Interview with Dr Delisa Appleton of Hill’s Pet Nutrition on Urinary Care

Lower urinary tract conditions are common in dogs and cats and nutrition plays an integral role in their management and reducing recurrence. 

Top urinary conditions in dogs

Globally in 2022, the most common urolith type was Struvite (40%), followed by Calcium Oxalate (33%), Purine (5%) and Cystine (7%)¹

Top urinary conditions in cats

Studies indicate that feline interstitial cystitis (FIC) is the number one form of lower urinary tract disease (LUTD) in cats < 10 years old (55%), followed by urethral plugs (16%) and uroliths (15%)²

Globally in 2022, the most common urolith type in cats was Struvite (50%), followed by Calcium Oxalate (37%)¹. 

Are there any predispositions when it comes to urinary problems in cats/dogs

Dogs

Struvite uroliths appear to be more common in female or immature dogs. They commonly occur secondary to a urinary tract infection with a urease-producing microbe such as Staphylococcus, Proteus spp. or Ureaplasma. These microbes both increase the urinary pH and some of the precursors for struvite (ammonium and phosphate), which in turn may lead to crystal and urolith formation. 

If stuvite uroliths are diagnosed in a young puppy, it’s a good idea to look for pre-existing anatomical issues such as a patent urachus or ectopic ureters which may be the reason for developing a UTI and subsequent struvite stones. In an adult female dog, look for anatomical reasons why she may be getting a UTI such as peri-vulval dermatitis, hooded vulva, prominent vulval folds, incontinence etc.  Also look for concurrent diseases such as Chronic Kidney Disease or Diabetes Mellitus. 

If you have an entire male dog with struvite uroliths they are still usually secondary to a urinary tract infection – possibly ascending from a prostatitis.

Calcium oxalate is more common in older, male dogs. It’s important to check ionised calcium to ascertain whether they are hypercalcaemic. If they are, look for reasons for this such as neoplasia, hyperadrenocorticism etc.   

Urate uroliths are common in Dalmatians and English Bulldogs associated with a heritable gene alteration leading to increased uric acid excretion in the urine¹. 

Younger dogs of other breeds (e.g. Shiz Tzu, Pug, Jack Russel, Dachshund, Bichon Frise, Chihuahua), with urate uroliths should be assessed for the presence of a portovascular anomaly such as a portosystemic shunt or microvascular dysplasia (bile acids, ultrasound of the liver), while older dogs with urate uroliths may have liver disease.

Cystine is common in English Bulldogs, Border Collies, Dachshunds, French Bulldogs and Staffordshire Terriers¹.

Some breeds have androgen dependent cystine uroliths such as English Bulldogs, French Bulldogs, Mastiffs, Staffy’s and other breeds. In these cases castration can reduce or even resolve the problem once the stones are removed. 

Cats

Risk factors for FIC in cats include living in a multi-cat household, being overweight or obese, conflict with other cats/animals, being male and use of non-clumping litter. Also, lack of environmental enrichment and play²

Think calcium oxalate uroliths in Burmese, Ragdoll, Birman,  Persians etc. 

While much less common, think urate uroliths in Siamese, Devon Rex, Birman and Egyptian Mau. 

Key urinary health preventative steps

Dogs with a history of Struvite or Calcium Oxalate

• The key to preventing recurrence of struvite in dogs is to control urinary tract infections and to treat with an appropriate antibiotic based on culture and sensitivity. 
• To dissolve struvite or to help prevent recurrence of struvite or calcium oxalate, feed Hill’s Prescription Diet c/d Multicare or Hill’s Prescription Diet c/d Multicare + Metabolic.
• The nutrition in Hill’s Prescription Diet c/d Multicare or c/d Multicare + Metabolic have controlled levels of magnesium, calcium and phosphorus to reduce the building blocks of crystals and uroliths, added potassium citrate to help inhibit calcium oxalate crystals and uroliths (by binding to calcium to create soluble calcium citrate) as well as an optimal urinary pH which discourages struvite formation with minimal effect on calcium oxalate formation.  Increased levels of omega-3 fatty acids help break the inflammatory cycle associated with uroliths and crystals.
• Hill’s Prescription Diet c/d Multicare + Metabolic Canine is clinically proven nutrition to reduce body weight by 13% in 60 days and can be fed long-term after achieving successful weight loss⁴.

Cats with FIC 

• Hill’s Prescription Diet c/d Multicare or Hill’s Prescription Diet c/d Multicare Stress or Hill’s Prescription Diet c/d Multicare Stress + Metabolic (if overweight or obese). All of these foods are available in a variety of wet foods as well including mince, stews and pouches.
• The nutrition in these foods has been shown to decrease the recurrence of FIC clinical signs by 89%³. In addition, Hill’s Prescription Diet c/d Multicare Stress or Hill’s Prescription Diet c/d Multicare Stress + Metabolic contain hydrolysed casein and L-tryptophan to help manage stress and stress-related behaviours.
• Aim for urine specific gravity of  < 1.030 – increase wet food, water fountains, flavour water etc 
• Litter box management –size, shape, location. One for each cat and a spare. One on every level of a multi-story house
• A pheromone diffuser, for example Feliway®
• Manage inter-cat aggression. Put a bell on the aggressor
• Toys and play – chasing and pouncing

