What is Urolithiasis?

All animals, man included, are subject to their developing stones within their urinary tract. When stones form, the condition is known as urolithiasis and the stones are called uroliths. These stones may form anywhere within the urinary tract: kidneys, ureters, bladder, and urethra. If the stones are small enough to be passed out in the urine, there may be no evidence of their presence other than discomfort and seeing the stones themselves. If the stones are too large to pass, then a serious problem will ensue.

The formation of stones may be due to one cause or in combination with several other causes. The most common causes of urolithiasis are listed below.

1. Urinary Tract Infection (UTI):
bacterial infections may alter the ph of the urine to cause crystals to precipitate out from the waste-mineral-laden urine. These crystals then may form aggregates to become stones.

2. Metabolic disorders:
hereditary disorders (as in Dalmatians with urate stones), birth defects (as in dogs and cats with portal vascular abnormalities), and acquired metabolic disorders (hyperparathyroidism).

3. Dietary Factors:
high-magnesium alkalizing diets (high ash) in cats, diet with excessive amounts of corn gluten or soybean hulls, over supplementation with calcium/phosporus, and in ferrets the feeding of dog food and/or low quality cat food.

4. Idiopathic (unknown) causes:
The clinical signs and symptoms are variable and are multifactoria.

A. The size, number, and location of the stones within the urinary tract will determine the severity of the condition.

B. If there is a partial or complete obstruction of urine flow, then the potential for uremic poisoning is greater. Uremic poisoning occurs as the elimination of the toxic waste products is pervented allowing their absorption into the general circulation thereby producing nausea, vomitting, dehydration, urine-breath, in appetence, depression, coma and/or seizures, then death.

C. The presence of UTI is common and complicates the condition. Foul smelling urine is detected if UTI is present.

D. Bloody urine occurs as the bladder wall becomes traumatized from the friction produced by the stonesas they rub off the bladder's lining.

E. Pain or discomfort occurs as the stones travel from the site of their formation to eventually be passed if possible and there is straining to urinate. Cats will stay in the litter box without producing any urine. Dribbling of bloody urine is common.

Should your pet exhibit any of these signs and symptoms, you have an animal that may be in danger of becoming very ill and eventually dying a painful death. The earlier that this condition is diagnosed and the sooner the theraphy is instituted, the faster your pet may be returned to normal. In some cases the treatment may involve surgery. Antibiotics and medications may need to be administered long term or for life. More than likely your veterinarian will suggest a change in diet. This is a condition not to be ignored. It will not rectify itself.

Dr. John N. Case, Jr. is the owner of the Clinic for Animals. 5201 N. State Road, Tamarac, Florida. Phone: (954) 739-4500. Dr. Case has a small animal practice.