by Jen Azofeifa, DVM

Urethral Obstruction: A Medical Emergency

It is a common assumption that if a cat is straining in the litter box, he is constipated. However, primarily in male cats, a more concerning and life-threatening reason for straining in the litter box is a urethral obstruction.

What is a urethral obstruction? A urethral obstruction is when a cat is unable to urinate. This could be due to a physical obstruction by a plug of urinary crystals, bladder stones, mucus, a stricture, or neoplasia (cancer). It could also be secondary to edema (swelling) of the urethra or urethral spasms.

What are the signs of a urethral obstruction? Cats with a urethral obstruction visit the litter box frequently and posture to urinate but don’t produce urine, or produce only droplets which frequently contain blood. Some cats posture to urinate all around the house. They are often painful in the abdomen. The longer they remain obstructed, the more systemically ill they become. They can vomit while straining to urinate; become lethargic; lose their appetite; and in severe cases, they may collapse. It affects their kidneys (kidney failure is possible) and heart function, and can cause necrosis of the urinary bladder. They will often vocalize due to the extreme pain.

What do I do if my cat is straining? If you are not sure if your cat is straining to urinate or defecate, have him evaluated by your veterinarian immediately. If your veterinarian is closed, call the nearest emergency clinic. Do NOT wait! It is life-threatening and extremely painful to your cat.

Earlier signs that your cat is in danger of becoming obstructed include: visiting the litter box frequently, producing only small amounts of urine, blood in the urine, and signs that the cat is in pain.

If it happens once, can it happen again? Cats who have urethral obstructions often suffer from Feline Lower Urinary Tract Disease (FLUTD). Urethral obstruction is reported in 28.6-58% of all cats with lower urinary tract disease. (1) Some cats may obstruct once and never again; other cats are treated for a urethral obstruction and one month later it can happen again. Changes in diet, medical management, and decreases in the stress level can help prevent an obstruction, but nothing is 100% guaranteed. For cats with recurrent obstruction, a Perineal Urethrostomy can be performed to enlarge the urethral opening and help prevent frequent obstructions despite lower urinary tract disease.

What is the treatment? If you identify the disease early in the process, it could potentially be managed at home with oral medications and sometimes a diet change. Obstructed cats often need to have a urinary catheter placed and need to be hospitalized. The longer you wait, the more life-threatening the disease becomes, and the more costly it can be to treat it.

This is an extremely painful and potentially fatal condition. Early detection of signs of urethral obstruction can help save your cat’s life. Don’t wait to see your veterinarian.


1. Ruda L, Heiene R: Short- and long-term outcome after perineal urethrostomy in 86 cats with feline lower urinary tract disease. J Small Anim Pract 2012 Vol 53 (12) pp. 693-98.

Recent Posts

About Us

Ann Arbor Animal Hospital is a locally-owned animal hospital operating for over 90 years in Ann Arbor, MI.