Bladder stones in dogs and cats
These are stones which vary in size from being microscopic sandy particles to large visible stones lodged somewhere along the urinary system in dogs and cats. These stones are formed as a result of minerals in urine that are clumped up together to form stones, also known as urinary calculi or bladder stones. The common cause for formation of these stones is contributed by the pH of the urine, which can be influenced by bacterial infection, diet and some type of medications. These stones can be anywhere between the kidneys, ureter, bladder and urethra.
Genetic plays a role, where in some dogs physiological processes produce substances that are precursors for stone formation more than in other dogs. Some breeds like the Dalmatians, English bulldogs and black Russian terriers are known to be genetically predisposed to the formation of urate crystals. This is due to decreased ability to oxidise uric acid to allantoin, which is excreted in the urine. Dalmatians also have a metabolic defect that is thought to result in an inability to reabsorb uric acid into the renal tubules for excretion.
Bacterial infections tend to make urine more alkaline and this enhances formation of some specific crystals known as struvite. These bacterial infections also produce an enzyme called urease which creates a cascade of reactions which will eventually form struvite crystals.
Feeding you pets with the wrong types of food especially those with high protein, magnesium and phosphates increase the chance of crystal formation in urine.
The symptoms of bladder stones vary from observing blood in the urine, constant licking of the genitals, inability to urinate, Straining to urinate, and/ or increased frequency of urination, tender or abdominal pain, vomiting and if unresolved, death is imminent.
Diagnosis involves physical examination after obtaining proper history of the pet from the owner, x-rays, urine analysis that will determine infection, type of the crystal and the urine pH.
Treatment involves medical management or surgery depending on the location and type of the stones. Some stones like the struvite and ammonium urate are some of the stones that can be dissolved by dietary management, which eventually they will resolve. Medical management is also through treatment of infections where struvite stones are involved. In addition, struvite stones can be managed with medications that alters the urine pH from alkalinity to acidity. Some stones like calcium oxalate will only be managed by physically removing them either through surgery or urohydro-propulsion.
Prevention of bladder stones involves increasing consumption of water by your pet by placing multiple bowls of water in the garden, and dietary changes through advise from your veterinary doctor, which will also depend on the type of bladder stone your pet is having. If your pet has regular bladders stones, it is important to have regular examinations by your vet to ensure that there are no recurrence.
References
Osborne, CA; Lulich, JP; Forrester, D; Albasan, H. Paradigm changes in the role of nutrition for the management of canine and feline urolithiasis. In Osborne, CA; Lulich, JP (eds.) Veterinary Clinics of North America Small Animal Practice: Changing Paradigms in Diagnosis and Treatment of Urolithiasis. W.B. Saunders Co. Philadelphia, PA; 2009 (January) 127-141
Sorenson, J.L and Ling, G.V (1993). Metabolic and genetic aspects of urate urolithiasis in Dalmatians.J Am Vet Med Assoc :203(6):857-62.
