LOWER URINARY TRACT DISEASE IN CATS
Symptoms: Typical signs of urinary problems in cats include urination out of the litter box, vocalizing or straining during urination, frequent attempts to urinate with small spots or no urine produced, and blood in the urine.
Male cats may become obstructed if the narrow urethra is plugged with blood, mucus, or crystals. This is a life-threatening emergency-A male cat straining and not producing urine, or weak, lethargic, painful, or vomiting, must be evaluated immediately!
Causes: Bladder stones and infections are readily identifiable causes of urinary tract disease, but account for less than 10% of cases. Diets high in magnesium and phosphorus, low in moisture, and that produce high urine pH predispose some cats to form struvite crystals or stones; diets high in calcium, vitamins C and D, low in phosphorus, and producing low-pH urine may predispose to oxalate crystals or stones. Mucus production secondary to viral diseases or stress may be a factor. Occasionally tumors are responsible. However, most cases are of unknown cause. These are called "idiopathic cystitis."
Diagnosis: A urinalysis is done to identify risk factors for stones (crystals, high or low pH) or infection. Many cases have only blood in the urine, with no other abnormalities. An X-ray or ultrasound is done to identify bladder stones; tumors can be seen with ultrasound or x-rays done with air or dye in the bladder.
Treatment: Bladder stones are generally removed surgically. Infections are treated with antibiotics.
Many idiopathic cases will resolve in days to weeks with or without treatment. Due to increased risk of infection secondary to bloody urine, antibiotics are often prescribed as trial therapy. Even though many cases resolve spontaneously, the cat is still uncomfortable until resolution occurs. Pain medications are indicated in most cases.
Chronic (longer than 3 weeks) or recurrent cases in which infection and stones have been ruled out may benefit from amitriptyline, possibly due to anti-histamine effects or reduction in stress hormones. The benefit of amitriptyline has not been shown in controlled scientific studies. If amitriptyline is prescribed, it is usually used for 2 months, then gradually discontinued if no more episodes occur.
Some cats benefit from a diet that is specifically designed to prevent crystals, if they were identified on urinalysis. If no crystals were seen, a diet producing neutral pH and high in moisture (canned food) while avoiding the risk factors for struvite and oxalate stones can be used.