Urinary blockage, or urethral obstruction as it is officially known, is a common emergency that see over the course of a weekend... I literally had another 3 cats being treated for this once again on Saturday and Sunday. Three little kitties with three little catheters...
What is it?
Urinary blockage is almost exclusively a problem reserved for male cats, and occurs when the urethra becomes obstructed. The urethra is the “tube” that drains urine from the bladder out of the penis, and in males, it is very long and narrow. I usually describe to owners the difference between male and female urethras by using the example of McDonald’s straws… the female urethra is like a milkshake straw, while the male urethra is like a coffee stirrer. It gives the mental visual of just how much smaller of an opening male cats have, predisposing them to obstruction.
Obstructions are often the result of plugs of inflammatory material (such as white blood cells and mucus), as well as crystals or small bladder stones. All of this bladder “schmutz” conglomerates into a plug, lodges itself into the urethra, and blocks the exit for urine. When the urethra is completely blocked, and the cat has filled his bladder to capacity, his kidneys stop making urine as there is nowhere for it to go. With kidney “shut down” the body is no longer able to remove toxins from the blood or maintain a proper balance of fluids and electrolytes in the body, resulting in kidney failure and eventually death.
What are the clinical signs that an obstruction is occurring?
Most affected cats are 1 to 10 years of age. Initially cats may show signs of urinary tract inflammation, such as straining to urinate, frequent urination, blood in the urine, painful urination, or inappropriate urination (urinating somewhere other than the litter box). Once the cat becomes obstructed (“blocked”), they may attempt to urinate in the litter box but will produce only drops of urine or no urine at all. They may cry, move restlessly, or hide because of discomfort. Eventually they will lose their appetites, generally begin to vomit, and become lethargic. Complete obstruction can cause kidney failure in as little as 24 hours, and potentially death in as little as 48 hours. This is an easy diagnosis for your veterinarian to make because a cat with a urethral obstruction will have a very large, firm, and painful bladder that is easily felt in the back half of the belly on physical exam.
What tests are indicated?
Blood work is evaluated to check kidney function and to determine if there is any evidence of other systemic imbalances. The urinary toxins that build up can commonly cause life-threatening heart rhythm disturbances and an ECG may be needed. A urine sample is evaluated for crystals and may be sent in for culture. Radiographs of the belly are taken to see if calculi (stones) or other material are present in the kidneys or bladder.
What is the treatment?
Cats that have urinary obstruction require immediate emergency treatment and stabilization. Your veterinarian will need to anesthetize your cat to allow for placement of a urinary catheter into the urethra to flush out the plug or force the stone into the bladder. The bladder is then flushed through the catheter to remove as much urine sediment (“schmutz”) as possible. The urinary catheter is sewn in, with a urine collection system attached, and generally left in place for 48 hours to allow for inflammation in the urethra to settle down. After 48 hours, it is then removed, and the cat is monitored for an additional 24 hours to make sure that he doesn’t “re-block,” which is possible. During this 72-hour time frame, your kitty is placed on intravenous fluids so that it will urinate frequently, essentially helping to “flush out” the bladder and "clear the toxins." Medications to address pain, urethral spasms, and possible infection are generally used.
Once urine flow returns, the kidneys quickly begin to correct the metabolic disasters that have been taking place ("Ahhhhhh"). Often an extremely sick blocked cat can be snatched literally from the jaws of death by having proper fluid support and by re-establishing urine production. It is amazing how efficient the working kidneys can be in restoring the body’s balance!
Once the cat is no longer obstructed, management is the same as for any other cat with feline idiopathic cystitis that is not obstructed.
What is the prognosis?
Prognosis for recovery is often excellent if treated appropriately and in time. If sudden kidney failure does develop as a result of the obstruction, it is generally reversible and will get “back in check” with IV fluid therapy support. The biggest concern, however, is the potential to re-obstruct. For cats that have 2 or 3 recurrences of obstruction, your veterinarian will recommend a surgical correction of the problem with a PU (perineal urethrostomy) surgery. This procedure can be likened to a “sex change” in your male cat, and it involves the surgical widening of the urethra to make it more the size of a female urethra.
It is crucial to realize that the cat is at risk for re-blocking for a good week or two from the time of discharge. This is because the irritation syndrome that led to blocking in the first place is still continuing, and as long as the episode continues, blocking is a possibility.
Urethral obstruction is a true medical emergency, and any cat suspected of suffering from this condition needs to receive immediate veterinary evaluation and care.
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