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Megacolon in Cats

Constipation is the inability to defecate normally, resulting in retention of feces and/or hard, dry feces.

What to Watch For

You will need to differentiate straining to defecate (tenesmus) from straining to urinate and diarrhea-associated straining. Clear indicators of tenesmus include:

• Hard, dry feces, possibly with some blood or mucus on the surface
• Frequent attempts at defecation with little or no production of feces

Although constipation can affect any cat at any age, it is seen more frequently in middle-aged male cats. If constipation is prolonged, additional signs like lethargy, loss of appetite or vomiting may be seen.

Primary Cause

The most common causes of constipation are dehydration and megacolon. Megacolon is essentially a gradual loss of muscle tone in the colon, which makes it difficult to expel fecal material.

Immediate Care

If your cat is still producing some feces on a daily basis:

1. Make sure your cat has easy access to plenty of water and that he is drinking it.
2. Feed him a canned diet.
3. Try adding a tablespoon of canned pumpkin to the canned food.
4. If he still refuses to eat, another alternative would be to use a powdered, flavorless psyllium-based laxative (like Metamucil®). Start by adding 1/8 to 1/4 teaspoon of the laxative once a day to his diet.
5. Adjust the amount of the pumpkin or psyllium additives as needed until the stool has a more normal consistency.

If, however, it has been more than 48 hours since your cat has defected, in spite of your effort, the cat needs to be evaluated by your veterinarian.

Veterinary Care

Diagnosis

A physical exam and discussion of your cat's symptoms will help your veterinarian decide what additional tests are needed. Usually X-rays are taken; other tests like abdominal ultrasound, blood and urine tests may be necessary if it is thought the constipation is due to dehydration.

Treatment

If dietary adjustments (i.e., more fiber and water consumption) have not worked, your veterinarian will likely give your cat an enema. DO NOT use over-the-counter enema solutions designed for humans. Some of them contain enough potassium to kill a cat. Your vet will most likely give your cat fluids as well, either under the skin (subcutaneously) or intravenously. In some cases of megacolon, the cat must be sedated and the fecal material manually removed.

Other Causes

1. Litterbox avoidance (the cat doesn’t like the litterbox and therefore doesn’t defecate)
2. Fractured pelvis, which narrows the pelvic canal through which the feces must pass
3. Hair mats that block the anus
4. Inflammation of the colon
5. Foreign objects in the intestines

Prevention

Constipation can be prevented in many cases by providing adequate fiber and water to keep the cat “regular.” Some cats need prescription laxatives, usually containing lactulose, to stay “regular.”

Megacolon, on the other hand, is not yet well understood. In fact, there is no current way to prevent its development. Cats with megacolon may reach a point where nothing helps and euthanasia must be considered.