoid too much fat and protein in the diet to prevent stimulation of the pancreas.

Guidelines are* :

FOR CATS Fat: 10-15% on DMB and protein between 30-45% DMB  (DMB=dry matter basis)

FOR DOGS Fat: 10-15% on DMB and protein between 15-30% DMB for dogs

In addition: fat < 10% in case of concurrent hyperlipidemia or severe obesity.

Suitable SPECIFIC diets for cats with pancreatitis:

The general recommendation for adult cats with pancreatitis is FDD-HY, FΩD-HY and FXD and for juvenile cats FDD-HY, FΩD-HY and FND

Note: FRD is suited for elderly kittens, if they are able to eat sufficient energy from FRD Note: FDD-HY and FOD-HY are at respectively 29.5 and 29.7% protein, and FQD-F at 15.2% fat which is also acceptable

(FID and FIW are too high in fat)

The presence of other complications will have an impact on the dietary recommendation

For cats with pancreatitis and hyperlipidaemia  FΩD-HY may be first choice as the high level of n-3 may help to reduce the triglycerides and/or cholesterol levels, whilst FRD, with even lower fat levels, is also suitable.

For cats with pancreatitis and (risk on) diabetes mellitus FED-DM is first choice (the protein level of FED-DM is higher at 55% DM, but due to the low carbohydrate level and reduce fat level it is recommended to support cats with DM and pancreatitis).

For cats with pancreatitis and obesity FRD and FRW are recommended.

For cats with concurrent struvite problems: FXD or FCD-L is a good choice.

Suitable SPECIFIC diets for dogs with pancreatitis:

The general recommendation for adult dogs  with pancreatitis is CID-LF, CIW-LF, CDD-HY and CΩW-HY and for juvenile dogs CPD-XL, CDD-HY and CΩW-HY

In case of concurrent hyperlipidaemia, CID-LF and CIW-LF would be the first choice as the high level of n-3 may help to reduce the triglycerides and/or cholesterol level although CRD-2 and  CGD, with lowfat levels, and CΩW-HY, with high level of n-3, will also be suitable.

For dogs with pancreatitis and (risk on) diabetes mellitus; CED-DM and CRD-2 are first choice (CED-DM is slightly higher in protein than guideline, but due to low carbohydrate recommended for dogs with pancreatitis and DM)

For dogs with pancreatitis and obesity CID-LF, CIW-LF are first choice although CRD-2 is also suitable

For dogs with pancreatitis and IBD, where food allergy may also play a role CID-LF and/or CIW-LF are recommended.

There is an increasing knowledge on the beneficial effect of n-3 fatty acids on a variety of clinical conditions. This knowledge is derived from studies in humans, laboratory animals and sometimes also cats or dogs. 

In a rat model of colitis, addition of 8% fish oil to the diet reduced the severity of clinical symptoms and shortened the course of the colonic disease (Vilaseca et al.1990). In double-blinded, placebo-controlled studies with human patients with ulcerative colitis, long-term supplementation with fish oil (300-450 mg EPA/MJ) reduced the required dose of corticosteroids (Hawthorne et al. 1992) and also reduced the level of the inflammatory mediator LBT4 and improved the histological appearance of the colon (Stenson et al. 1992).

For pets with IBD it is recommended to feed a hypoallergenic diet, since it is expected that there might be a food-allergic component involved in the aetiology of IBD. Since also omega-3 fatty acids have proven to be effective in reducing clinical signs of colitis / inflammatory reactions in the GI-tract, SPECIFIC Allergen Management Plus is recommended for pets with IBD, due to its hypoallergenic composition and uniquely high level of EPA & DHA.

Beta-1,3/1,6-glucans are naturally occurring glucans found in the cell wall of fungi and yeast (glucans are carbohydrate polymers consisting of a chain of glucose molecules). The beta-1,3/1,6-glucan molecule has a long main chain of beta-1,3- linked glucose molecules with side chains composed of beta-1,3-linked glucose molecules. Beta-1,3/1,6-glucans have a high ability to enhance the immune system.

White blood cells, which are in the front line of the immune defence, have receptors which can bind to invading pathogens. On their surface they also have receptors to bind to beta-1,3/1,6-glucans. Binding of beta-1,3/1,6-glucans to the specific receptor induces the activation of the macrophage, enhancing the non-specific immune system. However, binding of beta-1,3/1,6-glucans also stimulates the macrophage to produce ‘alarm signals’ (such as cytokines) that alert the cells of the specific immune system (B and T cells). This leads to a higher immune status and higher production of immunoglobulins.

Studies  have shown that oral supplementation with beta-1,3/1,6-glucans reduced plasma concentrations of the pro-inflammatory cytokines IL-6 and TNF-alpha and increased the concentration of the anti-inflammatory cytokine IL-10. In this way, beta-1,3/1,6-glucans can have a damping effect on inflammatory reactions.

Thus, supplementation with beta-1,3/1,6-glucans can have beneficial health effects through two modes of action; it can lead to an enhanced immune status and it affect the body’s natural inflammatory response.

Supplementation with beta-1,3/1,6-glucans increased the levels of antibodies after vaccination and improved the resistance to several infections. In weaned piglets, challenged with E.coli, supplementation with beta-1,3/1,6-glucans reduced the duration and severity of diarrhoea and the susceptibility to colonisation with E. Coli . In a study with laying hens suffering from chronic enteritis, beta-1,3/1,6-glucan supplementation significantly reduced inflammatory cell infiltration and improved general health indicators in the hens.

SPECIFIC FOD-HY Allergen Management Plus can best be used for a young cat with IBD and struvite urolithiasis:

The diet is hypoallergenic (based on hydrolysed salmon protein and rice). For pets with IBD a hypoallergenic diet is often recommended, since it is expected that IBD can have a food allergic origin

The diet has high levels of omega-3 fatty acids from fish, which can dampen inflammatory reactions (in studies in humans and rats, high intake of n-3 reduced the severity of colitis)

The diet is suited for all ages, thus also for young growing cats

The diet is formulated to prevent struvite through the induction of a low urinary pH (< 6.4)

For diabetic cats with pancreatitis SPECIFIC FED-DM is recommended because it has a very moderate level of fat for support in case of pancreatitis

In case of mild to moderate constipation in cats, diets with a high level of insoluble fiber, such as cellulose, (e.g. SPECIFIC FRD/FRW Weight Reduction) can be beneficial. Insoluble fibers increase fecal bulk, which can improve peristalsis and normalize motility, on the condition that the cat is well hydrated and consumes sufficient water. 

However, in cats with more severe, chronic or recurrent constipation (obstipation) and megacolon it is not recommended to provide high levels of insoluble fibre. As these cats are often dehydrated with associated increased water absorption from the colon, high intake of insoluble fibre in these cats may result in an even larger amount of even more firm and drier fecal mass in the colon. Instead, it is therefore recommended to feed a highly digestible diet to reduce the amount of feces in the colon. A moderate amount of soluble fibre can help to increase the water content in the colon. Psyllium is a soluble gel-forming fiber which can soften the feces and help retain water in the colon.  Fermentable soluble fibers, such as beet pulp, inulin and FOS, can be metabolised into short-chain fatty acids (SCFAs), important nutrients for the colonocytes. Fermentation and production of SCFAs can promote colonic motility and increase fecal water as a result of  the osmotic effect of the metabolites. Within the SPECIFIC range, SPECIFIC FID and FIW Digestive Support are highly digestible diets with added soluble and fermentable fibres (psyllium, beet pulp, FOS, MOS, XOS), which can especially be recommended for cats with chronic constipation, obstipation and megacolon. As sufficient water intake is essential, especially the wet diet FIW is recommended, but water can also be added to the dry kibbles and intake of drinking water stimulated by providing multiple water bowls or water fountains.  

Depending on the response of the individual cat, additional use of a laxative as lactulose can be considered, with the dose titrated to reach the desired effect. 

 In general any change of diet can lead to some degree of temporary digestive disturbance. Of course this can be due to a nutritional inadequacy or a defect in the new diet but even the change itself may require some adaptation of digestive enzymes and intestinal microflora. A gradual switch mixing more and more of the new diet into the old one in the feeding bowl until the change is complete should be done over a period of 7-10 days. This is important for any change of diet and the pet owner should be properly informed about this. Exceptions to this procedure would be clearly acute cases where a therapeutic diet must be introduced as quickly as possible, e.g. a digestive or recovery diet. 

If digestive problems are seen/reported in conjunction with a diet change it should always be investigated first whether any other factors could be the cause. Have any other factors in the life of the pet changed recently? Has the pet had access to other sources of food or things to ingest? Did the pet’s feeding or eating routine change in any way?

For dogs with chronic diarrhoea associated with severe protein loosing enteropathy or lymphangiectasia SPECIFIC CID-LF/CIW-LF Digestive Support Low Fat is recommended. The unique combination of the use of hypoallergenic ingredients and the low dietary level of fat make the Digestive Support Low Fat diets perfectly suited for these clinical indications. The major part (about 66%) of dogs with chronic enteropathies are diet-responsive, meaning that they show improvement on a hypoallergenic diet. However, for several of these cases also a low-fat dietary fat level is required for management of clinical signs.

In addition to the hypoallergenic ingredients and the low fat content, SPECIFIC Digestive Support Low Fat diets also contain fermentable fibers, beta-glucans, relatively high levels of fish oil, AuraGuard and nucleotides to support a healthy gut microbiome, immune response and gut barrier function.  

For management of pancreatitis it is advised to avoid too much fat and protein in the diet to prevent stimulation of the pancreas.

The guidelines for diets for dogs with pancreatitis is a fat level of 10-15% on dry matter basis and a  protein level 15-30% dry matter. For severe cases of pancreatitis or cases with concurrent hyperlipidaemia or severe obesity an even lower dietary fat level (below 10% in dry matter) is recommended.

Within the SPECIFIC range the general recommendation for dogs with pancreatitis is CID-LF/CIW-LF Digestive Support Low fat (7% fat in DM) or CID/CIW Digestive Support, CDD-HY Food Allergen Management or COW-HY Allergen Management Plus (these diets have fat levels between 10 and 15% DM)

Depending on the condition and potential concurrent clinical conditions of an individual dog, another diet might be preferred. Please click on the link for recommended diets for dogs with pancreatitis and concurrent conditions.
 

Pancreatitis diet reccomendations - click here

For nutritional management of pancreatitis is it generally advised to prevent too much fat and protein in the diet to prevent stimulation of the pancreas. The guideline is to provide a diet with a moderate level of fat (10-15% on dry matter) and a protein level between 15-30% dry matter. For more severe cases or in case of concurrent hyperlipidaemia or obesity, an even lower fat content below 10% dry matter is recommended. For support of kidney failure it is essential to provide a diet with a restricted level of P and also protein is preferably reduced.Unfortunately the kidney diets are somewhat too high in fat to meet the guidelines for pancreatitis (CKD 17.5 and CKW 16.4% fat on DMB).

From the list of suitable SPECIFIC dog diets for pancreatitis (fat and protein in requested range), CGD Senior (13.4 g protein/MJ, P 0.35 g/MJ) and  CDD Food Allergen management (protein 10.1 g/MJ and P 0.34 g/MJ) ,can be used for dogs with pancreatitis and concurrent renal failure.  The phosphorus levels in these diets are still higher compared to the kidney diets. A phosphorus-binder could be added to these diets in order to keep plasma phosphorus levels within the desired range.

