Constipation in Cats

What is constipation?

Constipation can be defined as an abnormal accumulation of feces in the colon, resulting in difficult bowel movements. This may result in reduced frequency or absence of defecation. The feces are retained in the large intestine or colon. Since one of the major functions of the colon is water absorption, the retained feces become hard and dry, which makes passing the feces even more difficult. Constipated cats strain in an attempt to defecate resulting in abdominal pain. Some constipated cats may pass small amounts of liquid feces or blood because of excessive straining. Sometimes, the liquid feces are mistaken for diarrhea, but in actuality, when the cat strain, a small amount of liquid fecal material is able to squeeze around the hard fecal mass. 

What causes constipation?

"Constipation is a condition seen most commonly in middle-aged and older cats."

Constipation is a condition seen most commonly in middle-aged and older cats. Factors associated with the development of constipation include:

1.  Hairballs, especially in longhaired cats.

2.  Ingestion of foreign bodies.

3.  Pelvic injuries resulting in a narrowed pelvic canal.

4.  Obesity

5.  In some cases, there is no obvious cause identified. Constipation is common symptom associated with idiopathic (unknown cause) megacolon.

What is megacolon?

Megacolon is a term referring to a dilated and weak colon that causes severe constipation. Megacolon may be seen as a primary entity or following long-term constipation. When the colon becomes distended with fecal material over a prolonged period, its ability to contract may be reduced or lost resulting in megacolon. Feces then accumulate in this abnormally distended and enlarged colon.

How are constipation and megacolon diagnosed?

In most cases, a diagnosis of constipation can be made on the basis of the cat's clinical signs and medical history. Affected cats usually strain unsuccessfully to defecate and may cry in pain. Any feces passed are hard and dry. The cat may also show signs of lethargy, reluctance to eat, abdominal pain and distention and vomiting.

Unless the cat is obese or tense, a veterinarian can often palpate or feel the accumulated fecal material in the colon. Further tests may be needed in order to diagnose the cause of the constipation and these may include abdominal and pelvic x-rays to look for pelvic injuries, colonic strictures or tumors. X-rays are also the primary test for the diagnosis of megacolon.

How can constipation and megacolon be treated?

Treatment varies depending on the cause of constipation. If an obstruction such as a colonic tumor is present, surgery may be required.

Initial treatment of a cat with constipation may involve administration of enemas and manual extraction of feces by a veterinarian. Removal of feces often requires an anesthetic or sedative. Intravenous fluid therapy is usually required to correct fluid imbalances and dehydration that worsen the constipation. If the constipation recurs or becomes a long-term problem, dietary management or medications may be needed to prevent recurrence. A number of treatments are available to soften the feces and promote regular bowel movements. In mildly affected cats, high fiber diets, lubricating laxatives or stool softeners may prevent recurrence. Those more severely affected may need drugs that stimulate contraction of the colon. The dose of these drugs is adjusted as needed to produce the desired effect. Ideally, cats should defecate at least once every other day. Over time, resistance to the treatment may develop, necessitating an increase in the drug dosage or a change in therapy. You should not make changes to your cat's treatment protocol without consulting your veterinarian.

"It is important to ensure that there is always access to a clean litter tray so that frequent defecation is encouraged."

In longhaired cats, regular grooming may reduce hair ingestion, while "hairball remedies" or hairball diets may lessen the likelihood of hairballs causing constipation.

When might surgery be necessary?

If megacolon develops or if the constipation is severe and medical treatment is unsuccessful, surgery may be recommended. Surgical treatment involves removal of the affected portion of the colon, in a procedure called a partial or sub-total colectomy. Most cats do very well with few side effects following this surgery.What is the long-term outlook for a cat with this problem?

The long-term outlook varies according to the cause of the constipation; however, most cats can be adequately managed without surgery and resume normal, healthy lives. For cats that require surgery to correct megacolon, the prognosis is good.