Your 5-year-old male neutered domestic shorthair, Oliver, has been visiting the litter box repeatedly. He's straining, crying, and producing nothing—or only a few drops. He's less interested in food. When you gently palpate his abdomen, you feel a firm, grapefruit-sized mass. It's been about 24 hours since you last saw him pass a normal amount of urine.
Warning: Feline urethral obstruction is the #1 cause of sudden death in male cats with urinary signs. Obstruction can be fatal within 24-48 hours. Seek emergency veterinary care immediately. Do not wait.
Feline urethral obstruction occurs when crystals, stones, or inflammatory plugs block the narrow male urethra. Urine cannot exit the bladder. The bladder distends. Potassium and other waste products accumulate. Without treatment, the cat develops acute kidney injury, severe hyperkalemia, and cardiac arrest—often within 24-48 hours.
The Triage/Emergency Specialist immediately flags this as a life-threatening emergency. When you describe straining with no urine production and a distended bladder, the AI recommends: Seek emergency veterinary care immediately. Do not wait.
Obstructed cats often develop hyperkalemia (elevated potassium). Potassium affects cardiac conduction. Severe hyperkalemia causes bradycardia, arrhythmias, and eventually asystole. The Vital Signs Reference tool alerts you: a heart rate below 140 bpm in a stressed cat may indicate hyperkalemia. ECG may show spiked T-waves, widened QRS, or bradycardia. Treatment includes IV calcium gluconate (cardioprotective), insulin+dextrose, and sodium bicarbonate to shift potassium intracellularly—but the definitive treatment is deobstruction.
Under sedation or anesthesia, the veterinarian passes a urinary catheter through the urethra into the bladder, relieving the obstruction. The bladder is flushed to remove plugs and debris. The catheter may remain in place for 24-48 hours to allow urethral swelling to subside. IV fluids correct dehydration and support kidney function. Pain management and monitoring of electrolytes are essential.
After discharge, recurrence is common (up to 50% within 1-2 years). Prevention strategies include prescription urinary diets (to dissolve struvite or prevent crystal formation), increased water intake (canned food, fountains), stress reduction, and in recurrent cases, perineal urethrostomy (surgical widening of the urethra). The Bloodwork OCR can help you understand post-unblocking lab values—elevated creatinine and BUN typically improve over 24-72 hours with fluids.
When unsure about urgency, use the Triage/Emergency Specialist to help prioritize. The Vital Signs Reference alerts for bradycardia (potential hyperkalemia).
- Straining + no urine = emergency. Do not wait. Obstruction can be fatal within 24-48 hours.
- Male cats are at highest risk due to their narrow, long urethra.
- Bradycardia in an obstructed cat suggests hyperkalemia—a critical finding.
- Use PetMed AI Triage when you're unsure—it helps prioritize urgency.
- Recurrence prevention is key: diet, water, stress management.