When further reduction of the dietary fat, phosphorus or protein level would be required for individual cases, extra rice could be added to CGD or CDD. A recipe for a balanced, complete diet can be provided on request, when needed.   

Exocrine pancreatic insufficiency is characterized by greatly reduced secretion of pancreatic digestive enzymes. Consequently, maldigested food remains in the gastrointestinal tract and this can lead to diarrhoea, flatulence and bacterial overgrowth. For the management of exocrine pancreas insufficiency highly digestible diets as SPECIFIC CID/W Digestive Support are recommended.  Also the hypoallergenic diets based on hydrolysed salmon protein and rice (SPECIFIC CDD-HY Food Allergen Management and COD-HY/COW-HY Allergen Management Plus are highly digestible and therefore recommended for dogs with exocrine pancreas insufficiency. Despite the fact that the diets are highly digestible, it is recommended that pancreatic enzyme preparations (such as for instance Primazym) are used in additional to these highly digestible diets.ons.

For dogs with pancreatitis it is recommended to give a diet with a moderate level of fat and protein in order not to stimulate the pancreas too much. Rule of thumb is a fat level from 10-15% on a dry matter basis and a protein level of 15-30% on dry matter basis.

For management of IBD and also for allergenic skin reactions, hypoallergenic diets are recommended and high levels of EPA and DHA from fish can help to support the body’s natural anti-inflammatory response.

SPECIFIC CID-LF / CIW-LF Digestive Support Low Fat meets all these criteria and is recommended for dogs with pancreatitis with concurrent IBD and allergic skin reactions.
The presence of fermentable fibers, beta-glucans, AuraGuard and nucleotides furthermore help to support a healthy gut microbiome, immune response and gut barrier function.

 Multi disorder cases like this cannot be easily managed nutritionally. The major consideration will be to balance the acuteness and risk of the different disorders with the possibility of nutrition to make a difference.

- In this case most attention should be given to the kidney disease and pancreatitis: Life expectancy of kidney patients has been shown to be considerably affected by a diet with low P and reduced protein. Low protein diet is also recommended for liver disease. Pancreatitis calls for moderate dietary fat and protein levels for minimal stimulation of the pancreas. (Rule of thumb for dogs: Fat level of 10-15% on dry matter basis and protein 15 -30% DMB.)

- Arthritis, though painful, is not life threatening, but closely connected into a vicious circle with the overweight. Both will improve if the dog loses weight and gets dietary GAGs and high levels of omega-3.

- Struvite problems in dogs are very often caused by urinary tract infections, so this should be investigated prior to any dietary considerations.

Unfortunately the kidney diets are somewhat too high in fat to meet the guidelines for pancreatitis (CKD 17.5 and CKW 16.4% fat on DMB).

In the list of suitable dog diets for pancreatitis (fat and protein in requested range), some diets could be considered (CGD 13.4 g protein/MJ, P=0.35 g/MJ), CDD protein 10.1 g/MJ and P 0.34 g/MJ), but in fact these P levels are still quite high compared to the kidney diets (0.16 g P/MJ).

DIETARY RECOMMENDATION:

Since there is no single ideal diet for this case, it is recommended  to adapt the kidney diets somewhat by mixing them with CGD (low fat, relatively low P and protein diet) or with cooked rice (providing primarily carbohydrates, thus reducing the % of protein and fat in the diet). A benefit of using CGD is that this is also a complete diet- so all nutrients are present in sufficiently high amounts. Benefit of using the rice is that you can get to some lower P levels, but also other nutrients are somewhat diluted (not expected to cause  problems caused by this), however by using a mix with CGD the level of omega-3 levels remains higher which is beneficial for kidney and joints.

Just evaluate which recipe looks best for this individual dog (dependent on breed size, price preference for CKD versus CKW – or palatability)

Mixing CKW with CGD-M:

Mix per 100 g CKW 20 grams CGD_M

This mixture will contain 11.2 g protein/MJ and 0,23 g P/MJ. Protein = 18.9% on DMB, Fat = 13.7% DMB. Feeding advice: give 61% of recommended feeding amount of CKW (feeding table) and add 20% of this amount as CGD

(example: 14 kg dog: CKW recommendation is 660 g/day (feeding table). Thus give 61% = 400 g CKW and mix this with 0.2*400=80 g CGD-M)

Mixing CKD with CGD:

Mix per 100 g CKD 75 grams CGD-M

This mixture will contain 10.3 g protein/MJ and 0,23 g P/MJ. Protein = 16.9% on DMB, Fat = 14.2% DMB. Feeding advice: give 60% of recommended feeding amount of CKD (feeding table) and add 75 % of this amount as CGD

Mixing CKW with cooked rice (weight of rice = weight after cooking)

Mix per 100 g CKW 30 gram cooked rice

This mixture will contain 8.7 g protein/MJ and 0.14 g P/MJ. Protein = 14.3% on DMB, Fat = 12.6% DMB. Feeding advice: give 78% of recommended feeding amount of CKW (feeding table) and add 30% of this amount as cooked rice

Mixing CKD with cooked rice (weight of rice = weight after cooking)

Mix per 100 g CKD 85 gram cooked rice

This mixture will contain 7.7 g protein/MJ and 0.14 g P/MJ. Protein = 12.7% on DMB, Fat = 14% DMB. Feeding advice: give 82% of recommended feeding amount of CKD (feeding table) and add 85% of this amount as cooked rice

For dogs with hyperlipidaemia / high cholesterol levels we recommend a diet with a reduced fat level as CID-LF/CIW-LF Digestive Support Low Fat, CRD-1/CRW-1 Weight Reduction, CRD-2 Weight Control or CED-DM Endocrine Support.

The fat level of CED-DM is not as low as in the other recommended diets, but still just low enough to comply with the maximum level of fat  indicated as essential nutritional characteristic for management of hyperlipidaemia (legislation for therapeutic diets, R 2020/354). In Digestive Support Low Fat and Endocrine Support diets a major part of the fat in the diet is derived from fish oil, which is also beneficial to reduce triglycerides and cholesterol.

A cat which was suffering from chronic diarrhoea and vomiting is now successfully maintained on SPECIFIC FID DIgestive Support. However the owner noticed that on the packaging it is indicated that the diet can only be fed for 12 weeks. Must the cat be switched to another diet?

The indication for the time of use, as indicated on the label of SPECIFIC FID DIgestive Support, is mandatory according the EU legislation for therapeutic diets (R 2020/354). The declaration of the recommended period of use indicates a range of time within which the nutritional purpose should normally be achieved. The purpose of this legal indication is that after this period a vet evaluates how the cat is doing on the diet and based on that will decide to continue the feeding of the diet or not.
On the packaging of FID to following indication of recommended time of use is given:
‘Initially up to 12 weeks and lifetime in case of chronic pancreatic insufficiency’

If this cat has been fed the SPECIFIC FID Digestive Support for this recommended period of use, and the cat is doing fine on the diet, the vet can recommend to continue to feed the diet. SPECIFIC FID Digestive Support is a diet, which meet the nutrient recommendations for all cats and can thus be fed for long-term.
Just as for all cats and dogs on any diet, it is recommended to monitor the pet's health and nutritional status on a regular basis, and adapt the diet if the nutritional assessment indicates that the diet should be adapted due to changes in the pet's condition or presence of concurrent clinical conditions.

For support of IBD a highly digestible diet is recommended. As an adverse food reaction may playa role in the development of IBD, a hypoallergenic diet will be preferred. Both IBD and osteoarthritis are inflammatory conditions which can benefit from the intake of high levels of imega-3 fatty acids EPA and DHA from fish oil, as these fatty acids can help to support the body’s natural anti-inflammatory response. From all nutraceuticals which are used for support of osteoarthritis, the efficacy of omega-3 fatty acids is best proven in controlled clinical trials.

SPECIFIC FOD-HY / FOW-HY Allergen Management Plus diets are hypoallergenic, highly digestible and contain high levels of EPA and DHA of fish oil and are therefore recommended for nutritional management of cats with IBD and concurrent osteoarthritis.

Nucleotides are organic molecules which form structural building blocks of DNA and RNA. They consist of a base (adenine, thymine guanine or cytosine in DNA and uracil in RNA), bound to a sugar and a phosphoric acid molecule.

Nucleotides have an important role in metabolism on cell level and can provide energy.

As building block of DNA and RNA, there is a high need on nucleotides in fast dividing cells (where new DNA and RNA is produced), such as in the intestinal mucosa (where cells are renewed within a few days) and immune cells. Nucleotides can be derived from de novo synthesis, but can also be derived from re-use from nucleotides from dead cells or derived from the food. Under normal conditions there is no need to provide extra nucleotides through the diet (de novo synthesis and re-use of nucleotides will be sufficient), but in periods of increased need (during stress, disease, vaccination, growth) there can be a higher demand for nucleotides and supplementation of nucleotides has shown to be beneficial.
It has for instance been shown that supplementation of nucleotides is associated with an increase in villi height and crypt depth in the intestinal mucosa, which is associated with an increase in absorptive surface, better absorption, improved growth and improved feed conversion rate. Nucleotide supplementation also supports the immune response, for instance by increasing the production of IgE after vaccination.

SPECIFIC CDD-HY and COD-HY contain the same hypoallergenic ingredients (based on hydrolysed salmon and rice). Both diets contain pork fat and fish oil, but the levels of the fat sources are different: CDD-HY contains more pork fat and COD-HY contains more fish oil. As eosinophilic enteritis is an inflammatory condition, SPECIFIC COD-HY will be preferred; the high levels of EPA and DHA from fish oil in COD-HY can help to support the body’s anti-inflammatory response.

For a cat with diabetes and struvite we would recommend FEW-DM. The urine pH of cats fed  FEW-DM  is below6.4 and by giving a wet diet the chance of crystal formation is always much lower than on a dry diet (on FED-DM the urine pH is just a little higher, 6.4-6.6, and therefore less suitable for support of cats with a history of struvite urolithiasis)

Calcium phosphate stones are often related to abnormalities in the calcium metabolism (unless special supplements rich in calcium or vitamin D are given). In these cases it is recommended to perform further research for underlying problems  and to feed a kidney diet (preferably wet).

The content of GAGs (150 mg/MJ) in FJD/FJW supports maintenance of healthy cartilage and increased synthesis of proteoglycans. This may theoretically also be a benefit for protection of the bladder wall in case of idiopathic cystitis in cats  (IC). In cats with IC, the protective GAG-lining of the bladder is thinner than on normal cats. Although anecdotally used with beneficial effects, there are yet no double-blinded placebo-controlled studies proving the efficacy of GAGs in cats with IC. In a double blinded study with cats with IC individual cases showed a clear effect and relapsed after stopping the GAG supplementation, but the effect was not significant vs. the control group. This study by GunnMoore confirmed (as already shown by Markwell et al) that a simple switch to a wet diet would reduce relapse of IC episodes in cats.

The SPECIFIC diet recommendation for managing cases of joint problems and IC would be FJW.
 