• fishing pole with feathers, 

• Ability to climb, scratch, hide, rest
  • scratching poles, perching areas, cardboard boxes

Cats with a history of Struvite or Calcium Oxalate Uroliths 

• Hill’s Prescription Diet c/d Multicare or Hill’s Prescription Diet c/d Multicare Stress or Hill’s Prescription Diet c/d Multicare Stress + Metabolic (if overweight or obese).  All of these foods are available in a variety of wet foods as well including mince, stews and pouches.
• Aim for urine specific gravity of  < 1.030 – increase wet food, water fountains, flavour water etc 

• Ensure pH is 6.0-6.5 
• For calcium oxalate formers, check ionised calcium levels – the cat may be hypercalcaemic and although many of these are idiopathic, other causes include chronic kidney disease or steroid administration.

Cats with a history of urethral plugs

• If a cat has a history of urethral plugs with mineral associated, 96% of these will be struvite¹. 
• Recommend Hill’s Prescription Diet c/d Multicare or Hill’s Prescription Diet c/d Multicare Stress or Hill’s Prescription Diet c/d Multicare Stress plus Metabolic (if overweight or obese)

Recommended urinary testing in wellness consultations

For puppies it’s important to check for evidence of any anatomical issues that may increase the risk of getting infection and hence struvite crystals or uroliths. If uroliths are identified in immature dogs they are usually struvite but could also be urate secondary to a portovascular anomaly.  Ideally, a urinalysis should be performed at each annual checkup or 6 monthly for senior pets. 

Diagnostics and workups for potential urinary health conditions

If the pet is showing urinary clinical signs a minimum database should include a urinalysis, imaging and if a bacterial infection is suspected, then a culture and sensitivity should be performed. Be sure to include the entire urinary tract so as not to miss uroliths in the urethra.

Performing a urinalysis on a first-morning urine sample, before the patient has eaten and within 30 minutes of voiding helps avoid many in vitro changes that may occur including changes in pH, USG and crystals may come in or out of solution. 

For example, as the urine cools crystals may come out of solution. Eating can induce a post-prandial alkaline tide hence the pH may be higher than expected. If the sample is allowed to evaporate the USG may increase. 

Key pet owner education around urinary health

It is important to educate pet owners about what to look for that may indicate a urinary issue or infection.

Explain to them that inappropriate urination maybe the only sign but also to act quickly if there is evidence of stranguria, dysuria or haematuria. Owners may think their cat is constipated if it is straining in the litter box but of course, this can be a life threatening blockage.  Litter box management (as above for cats with FIC), is also important to ensure cats are happy to urinary and don’t retain urine for longer periods. 

For dog owners, educating owners about the subtle signs of a UTI such as an increase in frequency of urination or licking the vulva/prepuce. 

One of the key risk factors in both dogs and cats is being overweight or obese so having the conversation about keeping their pet trim through life or losing weight if already overweight is paramount. 

Stress often plays a role in FIC. Chronic stress leads to an abnormal stress response leading to bladder inflammation. The cat then perceives pain, which leads to more stress. The end result is a vicious cycle that repeats itself. The key point to remember is that stress affects the urinary bladder and the brain – and treatment strategies should be aimed at both areas to increase success of managing cats with FIC. Refer to the section above on urinary health preventative steps for tips around multimodal behavioural enrichment strategies for these cats. 

The role of nutrition in urinary health

There are many factors involved in crystal and uroliths formation and nutrition is a key method that we can use to reduce the risk of occurrence or recurrence of uroliths. 

For instance, the S+OXSHIELD seal indicates that a Hill’s Prescription Diet is formulated to meet specific nutrient standards, shown to promote a urinary environment that helps reduce the risk for struvite and calcium oxalate crystals. This means that even if a pet needs to be on Prescription Diet for another medical reason e.g. skin disease, kidney disease etc, that food also helps reduce the risk of struvite or calcium oxalate crystals forming.

If a dog or cat develops uroliths, nutrition is integral in both dissolving certain types and reducing the risk of recurrence of all types. For example, Hill’s Prescription Diet c/d Multicare dissolves struvite and helps prevent recurrence of both struvite or calcium oxalate uroliths while Hill’s Prescription diet u/d  may help dissolve urate uroliths and helps prevent recurrence of both urate  or cystine. 

References 

1. 2022 Minnesota Urolith Center Global Data, 2022. Generated by Minnesota Urolith Center, March 2023,z.umn.edu/2022GlobalUrolith. Accessed July 2023.
2. Lekcharoensuk C, Osborne CA, Lulich JP. Epidemiologic study of risk factors for lower urinary tract diseases in cats. J Am Vet Med Assoc. 2001;218(9):1429-1435.
3. Kruger JM, Lulich JP, MacLeay J, et al. Comparison of foods with differing nutritional profiles for long-term management of acute nonobstructive idiopathic cystitis in cats. J Am Vet Med Assoc. 2015;247(5):508-517
4. Floerchinger AM, Jackson MI, Jewell DE et al. Effect of feeding a weight loss food beyond a caloric restriction period on body composition and resistance to weight gain in dogs. J Am Vet Med Assoc 2015;247:375–384.

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