Most affected cats are within 1 to 10 years of age. Signs and symptoms may vary from mild to severe. Initially cats may show signs of urinary tract inflammation and discomfort, including straining to urinate, frequent urination, blood in the urine, painful urination, and inappropriate urination (urinating outside of a litter box).
These bouts can resolve in 5–7 days but recur in many cats within 6–12 months. Symptoms are profound and life threatening if complete obstruction occurs and no urine can get out of the body. Once cats become completely obstructed, they may attempt to urinate in the litter box but will produce no urine. The cat may cry, move restlessly, or hide because of discomfort, and eventually lose their appetite and become lethargic. Complete obstruction can cause death of the cat in 3–6 days. A cat with a urethral obstruction will have a large, painful bladder that is easily felt in the back half of the belly unless the bladder has ruptured.
Some risk factors have been evaluated for lower urinary tract disease in cats. Increased risk was found in cats that eat dry food, being kept indoors, nervous/fearful/aggressive behaviors, stress, and being in multi-cat household. The incidence of urinary obstructions is reportedly higher in the winter months. Bladder inflammation leading to mucous plugs (sometimes called “Feline Urologic Syndrome” or “FUS”) is more common in male cats. Congenital outpouchings of the bladder (“vesicourachal diverticuli”) can increase the risk of bladder infection, but they may also be a result of chronic inflammation.