Vet Speak: A delicate problem for cats that needs immediate attention
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ABBY was a long-haired tabby who had been brought into the surgery as she had been passing small pools of urine throughout the house and also been back and forth, trying to pass urine in her litter tray, writes Vet Alison Laurie-Chalmers.
She was otherwise bright, active and eating well, but clearly had a urinary tract problem.
Samples were obtained using a clever, non-absorbent, cat litter tray sand and examination showed she had a lot of crystals developing within her urine. Her condition was termed urolithiasis, a medical term referring to the presence of crystals or stones within the urinary tract.
Feline urine is a complex solution in which salts, such as struvite (magnesium ammonium phosphate) and calcium oxalate, can remain in solution under conditions of supersaturation.
Their urine however does tend to form crystals from these dissolved salts. When these fine crystals clump together, uroliths form.
They are identified based on their mineral composition: struvite and calcium oxalate are the two most common feline uroliths.
Uroliths are mostly found within the urinary bladder or the urethra (the passage from the bladder to outside the body), but may also be located within the kidneys and ureters (the passageways from each kidney to the bladder).
Many animals do not display any symptoms. However, some cases will have difficulty in passing urine and have more frequent urination.
Blood is often seen within the urine, and affected cats can be vocal, unsettled and have an increased thirst.
These uroliths can potentially irritate the bladder wall and potentially cause an obstruction.
Male cats are at a greater risk due to their narrower urethra and a cat who cannot urinate requires immediate veterinary attention.
The median age for struvite urolithiasis is around seven. It is more common in female animals than in males.
Older male cats (8-12 years) are most affected by calcium oxalate uroliths.
Dissolving and prevention of these uroliths can be much more difficult and recurrence of calcium oxalate uroliths in cats is a potential and concerning problem.
Ultrasound scans and X-rays can be used to determine the size, shape and location of any stones for treatment options, and other underlying medical conditions. For example, kidney disease and diabetes can also be checked for.
Some forms of uroliths can be dissolved or flushed out, while others may have to be removed surgically.
Urinary support supplements and antibiotics are also often prescribed to prevent infection.
If urolithiasis is diagnosed, sometimes, depending on the type of uroliths found, advised prescription diets and dietary management can be effective at adjusting the urine pH and dissolving and preventing some types of urolith formation.
If this is the case, all other cat treats and human food snacks should be avoided.
Using such a “dissolution” diet uroliths may take anywhere from two weeks to five months to completely dissolve.
Thankfully, Abby was found to have struvite urolithiasis, which responded well to an advised prescription dissolution diet regime.
– Alison Laurie-Chalmers is a senior consultant at Crown Vets in Inverness