First of all, it is important to note that the presence of struvite in cat urine is not necessarily alarming. Also in healthy cats without urinary tract problems, struvite crystals can be present in the urine. It will only become alarming when there are many struvite crystals and when they form aggregates.

Presence of crystals cannot be considered as a disease. Struvite crystals are present in urine of both stone formers and non-stone formers (Carbone M.G. Phosphocrystalluria and urethral obstruction in the cat. J. Am. Vet. Med. Assoc 1965: 147: 1195-1200). Apparently, the development of struvite urolithiasis not only depends on the presence of struvite crystals, but there are several interrelated complex physiologic and pathogenic factors involved (such as presence and/or absence of inhibitors and promotors of crystal precipitation and aggregation). As also stated by Allen and Kruger: ‘Detection of crystalluria does not mean a cat will subsequently develop urolithiasis. Crystalluria that occurs in cats with normal anatomy and physiology of the urinary tract is usually of no clinical significance (Allen T.A. & Kruger J.M. Feline Lower urinary Tract Disease in: Small Animal Clinical Nutrition (Eds Hand, Thatcher, Remillard and Roudebush), 2000, Mark Morris Institute).

The presence of struvite crystals could the results of a urinary tract infection. It is therefore recommended to check for this.

The presence of urate crystals in cats is rather rare, so it is therefore recommended to direct the nutritional management on the reduction of urate urolithiasis. Urate crystals can only precipitate when the urine is acid and they are often formed as a result of liver disorders. It is recommended to check what diet the cat is currently fed and if it has any liver problems.

For the reduction of recurrence of urate urolithiasis SPECIFIC FKW Kidney Support is recommended. Since this is a wet diet, it will induce a more diluted urine and will thereby reduce the risk on any kind of urolithiasis.

Ammonium urate urolithiasis is promoted by high concentrations of ammonium and urate in the urine and a low urine pH. In healthy animals, purines (from DNA) are converted into allantoin. In animals with impaired liver function or liver shunt, purines are not converted to allantoin, but to urate. In cats, however, the cause is usually unknown. The production of acidic and concentrated urine, combined with a diet rich in purine (for example, liver) is described as cause.

The guidelines for a diet for solution and reduction of recurrence of ammonium urate are the following:

The use of low-purine raw materials, such as eggs, milk products and rice.
A low protein content in the diet to reduce the supply of purines and a decrease in the ammonium content in the urine.
The induction of a urinary pH in the range of 6.5-7.5 to promote urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of urate formation, the general advice is to prevent crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water absorption can be achieved by giving the cat a wet food (canflex / pouch) or by soaking dry kibbles in water. Giving a wet food will increase the water intake the most, especially if some extra water is mixed with the wet food.

The diets we recommend for ammonium urate urolithiasis in cats: SPECIFIC FKD / FKW / FKW-P

 SPECIFIC Kidney Support (FKD / FKW / FKW-P) can be prescribed to dissolve and reduce recurrence of ammonium urate stones in cats. These diets are not exclusively made from low-purine raw materials, but due to the reduced protein content and the induction of a higher urinary pH, they are suitable for the prevention of urate stones.

It is recommended to monitor regularly for urine pH, specific gravity, presence of crystals, urinary tract infection and any new stones. The guideline is to keep the specific gravity of the urine below 1.030 and the urine pH between 6.5 and 7.5. If the cat's urine pH is too low, potassium citrate can help make the urine more alkaline.  Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired).

Since urate stones are often caused by hepatic impairment, it is recommended to monitor the liver function of the cat. In addition to diet, allopurinol can be given in animals with recurrent urate stones, but this is not common in cats.

Calcium oxalate urolithiasis is promoted by high concentrations of calcium and oxalate in the urine. Existing calcium oxalate stones cannot be dissolved and must be surgically removed. A diet is recommended to prevent recurrence.

The guidelines for a diet to reduce calcium oxalate recurrence in cats are the following:

• A low protein content in the diet, because the amino acid glycine is a precursor of oxalate.
• An induction of a urine pH between approx. 6.5 and 7.5 because an excessively acidic urine could cause calciuria.
• Low sodium in the diet to prevent calciuria.

In addition to the above-mentioned specific guidelines for the reduction of calcium oxalate formation, the general advice also applies to counteract crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water intake can be achieved by giving the cat a wet food (alucup / pouch) or by soaking dry kibbles in water.

It is further advised to monitor regularly for urine pH, presence of crystals, urinary tract infection and any new stones. If the urine pH is below 6.5, potassium citrate can be given to slightly increase the urine pH. The advice is to keep the specific gravity of the urine below 1.030.

With recurrent calcium oxalate stones, it is advisable to investigate whether there are underlying causes for a disturbance in the calcium balance that can possibly be treated (see appendix).

 The diets we recommend for calcium oxalate urolithiasis in cats: SPECIFIC® FKD / FKW / FKW-P

 SPECIFIC® Kidney Support (FKD / FKW / FKW-P) is for the reduction of recurrence of calcium oxalate stones in cats. These kidney diets are very tasty and due to the reduced protein and sodium content and the induction of an alkaline urine pH suitable for the reduction of recurrence of calcium oxalate stones.

If the cat's urine pH is too low, potassium citrate can help make the urine alkaline and keep calcium and oxalate in solution. The guideline is a urine pH between 6.5 and 7.5. Starting dose 2 times 50-75 mg / kg.

The dose is a starting dose and good monitoring / adjustment is desired (pH guided, 2 weekly monitoring

APPENDIX

Conditions related to calcium-containing uroliths

In case of recurrent calcium-containing uroliths, there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these. 

• Primary hyperparathyroidism
  As a result of the increased PTH-level, the Ca-absorption from the bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 Vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.

Animals with primary hyperparathyroidism can be treated with parathyroidectomy.

• Other conditions related to hypercalcemia:
  • Hypervitaminosis D
  • Neoplasia
  • Hyperthyroïdism
  • Cushing-syndrome
     
• Distal Renal Tubular Acidosis
  These animals have problems keeping the H+-gradient. The associated hypercalciuria, hyperfosfaturia en hypocitraturia can be treated by alkalization and supplementation with K-citrate.

• Normocalcemic hypercalciuria
  ​Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
    The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

Advice for dogs and cats with recurring calcium-containing uroliths

1. Try to detect the cause for the recurrence of the stones (associated conditions?):

• Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, Vit D, Mg, urate, blood gasses
• Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
• Examine urinary tract (X-ray, ultra sound)
   

Dietary advice:

• Increase the urine volume by feeding a wet diet (or add water to a dry diet)
• Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and a less concentrated urine.
• For the prevention of hypercalciuria and hyperphosphaturia, a diet with a low level of Ca, Na, P and vit D should be given
• (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
• Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine

Additional advice:

• Avoid drugs that can increase the urinary calcium excretion
• (e.g. glucocorticosteroids, furosemide, acetazolamide)
• Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3- portions per day.

Try to detect the cause for the recurrence of the stones (associated conditions?):

• Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, vitamin D, Mg, urate, blood gasses
• Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
• Examine urinary tract (X-ray, ultra sound)

Dietary advice:

• Increase the urine volume by feeding a wet diet (or add water to a dry diet). It is recommended to keep the specific gravity below 1.030.
• Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and less concentrated urine.
• For the reduction of hypercalciuria and hyperfosfaturia, a diet with a low level of Ca, Na, P and vitamin D should be given
• (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
• Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine
• For the prevention of calcium phosphate urolithiasis in cats we recommend SPECIFIC FKD/FKW/FKW-P Kidney Support:
• These diets have a reduced level of protein level, Ca, Na, P and the vitamin D level is not extremely high. By feeding FKW or FKW-P (to which even some extra water can be added) water intake most increased and urine thereby most diluted.      

Additional advice:

• Avoid drugs that can increase the urinary calcium excretion (e.g. glucocorticosteroids, furosemide, acetazolamide)
• Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3 portions per day

Calcium phosphate uroliths (such as hydroxyapatite, brushite, whitlockite) are uncommon in cats and are often associated with underlying conditions such as hypercalcemia, hyperparathyroidism and hypervitaminosis D.

Important determinants of the solubility of calcium phosphate:

1. Urine pH. Most calcium phosphate (CaP) stones typically form in an alkaline medium and are more soluble in an acidic medium. This does not apply to brushite: the solubility of brushite decreases when the urine pH drops.
2. The concentration of calcium (Ca) in the urine: this may be increased due to increased Ca absorption from the bone, increased calcium absorption from the gastrointestinal tract or increased calcium leakage in the kidney
3. The concentration of phosphorus (P) in the urine. Increased P absorption leads to an increased P concentration in the urine
4. Inhibitors of the formation of calcium phosphate crystals: e.g. components that bind to components of the crystal (e.g. citrate, which binds calcium and keeps it in solution) or components that disturb the structure of the crystal (e.g. incorporation of magnesium in CaP crystal)
5. Presence of components that promote the precipitation of CaP crystals (e.g. the presence of calcium oxalate crystals promotes the precipitation of CaP)

In case of pure calcium phosphate urolithiasis there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these: 

Primary hyperparathyroidism

• As a result of the increased PTH-level, Ca-absorption from bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 Vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.
• Animals with primary hyperparathyroidism can be treated with parathyroidectomy.

Other conditions related to hypercalcemia:

• Hypervitaminosis D
• Neoplasia
• Hyperthyroïdism
• Cushing-syndrome

Distal Renal Tubular Acidosis

• These animals have problems to keep the H+-gradient. The associated hypercalciuria, hyperfosfaturia en hypocitraturia can be treated by alkalization and supplementation with potassium-citrate.

Normocalcemic hypercalciuria

• Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
• The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

For combined stones composed of struvite and urate, it is recommended to direct the management on  the reduction of recurrence of urate formation. Ammonium urate urolithiasis is promoted by high concentrations of ammonium and urate in the urine and a low urine pH. In healthy animals, purines (from DNA) are converted into allantoin. In animals with impaired liver function or liver shunt, purines are not converted to allantoin, but to urate. In cats, however, the cause is usually unknown. The production of acidic and concentrated urine, combined with a diet rich in purine (for example, liver) is described as cause.

The guidelines for a diet for solution and reduction of ammonium urate are the following:

• The use of low-purine raw materials, such as eggs, milk products and rice.
• A low protein content in the diet to reduce the supply of purines and a decrease in the ammonium content in the urine.
• The induction of a urinary pH in the range of 6.5-7.5 to promote urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of urate formation, the general advice is to prevent crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. To also prevent struvite formation, it is recommended to keep the specific gravity of the urine below 1.030. Increased water intake can be achieved by giving the cat a wet food (canflex or pouch) or by soaking dry kibbles in water. Giving a wet food will increase the water intake the most, especially if some extra water is mixed with the wet food.

The struvite formation can result from a bacterial urinary tract infection. It is therefore advised to check for the presence of a urinary tract infection and, if present, to treat it with antibiotics.

It is further advised to regularly monitor the cat for urine pH, presence of crystals and any new stones. If the urine pH is below 6.5, potassium citrate can be given to slightly increase the urine pH. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired).

The diets we recommend for ammonium urate urolithiasis in cats: SPECIFIC FKD / FKW / FKW-P

SPECIFIC Kidney Support (FKD / FKW / FKW-P) can be prescribed to dissolve and reduce recurrence of ammonium urate stones in cats. These diets are not exclusively made from low-purine raw materials, but due to the reduced protein content and the induction of a higher urinary pH, they are suitable for the reduction of recurrence of urate stones.

