Male cats are prone to developing a urinary blockage or obstruction, and when this condition occurs these cats are commonly referred to as "blocked toms." This is considered an emergency, as the cat is unable to void any urine.
Why are male cats predisposed to developing a urinary blockage?
Male cats can become more easily blocked because of the anatomy of their urinary system. The urethra is a tubular structure that leads from the bladder to the outside of the body. In the female cat, the urethra is shorter and larger in diameter. In the male cat, the urethra, especially the portion that is within the penis, is quite narrow. It therefore can become more easily blocked.
What blocks the urethra?
The urethra may be blocked by a urinary stone, an accumulation of microscopic crystals and mucus that forms a "plug", blood clots, or a tumor. Sometimes the urinary blockage is not mechanical, but is either due to muscle spasms along the urethra, or a nerve problem that causes the cat to be unable to urinate. Regardless of the cause, the urine is not able to exit the bladder, and starts to build up in the bladder.
What symptoms will a blocked cat have?
A cat with a urinary blockage will:
- Strain, but produce no urine
- Often vocalize (howl or meow) while trying to urinate
- Lick his genital area
- Often have blood in any urine that is produced
If the cat remains blocked, he will become seriously ill and show:
- Loss of appetite
Toxins will start to accumulate in the blood within 24 hours of a cat becoming blocked. If the urinary obstruction continues, death can result in a matter of a few days.
How is urinary blockage diagnosed?
The veterinarian will palpate the urinary bladder and find that it is very full. This and the history that the cat has been unable to urinate generally provides enough information for the diagnosis of a urinary obstruction. Further testing may be necessary to determine the exact cause. Radiographs are commonly taken to determine if one or more urinary stones is causing the blockage. A complete blood count and chemistry panel will be performed to assess the cat's overall health and to determine if toxins or potassium have built up in the cat's blood stream due to the urinary obstruction.
How is a blocked cat treated?
Under anesthesia, the veterinarian will attempt to place a urinary catheter in the cat. If that is not possible, some of the urine can be removed from the bladder through cystocentesis. A urinalysis and culture and sensitivity will usually be performed on the urine that is collected. Usually a intravenous (IV) catheter will be placed and the cat will be given fluids, along with pain relievers and antispasmodics (medications to decrease the muscle spasms in the urethra). If the potassium levels are high, additional medications may be given to lower the level. If the bladder has been enlarged for a long time, it may not be able to contract and express the urine until the damge has healed. Medications may need to be given to help the bladder contract. A special diet may be recommended depending upon what caused the blockage.
If a urinary catheter cannot be passed and the blockage relieved, or if the cat has recurring bouts of urinary obstruction, surgery may be necessary. The surgery essentially removes the penis of the cat. The wider urethra closer to the bladder is sutured to the skin between the anus and the scrotum. This creates a new permanent opening through which the urine can pass. This procedure is called a 'perineal urethrostomy.'
What is the prognosis for a blocked cat?
The prognosis for a cat with urinary blockage depends largely on how long the obstruction was present and if it was possible to remove it. The longer the obstruction is present, the more critically ill the cat becomes, and the poorer the outcome. A cat who was blocked once may be predisposed to becoming blocked again. In almost all cases, cats who have had a perineal urethrostomy will not become blacked again. Rarely, complications of the surgery may occur including urinary tract infections or a stricture that would require further surgery.