Urethral obstruction is a common, life-threatening but treatable emergency in cats. In one study, 10% of all male cat cases that present to hospitals are there for this reason. This is an issue that you should be aware of if you have a male cat, because recognizing the signs early can make the difference between life and death for your cat. It is a problem that may occur at any time of the year, but for some reason, we tend to see more cases when the seasons change. Thus, I am talking about it now.
Male cats can easily develop obstruction of the urethra (the tube draining urine from the bladder out of the penis) because the urethra is so small. Obstructions are often the result of plugs of inflammatory material or small calculi or “stones” that have formed in the kidneys and have passed down into the bladder. The cause of the inflammatory materials and stone formation is not well understood, though viral infections and diet may play a role.
Signs and Symptoms
Most affected cats are within 1-10 years of age. Initially cats may show signs of urinary tract inflammation, including:
– straining to urinate
– frequent urination
– blood in the urine
– painful urination
– inappropriate urination (urinating somewhere other than the litter box)
These bouts usually resolve in 5-7 days but will recur in many cats within 6-12 months. Once the cats become obstructed, they may attempt to urinate in the litter box but will produce no urine. They may cry, move restlessly, or hide because of discomfort, and eventually will lose their appetites and become lethargic. Complete obstruction can cause death of the cat in 3-6 days. A cat with a urethral obstruction will have a large bladder that is often easily felt in the back half of the belly.
Cats that eat dry diets and therefore get less water or diets high in calcium, protein, or salt may be at an increased risk for developing calcium oxalate stones. Bladder inflammation leading to mucous plugs (sometimes called “Feline Urologic Syndrome” or “FUS”) is more common in m ale cats. Congenital out-pouchings of the bladder can increase the risk of bladder infection, but they may also be a result of chronic inflammation.
In cats with signs of urinary tract inflammation, blood work is evaluated to check kidney function, level of dehydration and electrolyte imbalances that might need to be addressed. Also, it is used to check for evidence of infection or other systemic illnesses. A urine sample is evaluated for crystals and may be sent in for culture, although bacterial infections of the bladder are uncommon in cats. In those cats prone to recurrent infections, x-rays of the abdomen may be taken to see if calculi (stones) or other material are present in the kidneys or bladder. Sometimes contrast material is used to further detect if there are bladder wall defects or strictures (narrowing) that have formed in the urethra.
Cats that have urinary obstruction require emergency treatment. Your veterinarian will sedate or anesthetize your cat and place a catheter into the urethra to flush out the pour or force the stone into the bladder. The bladder is thoroughly flushed through the catheter to remove any remaining sediment. The urinary catheter is then typically left in place for 2-3 days until urethral swelling subsides. Your veterinarian may also prescribe pain medication or other drugs to make your pet more comfortable and relaxed.
If stones have been flushed into the bladder, a cystotomy (surgical opening of the bladder) is performed to remove the stones. Sometimes, depending on the type of stone, diets can be used to attempt to dissolve the stone. There is risk involved in this approach, as there are no guarantees that the stone will shrink, and it may not shrink in time to not re-block the urethra. Other stones do not respond to diet, and are better removed surgically.
If an obstruction recurs, a thorough work-up (including x-rays and cultures of the urine) should be performed before surgery is considered. If your cat has three or more recurrences, cannot be managed medically, and does not have any underlying conditions that could cause recurrence your veterinarian may recommend a perineal urethrostomy (“PU”), or surgical widening of the urethra.
The most important thing is to recognize when and if your cat is spending more time in the litter box. Best to inform your veterinarian early in the process. Since the signs of urinary tract infection so closely mimic those of early urethral blockage, you should act quickly. Both processes will require medical treatment, and one is life threatening.