Urethral obstruction in cats

Possible signs

• Frequent trips to the litter tray, prolonged squatting or straining to urinate
• No urine or only a few drops; crying, repeated genital licking, blood in the urine or urinating outside the tray
• Restlessness or hiding, followed by refusal of food, vomiting, lethargy and weakness as the condition worsens
• A tense or firm, painful abdomen; the cat may react sharply when the abdomen is touched

What it is

The urethra carries urine from the bladder out of the body. When it is blocked, urine cannot pass, the kidneys cannot clear waste normally, and dangerous potassium and other electrolyte changes can rapidly affect the heart. Severe untreated obstruction can cause acute kidney injury, shock, and damage or rupture of the overstretched bladder, allowing urine to leak into the abdomen. Inflammatory plugs, spasm and stones are common causes. Obstruction occurs mainly in male cats because their urethra is longer and narrower, but suspicious signs in any cat need urgent assessment.

What to expect at the veterinarian

The clinic will triage the cat promptly and assess the bladder, temperature, circulation and heart rhythm. Blood tests commonly check kidney values and potassium; urinalysis, radiographs or ultrasound may be needed. After pain relief and stabilisation, the obstruction is usually relieved with a urinary catheter under sedation or anaesthesia. Some cats need several days in hospital until they can urinate on their own and a plan for the underlying cause is established.