Since urate stones are often caused by hepatic impairment, it is recommended to monitor the liver function of the cat. In addition to diet, allopurinol can be given in animals with recurrent urate stones, but this is not common in cats.

A stone with a combination of calcium oxalate and struvite usually forms as a calcium oxalate stone. This stone causes irritation of the bladder, which makes it more sensitive to an infection. During an infection with urease-positive bacteria, urea in the urine will be converted into ammonium. During this conversion, the urine pH will also rise. The increase in the ammonium concentration and the urinary pH will then give rise to the precipitation of struvite. This will results in a combined stone with a core of calcium oxalate, covered by a struvite shell.

Combined stones with calcium oxalate and struvite cannot be dissolved and must be surgically removed. The prevention of recurrence is directed against the type of crystal that is in the core of the stone (initial problem = calcium oxalate). In addition, it is important that the infection is treated with suitable antibiotics.

The guidelines for a diet to reduce calcium oxalate recurrence in cats are the following:

• A low protein content in the diet, because the amino acid glycine is a precursor of oxalate.
• An induction of a urine pH between approx. 6.5 and 7.5 because an excessively acidic urine could cause calciuria.
• Low sodium in the diet to prevent calciuria.

In addition to the above-mentioned guidelines for the prevention of calcium oxalate formation, the general advice also applies to counteract crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water intake can be achieved by giving the cat a wet food (canflex or pouch) or by soaking dry kibbles in water.

It is further advised to monitor regularly for urine pH, presence of crystals, urinary tract infection and any new stones. If the urine pH is below 6.5, potassium citrate can be given to slightly increase the urine pH and keep calcium in solution. The advice is to keep the specific gravity of the urine below 1.030. With recurrent calcium oxalate stones, it is advisable to investigate whether there are underlying causes for a disturbance in the calcium metabolism that can possibly be treated (see appendix).

The diets we recommend for combined struvite and calcium oxalate urolithiasis in cats: SPECIFIC® FKD / FKW / FKW-P

SPECIFIC Kidney Support (FKD / FKW / FKW-P) is for the reduction of recurrence of calcium oxalate stones in cats. These kidney diets are very tasty and due to the reduced protein and sodium content and the induction of an alkaline urine pH suitable for the reduction of calcium oxalate stones.

If the cat's urine pH is too low, potassium citrate can help make the urine alkaline and keep calcium and oxalate in solution. The guideline is a urine pH between 6.5 and 7.5. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjusted is advised).

APPENDIX

Conditions related to calcium-containing uroliths

In case of recurrent calcium-containing uroliths, there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these. 

• Primary hyperparathyroidism
  As a result of the increased PTH-level, the Ca-absorption from the bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 Vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.
  Animals with primary hyperparathyroidism can be treated with parathyroidectomy.
   
• Other conditions related to hypercalcemia:
  • Hypervitaminosis D
  • Neoplasia
  • Hyperthyroïdism
  • Cushing-syndrome
     
• Distal Renal Tubular Acidosis
  These animals have problems keeping the H+-gradient. The associated hypercalciuria, hyperfosfaturia en hypocitraturia can be treated by alkalization and supplementation with K-citrate.
   
• Normocalcemic hypercalciuria
  ​​Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
    The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

Advice for dogs and cats with recurring calcium-containing uroliths

• Try to detect the cause for the recurrence of the stones (associated conditions?):
  • Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, Vit D, Mg, urate, blood gasses
  • Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
  • Examine urinary tract (X-ray, ultra sound)
     
• Dietary advice:
  • Increase the urine volume by feeding a wet diet (or add water to a dry diet)
  • Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and a less concentrated urine.
  • For the prevention of hypercalciuria and hyperphosphaturia, a diet with a low level of Ca, Na, P and vit D should be given
  • (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
  • Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine

Additional advice:

• Avoid drugs that can increase the urinary calcium excretion (e.g. glucocorticosteroids, furosemide, acetazolamide)
• Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3- portions per day.

A stone with a combination of struvite and carbonate apatite usually forms as a result of a urinary tract infection with urease-positive bacteria, when urea in the urine is converted into ammonium and the urine pH rises. This will then lead to the precipitation of struvite and, in case of increased urinary calcium excretion, also of carbonate apatite.

Important for the reduction of recurrence of combined struvite carbonate apatite stones is the treatment and prevention of urinary tract infections. With repeated urinary tract infections, it is important to investigate whether there are structural or functional causes for an increased risk of urinary tract infections, which can be corrected. In relation to the formation of carbonate apatite, it is recommended to check whether there is an increased serum calcium level or increased calcium excretion.

The guidelines for a diet for solution / reduction of struvite and carbonate apatite in cats are the following:

• A decrease in urine pH within the range of 6.0 - 6.5 to dissolve struvite and carbonate apatite.
• A reduction in the magnesium and phosphorus content in the diet in order to reduce the urine concentration of these components.
• Moderate dietary sodium to avoid increasing calcium excretion.

In addition to the above-mentioned specific guidelines for the prevention of struvite formation, there is also the general advice to prevent crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water absorption can be achieved by feeding the cat a wet food (canflex or pouches) or by soaking dry kibbles in water.

The diet we recommend for cats with combined struvite / carbonate apatite urolithiasis is: SPECIFIC® FCD, FCD-Light, FCW, FCW-P

SPECIFIC® FCD, FCW, FCW-P and FCD-Light Crystal Management are advised to dissolve remnants of the stones and to prevent recurrence. These diets are very tasty and meet the above guidelines.

It is further advised to monitor regularly for urine pH, presence of crystals, urinary tract infection and any new stones. The advice is to keep the specific gravity of the urine below 1.030.

Cystine urolithiasis is promoted by a high urinary cystine concentration and a low urinary pH. Cystine is made in the body from the sulfur-containing amino acids cysteine and methionine and is reabsorbed from the pre-urine in the renal tubuli. Due to a hereditary defect, some animals reabsorb less cystine from the pre-urine and have higher urinary cystine concentrations. Existing cystine stones can be resolved through an adjusted diet and use of medication (2-mercatopropionyl glycine, MPG). A diet is recommended to prevent recurrence.

The guidelines for a diet for the reduction of recurrence of cystine in the cat are the following:

• A low protein content in the diet, because it contains less cysteine and methionine. Therefore less cystine will be excreted in the urine and less cystine stoned can be formed.
• An induction of a urinary pH> 7.5 to increase the solubility of cystine.
• A moderate sodium content to limit cystine secretion.

In addition to the above-mentioned specific guidelines for the reduction of cystine crystal formation, the general advice is also to prevent crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water absorption can be achieved by giving the cat a wet food (canflex or pouch) or by soaking dry kibbles in water.

The diets we recommend for cystine urolithiasis in cats: SPECIFIC® FKD / FKW / FKW-P

SPECIFIC Kidney Support (FKD / FKW / FKW-P) is for the dissolution and reduction of recurrence of cystine stones in cats. These kidney diets are very tasty and due to the reduced protein and sodium content and the induction of an alkaline urine pH suitable for the prevention of cystine stones.

Optionally, 2-mercaptopropionyl glycine (MPG) can be given as a support drug. In the dissolving phase, the dosage twice daily is 15-20 mg / kg, and preventively 15 mg / kg twice daily.

Regular monitoring is recommended, aiming for a SG of the urine <1.030 and a urine pH> 7.5. If necessary, potassium citrate can be given to raise the urine pH> 7.5.

Struvite urolithiasis (precipitation of magnesium ammonium phosphate in the lower urinary tract) is promoted by high concentrations of magnesium, ammonium and phosphate in the urine and the presence of an alkaline urine pH.

The guidelines for a diet for solution / reduction of recurrence of struvite in cats are the following:

• A decrease in urinary pH within the range of 6.0 - 6.5 to dissolve struvite.
• A reduction in the magnesium and phosphorus content in the diet in order to reduce the urine concentration of these components of struvite.

In addition to the above-mentioned specific guidelines for the prevention of struvite formation, there is also the general advice to prevent crystal formation by giving the cat plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water absorption can be achieved by giving the cat a wet food (canflex or pouch) or by soaking dry kibbles in water.

The diets we recommend for cats with struvite urolithiasis: SPECIFIC FCD, FCD-Light, FCW, FCW-P and FSW

SPECIFIC FSW Struvite Dissolution and SPECIFIC FCD, FCD-Light, FCW and FCW-P Crystal Management are recommended to dissolve struvite stones and reduce recurrence. These diets are very tasty and meet the above guidelines.

It is recommended to monitor regularly for urine pH, specific gravity, presence of crystals, urinary tract infection and any new stones. The guideline is to keep the specific gravity of the urine below 1.030 and the urine pH between 6.0 and 6.5.

Struvite urolithiasis in cats, in contrast to dogs, is usually not associated with a urinary tract infection, and it is recommended to give cats SPECIFIC Crystal Management long-term for the prevention of recurrence. In the less common case of struvite urolithiasis associated with a urinary tract infection in a cat, in addition to providing SPECIFIC Crystal Management or Struvite Dissolution, it is recommended that the infection be treated with appropriate antibiotics.

Xanthine stones are relatively rare. Xanthine is a product of the breakdown of purines (which are found in DNA). In healthy cats, purines are converted into allantoin, a substance that is highly water-soluble and is excreted in the urine without any problems. Due to a hereditary abnormality a deficiency in the enzyme xanthine oxidase can occur. As a result, purines will be concerted to xanthine. Xanthine is not very soluble in water and xanthine stones will be formed if urine concentrations of xanthine are too high and especially at a low urine pH.

In addition, xanthine stones in cats can also result from the treatment of urate stones with allopurinol. Both urate and xanthine are breakdown products of purines. Allopurinol inhibits the activity of the enzyme xanthine oxidase. If urate stones are treated with allopurinol, but at the same time many purines remain available through the diet, the cat will not form urate stones, but xanthine stones. It is therefore important to prescribe a special low-purine diet when using allopurinol.

The guidelines for a diet for reduction of xanthine (and urate) are the following:

• The use of low-purine raw materials, such as eggs, milk products and rice.
• A low protein content in the diet to reduce the supply of purines.
• The induction of a urinary pH in the range of 6.5-7.5 to promote xanthine and urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of xanthine and urate formation, the general advice also applies to giving the cat plenty of water through the diet, in order to prevent crystal formation. This will increase the urine volume and make urine less concentrated. It is recommended to keep the specific gravity below 1.030. Increased water intake can be achieved by feeding the cat a wet food (canflex or pouch) or soaking dry kibbles in water.

Diets we recommend for xanthine urolithiasis in cats: SPECIFIC FKD / FKW / FKW-P

SPECIFIC Kidney Support (FKD / FKW / FKW-P) can be prescribed to reduce recurrence of xanthine stones in cats. These diets are not exclusively made from low-purine raw materials, but due to the reduced protein content and the induction of a higher urinary pH, they are suitable for the prevention of xanthine stones.

It is recommended to monitor regularly for urine pH, specific gravity, presence of crystals, urinary tract infection and any new stones. The guideline is to keep the specific gravity of the urine below 1.030 and the urine pH between 6.5 and 7.5. If the cat's urine pH is too low, potassium citrate can help make the urine more alkaline.  Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired).

