Causes of Megacolon in Cats

Cats may start with mild to moderate constipation and over time without treatment, develop megacolon and chronic constipation. Anything that prevents the passage or movement of stool in the large intestine can lead to megacolon:

• Injury to the nerves that control the muscles of the large intestine caused by trauma or disease
• Arthritis
• Obstruction of the large intestines due to trauma, cancer, or foreign body
• Certain hernias

In addition, inflammation, diabetes mellitus, chronic kidney disease, and prolonged enlargement of the large intestines may contribute to megacolon. The Manx breed of cats known to be born without a tail often have a deformed or abnormal area of the spine called the sacrum which may contribute to the development of megacolon in this breed.

Sometimes, the cause of the megacolon cannot be determined and is called idiopathic megacolon.

Click on the following link to read more about constipation in cats, causes, treatment, and prevention:

A Guide to Treating and Preventing Constipation in Cats

Symptoms of Megacolon in Cats

In the beginning, owners may notice harder and larger than normal stool in the litter box. As the illness progresses, cats often sit in the litter box longer than usual without producing stool at all. By this time, they may also have nausea, vomiting, and decreased appetite. Cats with megacolon often vocalize or cry out due to pain when having a bowel movement.

You may notice a decrease in the amount of stool in the litterbox. Alternatively, some cats pass watery diarrhea around the hard stool.

Other signs not specific but often seen with megacolon include decreased or no appetite, decreased activity, not behaving as normal, weight loss, and vomiting.

How is megacolon diagnosed?

Megacolon in cats is diagnosed based on a history of decreased and/or difficulty producing stool or constipation. Cats with the symptoms listed above along with a physical exam finding of firm stool in the large intestine is suggestive of megacolon. X-rays of the abdomen help confirm the diagnosis and additional tests will be needed to determine hydration status and any other illness that may be causing megacolon.

What treatments are available for cats with megacolon?

Treatment of megacolon depends on the cause of the constipation: foreign objects and tumors need to be removed and trauma to the pelvis may require surgery. Illnesses that contribute to dehydration and constipation such as chronic kidney disease also need appropriate treatment.

When caught early, treatment for mild to moderate constipation includes changes in diet as well as enemas and laxatives. For more severe constipation, cats will also need intravenous (IV) fluid therapy as well as manual removal of stool under anesthesia. Your vet may prescribe medications to relieve pain, soften the stool, and prevent nausea and vomiting.

In cats that have repeated episodes of constipation, do not respond to supportive care and diet change, and increasingly need IV fluids and anesthesia to remove stool, a surgery called subtotal colectomy is necessary. This procedure is high risk with several possible complications and owners must discuss with their vet to understand not only the risks but what to expect after surgery and in the months following the procedure.

Cats that have a subtotal colectomy have a good to excellent outcome or prognosis. A subtotal colectomy procedure involves removing most of the large intestine resulting in diarrhea or soft, pudding-like stools for about 2-3 months after surgery. In some cats, diarrhea is a life-long consequence.

Is megacolon preventable?

The right nutrition and diet play an important role in preventing megacolon in cats. Always talk to your vet before changing your cat’s diet as this can lead to other problems.

If you notice your cat struggling to have a bowel movement, or if your cat seems painful when having a bowel movement, contact a vet right away. Early intervention of constipation can decrease your cat’s risk of developing megacolon.

Early repair of pelvic fractures can prevent obstruction of the pelvic canal and constipation.

When to Contact a Veterinarian

Contact a vet if your cat doing any of the following:

• Producing less stool than normal
• Sitting in the litter box posturing but producing only small amounts of hard stool Not producing stool at all
• Crying when having a bowel movement

Additionally, if your cat is vomiting, not behaving as normal, sleeping or hiding more than usual, has a decreased appetite, or seems painful, you should schedule an appointment to have your cat examined.

Read more:

The Cat Digestive System: Anatomy and Functions

5 Interesting Facts About Your Cat’s Digestive System

How to Choose the Right Food for Your Cat

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