Paraphimosis, Urinary Blocks and Other Plumbing Crises

Urogenital emergencies share a common thread: tissue trapped, swollen or obstructed can rapidly lose blood supply or back pressure builds to a life-threatening degree within hours. Urinary blockage in male cats and paraphimosis in dogs are the two most frequently seen presentations, and both are true emergencies rather than conditions to monitor overnight.

Paraphimosis: When the Penis Cannot Retract

Paraphimosis occurs when the penis, once extruded, cannot retract back into the prepuce because of swelling, hair entrapment or a constricting ring of tissue, and the exposed mucosa rapidly dries and swells further, creating a worsening cycle that can lead to tissue necrosis if not corrected within hours.

Feline urethral obstruction, most common in young to middle-aged male cats, occurs when crystals, mucus plugs or inflammatory debris block the narrow, curved penile urethra. As urine backs up, bladder pressure rises, kidneys cannot excrete potassium, and the resulting hyperkalaemia directly interferes with normal cardiac electrical conduction, risking fatal arrhythmia within 24 to 48 hours.

Feline Urethral Obstruction and the Danger of Potassium

• Visible, swollen penile tissue that will not retract into the sheath (paraphimosis)
• Straining in the litter tray with little or no urine produced (blocked cat)
• Frequent trips to the litter tray with crying or vocalising
• A firm, painful, distended bladder palpable through the abdominal wall
• Lethargy, vomiting or collapse as toxin and potassium levels rise

A blocked cat straining in the litter tray is easily mistaken by owners for constipation, but the absence of urine production alongside frequent straining is the key distinguishing feature that should prompt immediate veterinary attention.

Why Male Cats Are Anatomically Vulnerable

Paraphimosis is diagnosed on direct visual examination, assessing the degree of swelling, tissue colour and viability of the exposed penis. Feline urethral obstruction is confirmed by finding a large, firm, non-expressible bladder on palpation, supported by blood work showing elevated potassium, urea and creatinine.

An ECG is used in blocked cats to check for the characteristic changes of hyperkalaemia, including tall, tented T-waves and a widened QRS complex, which guide how urgently potassium-lowering treatment must begin before anaesthesia for catheterisation.

Emergency Decompression and Catheterisation

Both conditions require prompt mechanical correction, and in blocked cats, stabilising dangerous potassium levels takes priority over catheterisation itself.

• Lubrication, cleaning and gentle reduction of the penis for mild paraphimosis
• Emergency purse-string suture or surgery for severe or recurrent paraphimosis
• Calcium gluconate and insulin-dextrose to protect the heart from hyperkalaemia
• Urinary catheterisation and bladder decompression under sedation for blocked cats

Preventing Recurrent Blockage

Cats successfully unblocked and catheterised typically stay hospitalised for 24 to 48 hours for fluid diuresis and monitoring, after which most return home eating and urinating normally. Recurrent blockage is common enough that some cats eventually need a perineal urethrostomy, a surgery that widens the urethral opening permanently.

Dogs treated for paraphimosis need the area kept clean and protected from self-trauma during healing, and any underlying cause such as hair entrapment or a preputial mass should be addressed to prevent recurrence.

When to seek help urgently

• A male cat straining in the litter tray with little or no urine produced
• Exposed penile tissue that will not retract, especially if swollen or discoloured
• A firm, painful, distended abdomen in any straining cat
• Vomiting, lethargy or collapse alongside straining to urinate

Both urinary obstruction and paraphimosis can become life-threatening within a day if untreated, so contact your veterinarian immediately rather than waiting overnight to see whether the animal resolves the problem on its own.