For kittens with struvite urolithiasis, which are 6 months or older we recommend SPECIFIC FCD, FCW or FCD-L Crystal Management (Light). Kittens older than 6 months of age have already passed the first growth phase and will be able to cope with the reduced mineral level in FCD (-L) and FCW.

(FSW is not recommended for kittens, since these diets are more restricted in minerals. From practice we know that also FCD, FCW and FCD-L will be efficient in dissolving struvite stones and crystals and will reduce formation of new ones).

Especially in case of very young kittens it is recommended to check for the presence of a urinary tract infection. At very young age, the primary problem of struvite urolithiasis is often a urinary tract infection. For these cases it will probably be enough to give antibiotics in combination with an anti-struvite diet. If the infection is well controlled, the problems with struvite crystals will probably also disappear. A short period (4-6 weeks) of anti-struvite diets will then probably be long enough. During such a short period an anti-struvite diet as FCD, FCW or FCD-L will not harm the kitten.

However if the kitten is very young and/or if the diet needs to be fed for a longer period, then it is recommended to feed an acidifying diet which also meets the mineral requirement of kittens. Within the SPECIFIC range there are several diets which meet the nutrient requirement of kittens (All Ages / Neutered Young) and are also acidifying (pH< 6.4). Urine trials have also shown that the following diets induce a urine with an RSS value for struvite < 1:

• SPECIFIC FND Neutered Young
• SPECIFIC FOD-HY Allergy Management Plus
• SPECIFIC FID/W Digestive Support

For the treatment of urine stones and crystals correct diagnosis and strict nutritional management are important. SPECIFIC  FSW Struvite Dissolution  and SPECIFIC FCD, FCD-L, FCW and FCW-P Crystal Management can all be used for dissolution of struvite urolithiasis.  Due to its extra low mineral content, W it is recommended to use FSW for a maximum of 2-3 months.  (Note: The EU legislation for dietetic diets for dissolution of maximum uroliths prescribes that a  maximum period of use of time of 5-12 weeks needs to be added on the label of all diets for dissolution of struvite If cats with struvite are exclusively fed with FSD, FCD, FCD-L, FCW or FCW-P,   struvite stones should be dissolved after this 2-3 month period. .

Successful dissolution of the struvite uroliths should be confirmed by urinalysis/microscopy  or imaging and then FCD/FCW/FCW-P or FCD Light can be used to reduce recurrence of struvites..

NB: It must be noted that FCD, FCW, FCW-P and FCD-L (or a combination of these diets) are fed exclusively and no other food (mineral sources) are fed!

In case of recurrence of struvite:

1. Rule out the presence of a urinary tract infection. A urinary infection  will increase the urinary pH in favour of struvite precipitation. (In dogs struvite problems are very often secondary to urinary tract infections.) Appropriate antibiotics should be given until bacterial infection is under control, and importantly also until stones have completely dissolved. Stones may contain viable bacteria and continuously release these as the stone gradually dissolves.
2. For pets with relapsing urolithiasis problems it is  recommended to use a wet diet (FSW, FCW, etc.). This will provide water through the diet itself leading to a more urine, more diluted urine, higher frequency of urination thus reducing the risk of crystal precipitation.
3. Reconsider diagnosis according to symptoms and urinalysis/microscopy findings:
   1. Even in healthy cats some struvite crystals can be present.
   2. Are struvite stones or very large amounts of struvite crystal present?Are crystals and/or other material forming aggregates or plugs?
   3. Urinary tract symptoms in cats may be caused by idiopathic cystitis. ( Consider a wet diet (FCW, FXW), since it has been shown that a wet diet reduced the number of relapses in cats with idiopathic cystitis).
   4. Are observed uroliths indeed composed of struvite?

The indication for the time of use, as indicated on the label of SPECIFIC Special Care (dietetic) diets, is mandatory according to the EU legislation for therapeutic diets (R 2020/354). The legal declaration of the recommended period of use indicates a range of time within which the nutritional purpose should normally be achieved. The purpose of this legal indication is that after this period a vet evaluates how the dog/cat is doing on the diet and based on that will decide to continue the feeding of the diet or not.

On the label of SPECIFIC Special Care products, the recommended time of use according each PARNUT is given.

If the cat/dog has been fed the SPECIFIC Special Care diet for this recommended period of use, and the cat/dog is doing fine on the diet, the vet can recommend to continue to feed the diet. SPECIFIC Special Care diets are complete diets, which meet the nutrient recommendations for adult cats/dogs and can thus be fed for long-term.

Just as for all cats and dogs on any diet, it is recommended to monitor the pet's health and nutritional status on a regular basis, and adapt the diet if the nutritional assessment indicates that the diet should be adapted due to changes in the pet's condition or presence of concurrent clinical conditions.

SPECIFIC FOD-HY Allergy Management Plus can best be used for a young cat with IBD and struvite urolithiasis:

• The diet is hypoallergenic (based on hydrolysed salmon protein and rice). For pets with IBD a hypoallergenic diet is often recommended, since it is expected that IBD can have a food allergic origin
• The diet has high levels of omega-3 fatty acids from fish, which can dampen inflammatory reactions (in studies in humans and rats, high intake of n-3 reduced the severity of colitis)
• The diet is suited for all ages, thus also for young growing cats
• The diet is formulated to prevent struvite through the induction of a low urinary pH (< 6.4)

Without complicating factors it is hardly possible that the urine pH of a cat on FCD is 8. In several batches of FCD the urine pH has been tested in urine trials. The urine  pH of different batches of FCD was very consistent and < 6.4. Occasionally a small fresh urine sample can be found with a pH above 6.4 during the postprandial alkaline tide ( a few hours after a large meal), but this is then immediately followed by urine with a pH <6.

So, one complicating factor could be that there is a urinary tract infection. If there is a bacterial infection, then bacteria will break down urea which is present in urine and will convert this into ammonium and OH- ions. As a result of this pH will increase, and the urine ammonium concentration will increase. Both of these changes will increase the risk on struvite precipitation.
Another complicating or disturbing factor can be that the urine was not fresh. If urine is not fresh and stored at room temperature for longer time, then also bacteria may start to grow, leading to an increase in urine pH.

It will also be useful to check if the cat did not had access to other food.

It has indeed been described in literature that there can be recurrence of calcium oxalate urolithiasis despite being switched to an ‘anti-calcium oxalate diet’ (but diet can help to prolong the time to relapse). This can especially be found in certain breeds with an increased risk on calcium oxalate urolithiasis (Miniature Schnautzers. Lhasa Apsos, Yorkshire Terriërs, Bichon Frises, Shih Tzus and Miniature Poodles).

Besides the feeding of a special diet which reduces the risk on calcium oxalate recurrence (such as SPECIFIC CKD/CKW Heart & Kidney Support), it is recommended to reduce the risk on further recurrence by giving more water:  try to dilute the urine further (especially when the dog has concentrated urine). It might be helpful to add some wet diet, mixed with water and mixed with the dry diet if feeding a wet diet (extra mixed with water) would be too expensive.

It is recommended to follow up if urine remains diluted.

Another thing which is important to consider is to check if there are any calcium oxalate stones left in the urinary tract (if they are relatively small they might be able to flush them out through voiding urohydropropulsion). It has been shown that after surgery often small ca-ox stones remain present in the urinary tract. Therefore check urinary tract by X-ray immediately after surgery. Presence of remaining calcium oxalate crystals or stones will act as a nidus and will facilitate the precipitation of new crystals a lot!

Aim for a urine pH of 7-7.5. If the pH of the urine in this dogs is not always around 7 (becoming more acid)  then extra potassium citrate may be given to increase the pH and the solubility of calcium salts

Furthermore it is known that dogs with calcium oxalate urolithiasis may have underlying conditions which increase the risk on relapse. It is therefore recommended to check for the presence of underlying causes related to recurrent calcium-containing stones and try to manage them if possible.

Follow up the dog closely and check for presence of ca-ox stones several times per year. If the stones are still small they can be flushed out (prevent that they grow too big as they cannot be dissolved and would need to be removed by surgery).

For dogs with brushite it is recommended to give SPECIFIC CKD/CKW Heart & Kidney Support. For smaller dogs use of the wet diet may be beneficial to further increase the water intake and thereby reduce the risk of crystal formation (also recommended to add some extra water to the wet, but also dry diet). Furthermore it is recommended to check for underlying causes related to the calcium metabolism and to treat them if possible to prevent recurrence of the brushite stones.

No, CED has not been specially formulated to have a low RSS for struvite stones/crystals.

Note: Struvite urolithiasis in dogs is more often secondary to a urinary tract infection than in cats. This also makes the role of the diet somewhat less important - the most important treatment for these dogs is appropriate antibiotics! CED does however contain e.g. beta-glucans to improve the immune response in dogs (and thus a better support also to resist urinary tract infections).

This dog has a urinary tract infection (UTI), struvite crystals as well as food allergies 

Since this is a dog with a UTI, treatment with antibiotics is the most important treatment; it is only temporarily that a struvite diet should to be used to dissolve existing struvite crystals. When the UTI is controlled with antibiotics and crystals have dissolved, then generally a dog with infection-induced struvite urolithiasis can be returned on a regular diet (for this dog this would be its hypoallergenic diet).

For the short time to give a hypoallergenic anti-struvite diet, it could be considered to give SPECIFIC FDD-HY or FOD-HY as these are acidifying and hypoallergenic diets. The diets are formulated for cats but are complete diets for dogs as well.

Urate urolithiasis in pups may be related to the presence of portosystemic shunts – it is therefore recommended to check for this.

In normal healthy dogs, purines (derived from endogeneous and dietary DNA) are broken down in the liver to allantoin, which dissolves well in water and will be excreted through the urine. In some breeds (e.g. Dalmation dogs) with a deviation in the purine metabolism or in dogs with portovascular anomalies, where the liver is surpassed, purines are not broken down to allantoin, but to urate which is not very soluble, especially not in an acid environment.

Our standard recommendation for nutritional management of urate urolithiasis is SPECIFIC CDD Food Allergy Management, because this diet is based on egg and rice (ingredients very low in purines), reduced in protein and inducing a more alkaline urine pH. However, the amount of protein in the diet is slightly too low for pups; also the calcium and phosphorus level is somewhat low for growing pups. It is therefore recommended to mix CDD with cottage cheese (also low purine ingredient) and a mineral supplement to formulate a diet which is low in purines, but meets the nutrient requirements of pups.

At the age of 4 months, a Jack Russel pup will be about 3-3.5 kg. With an expected adult body weight of 5-6 kg it is in the 2nd growth phase (meaning that it needs about 1.5 times the amount of feed recommended for an active adult dogs of the same weight). At the end of the growth, the amount can be reduced and also the extra cottage cheese and mineral mix can be skipped.

