Male cats are more prone to urinary blockage because their urethra gets very narrow as it passes through the penis. Obstructions may be caused by mucous plugs of inflammatory material or small crystals or stones passing from the bladder through the urethra.
signs of urinary obstruction
- straining to urinate
- frequent urination
- blood in urine
- firm, distended bladder (palpable through abdominal wall)
- crying in pain
- constant licking of genitalia
- loss of appetite
- vomiting
- depression (as toxins build up)

For urinary obstruction, the vet may place a catheter into the urethra to flush out the plug or sediment. For stones in the bladder or lodged in the bladder neck or urethra, cystotomy is performed. If the obstruction is not relieved, urine builds up & the bladder may rupture. It can also lead to irreversible kidney damage & eventual death.
Cats that experience recurring or severe episodes of urethral obstruction may require a surgical procedure called Perineal Urethrostomy (PU).

Preparing the patient for surgery. The distal part of the penis will be removed & the urethra widened to prevent recurrent urinary obstruction.

The penis is carefully freed of its attachments & dissected from the surrounding tissue. The edges of the urethra is sutured to the surrounding skin to create a wider urethral opening.

An Elizabethan collar prevents the cat from licking the surgical site until the sutures are removed.
Perineal urethrostomy does not prevent urinary tract inflammation or stone formation. However, the wider urethral opening (like the female anatomy) provides a wider passageway for plugs, crystals or small stones to be passed out. The likelihood of future obstruction will be decreased.