What Causes Blockage in Cats?

You don't realize the joy of peeing until you can't do it.
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Uh-oh. Kitty wasn't able to pee and you rushed him to the vet. While the vet got him unblocked, you want to make sure it doesn't happen again so neither one of you ever repeat that nightmare. If the vet diagnoses the cause, there are ways to help prevent recurrence.

Urethral Blockage

Normally, urine flows from the bladder through the tube-like urethra for elimination. If something blocks or obstructs the urethra, it's not just uncomfortable, but life-threatening. Because the male cat's urethra is smaller and narrower than females, they're much more likely to experience blockages.


Signs of urinary obstruction in cats are pretty much the same as for any sort of feline lower urinary tract disease. If Kitty starts climbing in and out of the litter box, straining to pee, take him to the vet immediately. He might cry out in pain as he tries to urinate. He'll also lick his genitals, trying to obtain comfort. As the blockage continues, the urine backs into his kidneys. If Kitty doesn't get to the vet as soon as possible, he could be dead within three or four days from toxin accumulation.


Most blockages result from urinary stones that pass from the kidneys into the urethra, or from plugs made of mucus, bladder crystals or stones stuck together. The causes of these stones or plugs vary, from an all dry food diet, bacteria or viruses, to stress. A hereditary component is also a possibility, as Persian cats are more likely to experience obstructions than other breeds.


After your vet examines Kitty, she'll sedate him and place a catheter into his urethra. Then she flushes out the blockage, whether it's a plug or stone. Kitty then receives intravenous fluids to make sure he pees a lot. Sometimes catheterizing isn't enough to unblock Kitty, especially if he's got large stones. If that's the case, surgery, called a cystotomy, is required. If Kitty is repeatedly blocked, your vet might perform a surgery known as perineal urethrostomy. This procedure removes most of Kitty's penis, but creates a very wide opening so blockage is unlikely to recur.


To prevent future blockage, your vet will recommend dietary changes. She might prescribe a special diet, depending on the type of crystal or stone found in his bladder or urine. Low magnesium foods keep Kitty's urine acidic, to prevent formation of struvite crystals. If calcium oxalate stones were the culprit in Kitty's blockage, your vet will prescribe a food that keeps his urine more alkaline for stone prevention. Always make sure Kitty has plenty of fresh, clean water available. Keep his litter box as clean as possible. If you have a multiple cat household, try to provide a litter box for each feline. If that's not possible because of space limitations, put out as many boxes as you can.

Hairball Blockage

Feline blockages also occur in the intestines because of hairballs. You're familiar with hairballs -- those lovely clumps of matted hair and stomach juices that Kitty hacks up on your carpet. Normally, after Kitty grooms himself that hair goes through his intestines and is excreted in his feces, but sometimes he'll cough it up. The problem starts when a mass of hair can't go through his intestines. He'll be constipated, so you'll notice him going in and out of the litter box, but you'll find sufficient amounts of urine so you know it's not a urinary blockage. Usually the hairball passes after your vet administers a laxative to Kitty. Don't try this at home -- it's important for a cat with an obstruction to receive veterinary attention. If the laxative and intravenous fluids don't work, surgery might be necessary.

Hairball Prevention

Groom Kitty regularly so hair goes onto the brush rather than into the cat. Wet food provides moisture for the intestines rather than a strictly dry food diet. Give him hairball preventives. These are tasty commercial preparations you can offer to Kitty as a treat or smear on his paws for him to lick off. Put some canned pumpkin in his food to add fiber.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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