• At body weight of 3 kg: feed 100 g CDD + 40 gram cottage cheese + 1.5 g Gistocal (20% Calcium and 10% phosphorus)* per day; divided over 2-3 meals per day.
• At bodyweight of 4 kg: feed 130 g CDD + 50 g cottage cheese + 2 g Gistocal per day
• At body weight of 5 kg: feed about 130 g CDD per day
• At weight of 6 kg : feed about 120 g CDD per day (amounts also depending on activity, body condition etc)

If possible add some lukewarm water through the diet in order to induce extra water intake, so that the urine will be more diluted (aim for s.g. < 1.020). Also check urine pH. If the pH is < 6.6, add potassium citrate to get a urine pH > 7 (potassium citrate dose: ca. 100-150 mg/kg BW divided into 2-3 portions per day)

Monitor urine for crystals of urate and use imaging to check for recurrent stones. If they are still sufficiently small they can be flushed out (urohydropropulsion).

In case of recurrent urate stones, it can also be considered to use allopurinol as additional medication (allopurinol should always be used in combination with a low purine diet, otherwise there is a risk on development of xanthine stones)

* 1 gram of Gistocal can also be replace by 1 gram of CaHPO4.2H20 (calcium phosphate, likely available at the pharmacy).

Note: for pups of other breeds or other age, the exact feeding advice based on supplemented CDD needs to be adapted to meet the nutrient requirement of the individual pup (depending on breed, age and expected adult weight)

In principle the urine pH of dogs fed on CCD should be low enough to prevent the formation of struvite crystals.

So there are several options and questions which should be asked which might explain the presence of (struvite?) crystals in the urine when fed on CCD:

• Was CCD fed exclusively?
• Have they checked if the dog is suffering from a urinary tract infection? In dogs struvite urolithiasis is often associated with the presence of a urinary tract infection. Due to the bacteria in the urine urea in the urine will be split into ammonium and OH-: the result is an increase in urine pH and an increase in the urinary concentration of ammonium – both contributing to the formation of struvite crystals. Even if the dog is on CCD, the initially low urine pH will be increased above 6.4 by the presence of a bacterial infection (at these copnditions struvite can form)
• What kind of crystals are present in the urine. Is it indeed struvite? (then infection is obvious as indicated above). If there are other types of crystals present, then another diet should be recommended.
• Is the dog also suffering from clinical signs related to the urinary tract? Or did they just checked the urine? In that case it is also important how/when the urine was collected and stored. If the urine is stored in the refrigerator, crystals may form. Also when urine samples are stored at room temperature for a longer time, bacteria may start to grow and crystals may form.
• There is also variance in the urine pH during the day. Several hours after a large meal, the urine pH will be higher (post-prandial alkaline tide) which might temporarily enable the precipitation of struvite (soon afterwards urine will be produced with a low pH in which struvite will dissolve)

Struvite stones in dogs are regularly seen to contain a small amount of calcium phosphate. However, pure calcium phosphate uroliths (such as hydroxyapatite, brushite, whitlockite) are uncommon in dogs and are often associated with underlying conditions such as hypercalcemia, hyperparathyroidism and hypervitaminosis D.

Important determinants of the solubility of calcium phosphate:

1. Urine pH. Most calcium phosphate stones typically form in an alkaline medium and are more soluble in an acidic medium. This does not apply to brushite: the solubility of brushite decreases when the urine pH drops.
2. The concentration of calcium (Ca) in the urine: this may be increased due to increased Ca absorption from the bone, increased calcium absorption from the gastrointestinal tract or increased calcium leakage in the kidney
3. The concentration of phosphorus (P) in the urine. Increased P absorption leads to an increased P concentration in the urine
4. Inhibitors of the formation of calcium phosphate (CaP) crystals: e.g. components that bind to components of the crystal (e.g. citrate, which binds calcium and keeps it in solution) or components that disturb the structure of the crystal (e.g. incorporation of magnesium in CaP crystal)
5. Presence of components that promote the precipitation of CaP crystals (e.g. the presence of calcium oxalate crystals promotes the precipitation of CaP)

In case of pure calcium phosphate urolithiasis there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these: 

• Primary hyperparathyroidism
  • As a result of the increased PTH-level, Ca-absorption from bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.
  • Animals with primary hyperparathyroidism can be treated with parathyroidectomy.
    ​
• Other conditions related to hypercalcemia:
  • Hypervitaminosis D
  • Neoplasia
  • Hyperthyroïdism
  • Cushing-syndrome
    ​
• Distal Renal Tubular Acidosis
  • These animals have problems to keep the H+-gradient. The associated hypercalciuria, hyperphosphaturia and hypocitraturia can be treated by alkalization and supplementation with potassium-citrate.
    ​
• Normocalcemic hypercalciuria
  ​Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
    
    The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

Advice for dogs with recurring calcium-containing uroliths

1. Try to detect the cause for the recurrence of the stones (associated conditions?):
   1. Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, Vit D, Mg, urate, blood gasses
   2. Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
   3. Examine urinary tract (X-ray, ultra sound)
      ​
2. Dietary advice:
   1. Increase the urine volume by feeding a wet diet (or add water to a dry diet). It is recommended to keep the specific gravity below 1.020.
   2. Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and less concentrated urine.
   3. For the prevention of hypercalciuria and hyperphosphaturia, a diet with a low level of Ca, Na, P and vit D should be given
   4. (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
   5. Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine
   6. For the reduction of calcium phosphate urolithiasis in dogs we recommend SPECIFIC CKD/CKW Heart & Kidney Support:
      These diets have a reduced level of protein level, Ca, Na, P and the vitamin D level is not extremely high. For small dogs it advised to give CKW, for large breed dogs, the urine volume can be increased by adding extra water to CKD.

Additional advices:

• Avoid drugs that can increase the urinary calcium excretion (e.g. glucocorticosteroids, furosemide, acetazolamide)
• Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3 portions per day

Taking into account the presence of food allergy and calcium oxalate urolithiasis the hypoallergenic SPECIFIC CDD Food Allergy Management would be the best option for this dog as the reduced protein level in the diet and the induction of a higher urinary pH will reduce the risk on calcium oxalate (a reduced protein level will reduce the supply of amino acids glycine which can be metabolised into oxalate). For further reduction on the risk on recurrence of Ca-ox, it is recommended to promote the water intake of the dog by adding extra hand-warm water to the diet (feeding as a ‘diner’ type of diet).

As indicated in the product book, CCD is not suited for pups. This is because the protein level and the level of minerals is too low for pups.

The good thing is that struvite stones in dogs and especially pups are generally secondary to a urinary tract infection (UTI), so if the UTI can be successfully treated with antibiotics, it will generally not be needed to continue to feed an anti-struvite diet for a long time (only for the period required to dissolve a stone / crystals).

An alternative for growing pups with struvite problems is to start to feed FCD or FCD-L, since this has a somewhat higher mineral level compared to CCD (although still reduced compared to requirements)  and a protein level which meets the requirement of pups.  FCD-L is slightly higher in minerals than FCD and may therefore be the best choice

For the feeding advice for FCD-L for pups: just follow the feeding recommendation for pups as listed in the feeding table for CPD-S/M or CPD-XL and multiply with 1.09 (CPD-S/M) or 1.03 (CPD-XL) to get the feeding advice for FCD-L

It is recommended to follow up closely and to treat the UTI simultaneously - as soon as the UTI is under control and struvite crystals have disappeared, the dog can just be switched back to a normal puppy diet in order to keep the period on the anti-struvite diet restricted (continue to monitor urine, especially for UTIs)

note:

The FEDIAF recommendation for calcium and P in pups is:

• 0.60 g Ca/MJ and 0.54 g P/MJ for pups < 14 weeks of  age
• 0.48 g Ca/MJ and 0.42 g P/MJ for pups > 14 weeks of age
•  

The mineral level in FCD-L is 0.45 g Ca/MJ and 0.41 g P/MJ

Since pups will probably be on FCD-L for only a short time (until the UTI is controlled and struvite crystals have disappeared), pups of most breeds will be able to cope with this lower mineral level

Only in case the pup is very young, from a breed very sensitive to skeletal problems or fed FCD-L for a very long time, it could be considered to supplement with some extra calcium and phosphorus

(be careful with dosing, as phosphorus is a component of struvite and giving too much P-supplement might increase the risk on struvite formation). Calcium and phosphorus could be supplemented through the mineral supplement Gistocal (containing 20% calcium and 10% phosphorus):

2 grams of Gistocal added to 100 g FCD-L will increase the Ca and P level to recommended FEDIAF levels for pups < 14 weeks of age

0.2 gram of Gistocal added to 100 g FCD-L will increase the Ca and P level to recommended FEDIAF levels for pups > 14 weeks

CCD Struvite Management is a complete diet for adult dogs (meeting the FEDIAF recommendations for adult dogs for most nutrients. Only protein, Ca, P and Mg are slightly below the FEDIAF recommendation for healthy adult dogs with a low energy intake, but the levels are above NRC minimum requirements and sufficiently high to maintain  mineral and protein balance).

On the packaging it is indicated that CCD can be given for 5-12 weeks for dissolution of struvite stones and initially for 6 months for reduction of recurrence of struvite. The indication for the time of use, as indicated on the label of SPECIFIC Special Care (dietetic) diets, is mandatory according the EU legislation for therapeutic diets (R 2020/354). The legal declaration of the recommended period of use indicates a range of time within which the nutritional purpose should normally be achieved. The purpose of this legal indication is that after this period a vet evaluates how the dog/cat is doing on the diet and based on that will decide to continue the feeding of the diet or not. If the dog/cat is doing fine on the diet it can be fed long term on the diet.

(Just as for all cats and dogs on any diet, it is recommended to monitor the pet's health and nutritional status on a regular basis, and adapt the diet if the nutritional assessment indicates that the diet should be adapted due to changes in the pet's condition or presence of concurrent clinical conditions).

Please be aware that in dogs struvite urolithiasis is in almost all cases the result of a urinary tract infection (UTI). In case of a UTI the most important treatment is treatment with the proper antibiotics. The role of the diet is to dissolve existing stones / crystals.
After the clinical signs have disappeared, the stones/ crystals dissolved and the UTI successfully treated, the management of recurrence of infection-induced struvite is monitoring for new UTI’s and immediate treatment of them. It is not needed to keep the dog on an anti-struvite diet long-term.
In dogs with recurrent UTI’s is recommended to check for underlying causes.

Please see attached paper on the ACVIM consensus on management of urolithiasis (Lulich et al 2016), point 3.2, indicating that it is not necessary to feed an anti-struvite diet long-term for reduction of recurrence of infection-induced struvite urolithiasis in dogs.   

Struvite urolithiasis (precipitation of magnesium ammonium phosphate in the lower urinary tract) is promoted by high concentrations of magnesium, ammonium and phosphate in the urine and the presence of an alkaline urine pH.

In the vast majority of dogs with struvite urolithiasis, struvite formation is the result of a urinary tract infection. During an infection with urease-positive bacteria, urea in the urine will be converted into ammonium, with the urine pH also rising. The increase in the ammonium concentration and urinary pH will then give rise to the precipitation of struvite.

The primary treatment for struvite urolithiasis in combination with a urinary tract infection is to provide an appropriate antibiotic treatment. In addition, it is recommended to provide an appropriate diet to dissolve the stone or any crystals that are still present and to prevent the formation of struvite.

The guidelines for a diet for solution / reduction of recurrence of struvite in the dog are the following:

• A decrease in urinary pH within the range of 6.0 - 6.5 to dissolve struvite.
• A reduction in the magnesium and phosphorus content in the diet in order to reduce the urine concentration of these components of struvite.
• A reduction in dietary protein content to limit the amount of urea in the urine that can be converted into ammonium by urease-positive bacteria.
• An increase in dietary sodium to increase urine volume.

