Urethral obstruction (cat blockage)
A blockage of the urethra preventing urination, most common in male cats. Life-threatening within 24 hours — true emergency.
Urethral obstruction is one of the most urgent emergencies in feline practice. A mucous plug, stone, or inflammation blocks urine flow. Within 24 hours the bladder ruptures or the cat dies of kidney failure and electrolyte imbalance.
Male cats are at much higher risk than females due to their narrow urethra. Predisposing factors: overweight, indoor lifestyle, stress, dry-food-only diet, dehydration, prior episodes of FLUTD.
Signs: straining in the tray with no urine produced (or tiny drops with blood), vocalising in the tray, restlessness, hiding, vomiting, lethargy. By the time the cat is flat and unresponsive, the situation is critical.
Treatment: emergency vet visit, sedation/anaesthesia, urinary catheter to relieve the obstruction, IV fluids, electrolyte correction (potassium is the killer), pain management, hospitalisation for several days. Some cats need a perineal urethrostomy (PU surgery) if they reobstruct repeatedly — this widens the urethra surgically.
Prevention: wet food, multiple water sources, weight management, stress reduction, plenty of clean trays in separate locations. Routine annual exam.
If you have a male cat and notice straining in the tray, do not wait for morning. This is the single most time-critical emergency owners regret being late to.