Ureterolithiasis in Cats
Dr. Bari Spielman
Ureterolithiasis is the formation of a stone within a ureter, which is the tiny tubular structure through which the urine passes from the kidney to the bladder. This conditon affects both dogs and cats. Age, sex or breed predilection often depends on the stone type. Underlying urinary tract infections
Previous treatment of kidney stones, or nephroliths, by lithotripsy – which uses shocks waves to dissolve the stones – medical dissolution or surgery are predisposing factors.
There are several types of stones that affect cats and dogs. Each type of stone is often associated with it's own specific cause. General causes include:
Dietary factors or supplements
Administration of certain medications
Concurrent or underlying conditions or illness
Any previous cause of ureteral obstruction including narrowing, cancer or scarring
What to Watch For
Some patients are have no clinical signs
Abdominal or back pain
Straining to urinate
In cases of associated infection or kidney failure, watch for systemic signs of illness including:
Baseline tests to include a complete blood count (CBC), biochemical profile and urinalysis are recommended in all patients. Although results are often within normal limits, there may be changes consistent with kidney failure, urinary tract infection or other metabolic disorders.
A bacterial urine culture should be obtained, as there may be associated infection.
Abdominal X-rays should be obtained, as many stones are visible on X-rays, although normal X-rays do not rule out their presence.
Abdominal ultrasound evaluate the urinary tract, and may reveal associated hydronephrosis, which is the distension of the inside of the kidney with urine as a result of blockage of the ureter.
Excretory urography, a dye study of the upper urinary tract including the kidneys and ureters, may be of benefit in selected cases to help determine the presence and location of blockage.
Analyze all retrieved stones for stone type to aid in appropriate treatment strategies.
It is most important to determine whether the patient's condition warrants admission to the hospital for treatment, or treatment at home as an outpatient. Depending on the patient, recommended treatment options may vary.
Fluid therapy is indicated in those patients who are dehydrated, have severe infections or have concurrent kidney failure.
Inactive stones may only require periodic monitoring.
Medical and/or dietary dissolution may be attempted. It is important for both you and your veterinarian to monitor your pet very closely during this period, as it is possible that not all stones will dissolve, and they may get worse.
If your pet is in kidney failure or is having severe clinical signs associated with the presence of the stones, their removal, either surgical or by lithotripsy, is recommended.
Antibiotic therapy is indicated in those patients with concurrent urinary tract infections.
Home Care and Prevention
Administer all medication and diet as directed by your veterinarian and return for follow-up as recommended. If any change is noted in your pet's condition, notify your veterinarian. Promptly treat any factor that could predispose your pet to calculi or urinary tract infections. Dietary manipulation may be of benefit in helping to prevent the formation of certain stones.