In addition to the above-mentioned specific guidelines for the prevention of struvite formation, the general advice is also to reduce crystal formation by giving the dog a lot of water through the diet. This will increase the urine volume and make the urine less concentrated. It is recommended to keep the specific gravity below 1.020. Increased water intake can be achieved by giving the dog a wet food or by soaking dry kibbles in water.

The diet we recommend for management of struvite urolithiasis in dogs is: SPECIFIC CCD

SPECIFIC Struvite Management (dry anti struvite diet for dogs) is prescribed to dissolve struvite stones and reduce recurrence. This diet is very tasty and meets the above guidelines.

It is recommended to regularly check for the presence of urinary tract infections, crystals or stones. When recurrence of urinary tract infections can be prevented, long-term provision of SPECIFIC Struvite Management is generally not necessary.

Calcium oxalate urolithiasis is promoted by high concentrations of calcium and oxalate in the urine. Existing calcium oxalate stones cannot be dissolved and must be surgically removed. A diet is recommended to prevent recurrence.

The guidelines for a diet to reduce calcium oxalate crystals in the dog are the following:

• A low protein content in the diet, because the amino acid glycine is a precursor of oxalate.
• An induction of a urine pH between approx. 6.5 and 7.5 because an excessively acidic urine could cause calciuria.
• Low sodium in the diet to prevent calciuria.

In addition to the above-mentioned specific guidelines for the reduction of calcium oxalate formation, the general advice is also to prevent crystal formation by giving the dog plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water intake can be achieved by feeding the dog a wet food (alutray) or soaking dry kibbles in water.

It is further advised to monitor regularly for urine pH, presence of crystals, urinary tract infection and any new stones. If the urine pH is below 6.5, potassium citrate can be given to slightly increase the urine pH. The advice is to keep the specific gravity of the urine below 1.020.

With recurrent calcium oxalate stones, it is advisable to investigate whether there are underlying causes for a disturbance in the calcium balance that can be treated (see appendix).

The diets that we recommend for calcium oxalate urolithiasis in dogs: SPECIFIC CKD/CKW

SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended to reduce recurrence of calcium oxalate stones in the dog. These dog kidney diets are also suitable for the reduction of calcium oxalate stones due to the reduced protein and sodium content and the induction of the higher urinary pH.

Potentially, potassium citrate can help make the urine alkaline and keep calcium and oxalate in solution. The guideline is a urine pH between 6.5 and 7.5. Starting dose 2 times 50-75 mg / kg.

The dose is a starting dose and good monitoring / adjustment is desired. (pH guided, 2 weekly monitoring)

APPENDIX

Conditions related to calcium-containing uroliths

In case of recurrent calcium-containing uroliths, there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these. 

• Primary hyperparathyroidism
  As a result of the increased PTH-level, the Ca-absorption from the bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 Vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.
  Animals with primary hyperparathyroidism can be treated with parathyroidectomy.
   
• Other conditions related to hypercalcemia:
  • Hypervitaminosis D
  • Neoplasia
  • Hyperthyroïdism
  • Cushing-syndrome
     
• Distal Renal Tubular Acidosis
  These animals have problems keeping the H+-gradient. The associated hypercalciuria, hyperfosfaturia en hypocitraturia can be treated by alkalization and supplementation with K-citrate.
   
• Normocalcemic hypercalciuria
  ​Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
    
    The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

Advice for dogs and cats with recurring calcium-containing uroliths

• Try to detect the cause for the recurrence of the stones (associated conditions?):
  • Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, Vit D, Mg, urate, blood gasses
  • Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
  • Examine urinary tract (X-ray, ultra sound)
    ​
• Dietary advice:
  • Increase the urine volume by feeding a wet diet (or add water to a dry diet)
  • Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and a less concentrated urine.
  • For the prevention of hypercalciuria and hyperphosphaturia, a diet with a low level of Ca, Na, P and vit D should be given
  • (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
  • Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine
    ​
• Additional advice:
  • Avoid drugs that can increase the urinary calcium excretion (e.g. glucocorticosteroids, furosemide, acetazolamide)
  • Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3- portions per day.

Ammonium urate urolithiasis is promoted by high concentrations of ammonium and urate in the urine and a low urine pH. In healthy animals, purines (from DNA) are converted into allantoin. In Dalmatian dogs and in animals with impaired liver function or liver shunt, purines are not converted to allantoin, but to urate.

The guidelines for a diet for solution / reduction of recurrence of ammonium urate are the following:

• The use of low-purine raw materials, such as eggs, milk products and rice.
• A low protein content in the diet to reduce the supply of purines and decrease the ammonium content in the urine.
• The induction of a urinary pH in the range of 6.5-7.5 to promote urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of urate formation, the general advice also applies to giving the dog plenty of water through the diet, in order to prevent crystal formation. This will increase the urine volume and make the urine less concentrated. It is recommended to keep the specific gravity of the urine below 1.020. Increased water intake can be achieved by feeding the dog a wet food (alutray) or soaking dry kibbles in water.

The diets we recommend for dogs with urate urolithiasis: SPECIFIC CDD or CKD / CKW

SPECIFIC Food Allergen Management (CDD) is the first choice to prescribe for the management and reduction of recurrence of urate stones in the dog. This dry hypoallergenic dog food is based on egg and rice (low purine!) and fully complies with the above guidelines.

As a second choice, SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended. These diets are not exclusively made from low-purine raw materials, but are suitable for the reduction of urate stones due to the reduced protein (and thereby purine) content and the induction of a higher urine pH.

Regularly check the urine pH, specific gravity and the presence of crystals or stones. When the urine pH is too low, potassium citrate can be given to increase the urine pH. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired).
Since urate stones (except in Dalmatian dogs) are often caused by hepatic impairment, it is recommended that the liver function of the dog be monitored. In animals with recurrent urate stones, allopurinol can be provided in addition to a diet.

Xanthine stones are relatively rare in the dog. Xanthine is a product of the breakdown of purines (which are found in DNA). In healthy dogs, purines are converted into allantoin, a substance that is highly water-soluble and is excreted in the urine without any problems. In dogs, a hereditary abnormality can occur in which a deficiency of the enzyme xanthine oxidase is present. As a result, the dog will convert purines to xanthine. Xanthine is not very soluble in water and xanthine stones will be formed if urine concentrations of xanthine are too high, especially at a low urine pH.

In addition, xanthine stones in dogs can also result from the treatment of urate stones or Leishmania with allopurinol. Both urate and xanthine are breakdown products of purines. Allopurinol inhibits the activity of the enzyme xanthine oxidase. If urate stones are treated with allopurinol, but at the same time many purines remain available through the diet, the dog will not form urate stones, but xanthine stones. It is therefore important to prescribe a special low-purine diet when using allopurinol.

The guidelines for a diet for reduction of xanthine (and urate) are the following:

• The use of low-purine raw materials, such as eggs, milk products and rice.
• A low protein content in the diet to reduce the supply of purines.
• The induction of a urinary pH in the range of 6.5-7.5 to promote xanthine and urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of xanthine and urate formation, the general advice also applies to giving the dog plenty of water through the diet, in order to prevent crystal formation. This will increase the urine volume and make the urine less concentrated. It is recommended to keep the specific gravity below 1.020. Increased water intake can be achieved by feeding the dog a wet food (alucup) or soaking dry kibbles in water.

The diets we recommend for dogs with xanthine urolithiasis: SPECIFIC CDD or CKD / CKW

SPECIFIC Food Allergen Management (CDD) is the first choice to prescribe for the management and reduction of recurrence of xanthine stones in the dog. This dry hypoallergenic dog food is based on egg and rice (low purine!) and fully complies with the above guidelines.

As a second choice, SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended. These diets are not exclusively made from low-purine raw materials, but are suitable for the reductoin of xanthine stones due to the reduced protein (and thereby purine) content and the induction of a higher urine pH.

Regularly check the urine pH and the presence of crystals or stones. When the urine pH is too low, potassium citrate can be given to increase the urine pH. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired).

Cystine urolithiasis is promoted by a high urinary cystine concentration and a low urinary pH. Cystine is made in the body from the sulfur-containing amino acids cysteine ​​and methionine and is reabsorbed from the pre-urine in the renal tubuli.  Due to a hereditary defect, some animals reabsorb less cystine and urinary cystine levels are increased. Existing cystine stones can be dissolved through an adjusted diet and use of medication (2-mercatopropionyl glycine, MPG). A diet is recommended to prevent recurrence.

 The guidelines for a diet for the reduction of cystine urolithiasis in dogs are the following:

• A low protein content in the diet, because it contains less cysteine ​​and methionine. Therefore less cystine will be excreted in the urine and less cystine stones can be formed.
• An induction of a urinary pH > 7.5 to increase the solubility of cystine.
• A moderate sodium content to limit cystine secretion.

In addition to the above-mentioned specific guidelines for the reduction of cystine urolithiasis, the general advice is also to prevent crystal formation by giving the dog plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water intake can be achieved by giving the dog a wet food (alucup) or by soaking the dry kibble in water.

The diet we recommend for management of cystine urolithiasis in dogs: SPECIFIC CKD / CKW

SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended for dissolution and reduction of recurrent cystine stones in dogs. These kidney diets are very tasty and suitable for the reduction of recurrence of cystine stones due to the reduced protein and sodium content and the induction of a higher urinary pH.

Optionally, 2-mercaptopropionyl glycine (MPG) can be given as a support drug. In the dissolving phase, the dosage twice daily is 15-20 mg / kg, and preventively 15 mg / kg twice daily.

Male castration can reduce the risk of recurrence.

Regular monitoring is recommended, aiming for an SG of the urine <1.020 and a urine pH> 7.5. If necessary, potassium citrate can be given to raise the urine pH> 7.5.

The incidence of silicate stones in the dog is low (about 1% of all stones in the urinary tract). The stones often consist of 100% silicate; however, there are also stones in which silicate occurs in combination with calcium oxalate. In the presence of an infection, the combination with struvite can also develop.

Most silicate stones have a very remarkable appearance: they are spherical with all around protuberances (rounded "spines"). The size of silicate stones can vary from 1 mm to 3 cm. Dogs often have multiple silicate stones (up to 30 pieces) in the urinary tract.

Silicate / Silicon (Si) is the main component of sand, quartz and stone. Some plants are rich in silica. It is believed that some forms of silica can be absorbed through the gastrointestinal tract and excreted through the urine.

Little is known about the origin of silicate stones in the dog. It is believed that eating sand and stones (pica) and eating feeds with high silica contents can cause silicate stones to form in dogs. In particular, feeds with a lot of vegetable material that are rich in silicates (such as the hulls of rice and soybeans) are suspected. In addition, certain medications or supplements may contain silica as a carrier. The use of these medications or supplements in dogs with silicate stones is not recommended.

