It is generally accepted that urethral calculi or mucous plugs are important in the pathogenesis of urethral obstruction; however, recent data have suggested an idiopathic cause of obstruction in greater than 50% of evaluated cats. The effectiveness of medication, intermittent cystocentesis, and low-stress environment was evaluated as an alternate to urethral catheterization and hospitalization in 15 obstructed male cats. Patients with abnormal physical examinations, severe metabolic derangements, or radiographic evidence of cystic or urethral calculi were excluded from the study. Patients were treated with subcutaneous fluids and doses of acepromazine, buprenorphine, and medetomidine to facilitate analgesia and sedation. Bladder cystocentesis was performed up to 3 times per day as necessary to relieve bladder distention. Cats were checked every 8 hours for spontaneous urination, and treatment was considered successful if urination occurred within 3 days. A total of 11 cats (73%) had a successful outcome, in comparison with a 91% to 94% success rate using traditional hospitalization/urethral catheterization techniques. Severe complications developed in 4 cats; 3 of these cats were euthanized. All cats with failed treatments generally had more severe bladder wall disease and higher serum creatinine values at presentation. There was a much lower rate of reobstruction within 72 hours of spontaneous urination in cats treated in this study versus previously reported postcatheter reobstruction rates (14%). This study supported the hypothesis that a significant proportion of the urethral obstructive process in male cats is due to spasm and edema rather than the physical presence of a urethral plug or calculi.

Commentary: This study may begin to redefine the way that we treat cats with urethral obstruction and profoundly decrease the number of cats with urethral obstruction that are euthanized due to financial constraints. It is exciting to know that there is a possibility of clinical success by using a minimalist technique. Without future research, it is inappropriate to offer this technique as a direct alternative to conventional management of obstructed cats.—Heather Troyer, DVM, Diplomate ABVP (Canine & Feline Practice)

A protocol for managing urethral obstruction in male cats without urethral catheterization. Cooper ES, Owens TJ, Chew DJ, Buffington CAT. JAVMA 237:1261-1266, 2010.