Pseudomembranous cystitis, an unusual condition associated with feline urine outflow obstruction: Four cases.

The clinical follow-up of four cats presumptively diagnosed with pseudomembranous cystitis is described. All presented with acute urine outflow obstruction and acute renal failure. Urethral catheterisation was performed without difficulty but ultrasonography and contrast radiography consistently revealed abnormal bladder wall and content. One cat was euthanased, the remaining three underwent an exploratory cystotomy. Abundant inflammatory and necrotic tissue covering an ulcerated bladder mucosa was removed. All cats recovered uneventfully. No definitive cause was identified but the clinical course of the disease was not typical of idiopathic cystitis.