Silicate stone reduction

A study showed that 13% of dogs with silicate stones have relapses within 1 to 5 years. The following is therefore recommended to reduce recurrence:

• Pica
  Check whether the dog regularly eats materials such as sand, stones or compost. Eating some silica-rich plants (certain grasses) should also be avoided.
• Urine volume
  For the prevention of all types of stones it is important to increase the urine volume, so that urine concentrations of the components of the stone are reduced and the frequency of urination is increased. It is recommended to keep the specific gravity below 1.020. The most effective way to increase the volume of urine is to give wet food (alutray). In addition, it is also possible to give dry food soaked in water. It is not recommended to add extra salt (NaCl) to the diet, because this increases the risk on calcium oxalate formation (which often occurs in combination with silicate stones).
• Urine pH
  Silicate stones are less soluble in an acidic environment. It is therefore recommended to give a food that produces a neutral to alkaline urine pH.
• Urinary tract infections
  To prevent the formation of infection-caused struvite stones, it is recommended to administer antibiotics after surgical removal of silicate stones.

The diet we recommend for management of silica urolithiasis in dogs: SPECIFIC CKD / CKW

SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended for the reduction of recurring silicate stones in the dog. These kidney diets are very tasty and due to the absence of silica-rich ingredients and the induction of the higher urinary pH, they are suitable for the prevention of silicate stones.

A stone with a combination of calcium oxalate, struvite and calcium phosphate usually forms as a calcium oxalate stone. This stone causes irritation of the bladder, which makes it more sensitive to an infection. During an infection with urease-positive bacteria, urea in the urine will be converted into ammonium. During this conversion, the urine pH will also rise. The increase in the ammonium concentration and the urinary pH will then give rise to the precipitation of struvite and possibly calcium phosphate. This will results in a combined stone with a core of calcium oxalate, covered by a struvite / calcium phosphate shell.

Combined stones with calcium oxalate, struvite and calcium phosphate cannot be dissolved and must be surgically removed. The reduction of recurrence is directed against the type of crystal that is in the core of the stone (initial problem = calcium oxalate). In addition, it is important that the infection is treated with suitable antibiotics.

The guidelines for a diet to reduce calcium oxalate urolithiasis in the dog are the following:

• Low protein in the diet, because the amino acid glycine is a precursor of oxalate.
• An induction of a urine pH between 6.5 and 7.5 because an excessively acidic urine could cause calciuria.
• Low sodium in the diet to prevent calciuria.

In addition to the above-mentioned specific guidelines for the reduction of calcium oxalate formation, the general advice is also to prevent crystal formation by giving the dog plenty of water through the diet. This will increase the urine volume and make the urine less concentrated. Increased water intake can be achieved by giving the dog a wet food (alucup) or by soaking dry kibbles in water.

It is further advised to monitor regularly for urine pH, presence of crystals, urinary tract infection and any new stones. If the urine pH is below 6.5, potassium citrate can be given to slightly increase the urine pH. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired). The advice is to keep the specific gravity of the urine below 1.020.

In case of recurrent calcium oxalate stones, it is recommended to investigate whether there are underlying causes for a disturbance in the calcium balance that can be treated (see appendix).

The diet we recommend for management of combined struvite, calcium oxalate, calcium phosphate urolithiasis in dogs: SPECIFIC CKD / CKW

SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended to reduce recurrence of calcium oxalate stones in the dog. These dog kidney diets are very tasty and meet the above guidelines. These diets are also suitable for the prevention of calcium oxalate / calcium phosphate stones due to the reduced protein, sodium and phosphorus content and the induction of the higher urinary pH.

APPENDIX

Conditions related to calcium-containing uroliths

In case of recurrent calcium-containing uroliths, there can be underlying causes, like abnormalities in the calcium metabolism, which can predispose to the formation of calcium containing uroliths. It is therefore recommended to check for underlying causes and, if possible, to manage these. 

• Primary hyperparathyroidism
  As a result of the increased PTH-level, the Ca-absorption from the bone will increase as well as the renal tubular reabsorption of Ca. More 1,25 Vitamin D will be formed and the absorption of Ca from the gut will increase. As a result, the Ca level in the plasma will increase, resulting in increased filtration of Ca in the glomeruli and increased Ca-excretion in the urine.
  Animals with primary hyperparathyroidism can be treated with parathyroidectomy.
   
• Other conditions related to hypercalcemia:
  • Hypervitaminosis D
  • Neoplasia
  • Hyperthyroïdism
  • Cushing-syndrome
    ​
• Distal Renal Tubular Acidosis
  These animals have problems keeping the H+-gradient. The associated hypercalciuria, hyperfosfaturia en hypocitraturia can be treated by alkalization and supplementation with K-citrate.
   
• Normocalcemic hypercalciuria
  ​​Generally, there are 2 possible causes for normocalcemic hypercalciuria:
  • Absorptive hypercalciuria: an increased absorption of Ca from the GI tract
  • Renal Ca-leakage: there is a disturbed capacity in the reabsorption of Ca from the proximal tubuli
    
    The difference between these 2 possible causes can be determined by analysis of the urinary calcium excretion after fasting: animals with renal Ca-leakage can be treated with thiazide diuretics (2-4 mg hydrochloric thiazide per kg BW per 12 hours) (NB This should not be given to animals with absorptive hypercalciuria!)

Advice for dogs and cats with recurring calcium-containing uroliths

1. Try to detect the cause for the recurrence of the stones (associated conditions?):
   1. Blood test: urea, creatinine, Ca, P, Na, K, Cl, PTH, Vit D, Mg, urate, blood gasses
   2. Urine test: pH, crystals, 24-hour urine: volume, creatinine, Ca, P, Mg, citrate, oxalate
   3. Examine urinary tract (X-ray, ultra sound)
2. Dietary advice:
   1. Increase the urine volume by feeding a wet diet (or add water to a dry diet)
   2. Give a diet with a low protein level: this will lead to a urine with a lower Ca and P level and a less concentrated urine.
   3. For the prevention of hypercalciuria and hyperphosphaturia, a diet with a low level of Ca, Na, P and vit D should be given
      (NB an increased Na-intake is associated with increased urinary Ca excretion; and increased vit D intake as well)
   4. Aim for a diet inducing a neutral – alkaline pH: a low urine pH can increase the calcium excretion in the urine
      ​

• Additional advice:
  • Avoid drugs that can increase the urinary calcium excretion (e.g. glucocorticosteroids, furosemide, acetazolamide)
  • Supplementation with potassium citrate will keep calcium salts in solution. Advised dose: 100-150 mg/kg BW/day, divided into 2-3- portions per day.

For combined stones composed of struvite and urate, it is recommended to direct the reduction of recurrence on the reduction of urate formation. Urate urolithiasis is promoted by high concentrations of urate in the urine and a low urine pH. In healthy animals, purines (from DNA) are converted into allantoin. In Dalmatian dogs and in animals with impaired liver function or liver shunts, purines are not converted to allantoin, but to urate.

The guidelines for a diet for solution / reduction of ammonium urate are the following:

• The use of low-purine raw materials, such as eggs, milk products and rice.
• A low protein content in the diet to reduce the supply of purines and decrease the ammonium content in the urine.
• The induction of a urinary pH in the range of 6.5-7.5 to promote urate solubility.

In addition to the above-mentioned specific guidelines for the reduction of urate formation, the general advice also applies to giving the dog plenty of water through the diet, in order to prevent crystal formation. This will increase the urine volume and make the urine less concentrated. It is recommended to keep the specific gravity of the urine below 1.020. Increased water intake can be achieved by feeding the dog a wet food (alucups) or soaking dry kibbles in water.

The struvite formation can result from a bacterial urinary tract infection. It is therefore advised to check for the presence of a urinary tract infection and, if present, to treat it with antibiotics.

The diets we recommend for dogs with combined struvite-urate urolithiasis: SPECIFIC CDD or CKD / CKW

SPECIFIC Food Allergen Management (CDD) is the first choice to prescribe for the management and reduction of recurrence of urate stones in the dog. This dry hypoallergenic dog food is based on egg and rice (low purine!) and fully complies with the above guidelines.

As a second choice, you can also prescribe SPECIFIC Heart & Kidney Support (CKD / CKW). These diets are not exclusively made from low-purine raw materials, but are suitable for the reduction of recurrence of urate stones due to the reduced protein (and thereby purine) content and the induction of a higher urine pH.

Regularly check the urine pH, specific gravity and the presence of crystals, stones or urinary tract infection. When the urine pH is too low, potassium citrate can be given to increase the urine pH. Starting dose is 2 times 50-75 mg / kg BW (2 weekly monitoring and pH guided adjustment is desired). Since urate stones (except Dalmatian dogs) are often caused by hepatic impairment, it is recommended that the liver function of the dog be monitored. In animals with recurrent urate stones, allopurinol can be provided in addition to a diet.

The incidence of silicate stones in the dog is low (about 1% of all stones in the urinary tract). The stones often consist of 100% silicate, but when this stone irritates the bladder, a urinary tract infection can develop. During an infection with urease-positive bacteria, urea in the urine will be converted into ammonium. During this conversion, the urine pH will also rise. The increase in the ammonium concentration and urinary pH will then give rise to the precipitation of struvite. This will create a combined stone with a core of silicate, encased in a mantle of struvite.

Combined stones consisting of silicate and struvite cannot be dissolved and must be surgically removed. The reduction of recurrence is directed against the type of crystal that is in the core of the stone (initial problem = silicate). In addition, it is important that the infection is treated with suitable antibiotics.

Silicate / Silicon (Si) is the main component of sand, quartz and stone. Some plants are rich in silica. It is believed that some forms of silica can be absorbed through the gastrointestinal tract and excreted through the urine.

Little is known about the origin of silicate stones in the dog. It is believed that eating sand and stones (pica) and eating feeds with high silica contents can cause silicate stones to form in dogs. In particular, feeds with a lot of vegetable material that are rich in silicates (such as the hulls of rice and soybeans) are suspected. In addition, certain medications or supplements may contain silica as a carrier. The use of these medications or supplements in dogs with silicate stones is not recommended.

Silicate stone reduction

A study showed that 13% of dogs with silicate stones have relapses within 1 to 5 years. The following is therefore recommended to prevent recurrence:

• Pica
  Check whether the dog regularly eats materials such as sand, stones or compost. Eating some silica-rich plants (certain grasses) should also be avoided.
• Urine volume
  For the prevention of all types of stones it is important to increase the urine volume, so that urine concentrations of the components of the stone are reduced and the frequency of urination is increased. It is recommended to keep the specific gravity below 1.020. The most effective way to increase the volume of urine is to give wet food (alucup). In addition, it is also possible to give dry food soaked in water. It is not recommended to add extra salt (NaCl) to the diet, because this increases the risk on calcium oxalate formation (which often occurs in combination with silicate stones).
• Urine pH
  Silicate stones are less soluble in an acidic environment. It is therefore recommended to give a food that produces a neutral to alkaline urine pH.
• Urinary tract infections
  To prevent the formation of infection-caused struvite stones, it is recommended to administer antibiotics after surgical removal of silicate stones.

The diets we recommend for management of combined silica/struvite urolithiasis in dogs: SPECIFIC CKD / CKW

SPECIFIC Heart & Kidney Support (CKD / CKW) is recommended for the reduction of recurring silicate stones in the dog. These kidney diets are very tasty and due to the absence of silica-rich ingredients and the induction of the higher urinary pH, they are suitable for the prevention of silicate stones. It is recommended to monitor on a regular basis for the presence of urinary tract infections or crystals or uroliths.