Ureterolithiasis in Cats
Ureterolithiasis is a condition which involves formation of stones that may lodge into the ureter, causing its blockage. A muscular tube which connects the kidney to the bladder, the ureter also carries urine from kidneys to the bladder. Typically, ureter stones originate in the kidneys and later pass down into the ureter.
Depending on the size and shape of the stone, the stone may pass down to the bladder without any resistance or it may partially or completely obstruct the ureter, resulting in the dilatation of the upper portion of the ureter and subsequent kidney damage.
There are a number of different types of stones found in animals and type of stone may vary in according to breeds, age, and sex of the cat.
Symptoms and Types
Some cats with ureterolithiasis display no symptoms, especially during the initial stages. Otherwise, be attentive to the following symptoms:
- Kidney failure
- Enlargement or shrinkage of the kidney
- Accumulation of waste products like urea
- Rupture of ureter, resulting in urine accumulation in the abdomen
The underlying cause may vary depending on the type of the stone. Typical causes include:
- Genetic factors
- Urinary tract infections
- Adverse drug reaction
- Diet and/or supplements
- Surgery that has lead to the narrowing or scarring of the ureter
Your veterinarian will conduct a complete medical history and perform a physical examination on your cat. He or she will then use routine laboratory tests including complete blood count, biochemistry profile, electrolyte panel, and urinalysis to assess the condition of your cat and severity of the disease. These tests also help in evaluating your pet for any other concurrent disease or condition.
Abdominal X-rays are extremely useful in visualizing the stones and their size; it will also confirm if the kidney has become enlarged as a result of the stones. Similarly, X-rays will depict if the ureter is intact or ruptured. In some cases, a special dye is injected intravenously and X-rays are taken afterward. This helps better visualize the stones by providing contrast. Ultrasound scans is another method for detecting ureter stones and kidney size.
Removing the obstructing stones is the primary objective of treatment. Fortunately, advances in modern technology has enabled veterinarians to remove the stones without surgery. A new technique called extracorporeal shock wave lithotripsy removes stones located in kidney, ureter, or bladder by producing shockwaves that break apart the stones, which can then be passed through the urine. Extracorporeal shock wave lithotripsy technique does not work for all animals, so consult with your veterinarian if it is right for your cat.
For cats in which surgery is necessary, intravenous fluids are administered to maintain them hydrated. Antibiotics are also prescribed for cats with concurrent urinary tract infection.
Living and Management
As relapses are common, continuous monitoring of the cat's condition is necessary. Typically, followup evaluations are done every 3-6 months. Depending on the type of stone, your veterinarian will suggest dietary changes to prevent future episodes of stone formation. If your cat is not tolerating the dietary changes well, contact him or her for necessary changes.
The overall prognosis is highly variable depending on the type of the stones.