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Nutrition Nuggets is the newest offshoot of petMD's Cat Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of cat nutrition.

Dietary Management of Megacolon in Cats

June 14, 2013 / (5) comments

Megacolon can be a frustrating disease for veterinarians, owners, and, most importantly, for the affected cats. The disease develops when the muscles within the wall of the colon (large intestine) no longer contract as they should. Feces builds up and dries out within the colon, resulting in constipation.

Most cases of megacolon are idiopathic, meaning we don’t know why the condition developed in that particular individual. Less frequently, an injury, developmental disorder, or other primary condition prevents the colon from emptying as it should, causing it to stretch and stop functioning normally. In either case, cats with megacolon typically:

  • Strain to defecate
  • Exhibit pain while defecating
  • Have abdominal discomfort
  • May lose their appetite
  • Produce small amounts of hard fecal matter that can contain blood or paradoxically produce small amounts of liquid feces, leading their owners to wrongly diagnose them with diarrhea

Definitively diagnosing megacolon is not too difficult. During a physical exam, a veterinarian can usually feel that the colon is distended with feces, a finding that is confirmed with abdominal X-rays. Additional diagnostic tests (e.g., blood work, urinalysis, and/or abdominal ultrasound) may be necessary to determine if megacolon has developed as a result of another condition.

The initial treatment for megacolon centers on getting the impacted feces out of the colon. In milder cases, an enema is all that is needed. (As an aside, never give a cat an enema at home without first consulting with a veterinarian. Some over the counter formulations are very toxic to cats.) More severely affected cats need to be put under general anesthesia and undergo a manual evacuation — fancy words for the veterinarian donning latex gloves and removing fecal material by hand, a procedure that necessitates lots of patience and lubrication.

Once the cat is all cleaned out, the focus turns to preventing future episodes of constipation. Since fecal matter consists primarily of unabsorbed food, it shouldn’t be too surprising that dietary manipulation is central to treatment. In my experience, most cats respond best to a highly digestible food that reduces the amount of feces they produce. They simply have less to expel, which decreases the risk they’ll get backed up. Cats are cats however, and some prefer to do things differently.

When constipation persists despite feeding a highly digestible food, a high-fiber diet is worth a try. These cats then produce more stool than normal, but it is softer, easier to pass, and the increased bulk seems to stimulate the colon to contract more effectively. A couple of teaspoons of psyllium, canned pumpkin, or wheat bran can be added to a cat’s regular food to increase the fiber content.

Whichever diet works best, it is very important for the cat to remain well-hydrated so stool in the colon stays soft. For this reason, I generally recommend canned food only for my megacolon patients. Intermittent subcutaneous fluid therapy can be helpful as well. Stool softeners (e.g., lactulose) and medications that enhance muscular contractions in the wall of the colon (e.g. cisapride) are also frequently prescribed.

Most cats respond well to dietary and medical management, although they may still need an enema from time to time. In advanced cases, surgically removing the non-functioning portion of a cat’s colon is a good option, which brings about the need for more dietary manipulation … but that’s a subject for another day.

Dr. Jennifer Coates

Image: Kristine Paulus / via Flickr

Comments  5

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  • Megacolon
    06/17/2013 10:16pm

    Can megacolon be caused by a kitty getting very, very constipated which would cause the intestinal walls to be stretched? Will cleaning the intestine out always (usually?) allow the intestinal walls to contract back to their intended size or are there cases where they are stretched so much that they don't contract back to where they should be?

  • 06/18/2013 01:01pm

    Yes, megacolon can be a secondary condition caused by prolonged/severe constipation. By the time megacolon is diagnosed, the changes are typically permanent.

  • 08/28/2013 09:55pm

    Hi, My cat, Lido, has a rear left leg amputation. We adopted him from the humane society so his history is spotty and we don't know why his leg was amputated. His issues include frequent constipation. My vet recommended checking/squeezing anal glands and adding coconut oil to his diet. I have done these things but he continues to have problems. It is even more painful for him because he can't properly squat down. He also has shaking where his stump is.

  • Chicken breast
    10/23/2013 06:03pm

    I have a 13 year old cat who has megacolon. I've tried everything to help alleviate his constipation over the years. Recently about 3 months ago I started giving him a bowl of chicken breast every day. I buy a bag of frozen precooked chunks and give him about 5 chunks a day. Since I started doing this he hasn't been constipated and pooing in the box 3 to 4 times a week. It's been a miracle for me so I thought I'd share this and maybe you can try this as chicken is great for them and it wouldn't hurt to try. I also want to mention he has been more active and playful since I've been giving him the chicken which I think is partly because he's not constipated anymore and also I think the chicken is good for them as they are not meant to eat cat food in nature. Hope this works for you.

  • 10/24/2013 03:28am

    Please make sure your cat is eating enough of a nutritionally balanced food. Chicken breast alone isn't an appropriate diet for cats and given some time yours could become ill due to nutritional deficiencies.