The colon enlarges as it becomes distended with more hard, dry stool hence the name megacolon. The longer the stool remains in the colon, the more water is absorbed causing progressively harder, drier stools that are more difficult to pass. Eventually, defecation becomes impossible.
Underlying Causes
The underlying causes that lead to the disruption of the nerves or muscles are varied and may be congenital, traumatic or unknown. Older cats are most often affected but the disease can appear in young animals by the age of three or four. The breeds most commonly affected are the domestic shorthair, Siamese and Manx. Seventy percent more males than females develop feline megacolon.
Signs and Symptoms of Feline Megacolon
The most frequent sign associated with feline megacolon is chronic constipation. The cat may also show lack of appetite, abdominal distention or swelling, nausea, vomiting, straining while attempting to move the bowels, pain with bowel movements, and bulging of the rectum to the outside of the body as a consequence of constant straining. There may be blood or mucous present when attempting to defecate and small amounts of hard, dry stool may be passed.
Treatment of Megacolon Bowel Disorder
Treating feline megacolon is a multifaceted approach with the aims of treating the initial event and restoring colonic function, and prevention of further episodes. Medications are used to soften the stool and restore the normal movement of the bowel smooth muscle. Hospitalization may be necessary for administration of IV fluids and medications. Surgery, or enemas with manual extraction of the impacted feces may be necessary.
Preventing Chronic Constipation
Preventative measures will decrease the number of repeated episodes that the cat experiences. Prevention includes maintaining the cat at or near an ideal weight since obesity is a risk factor. The diet should include fiber supplements as recommended by the veterinarian and treatment for hairballs on a regular basis. The owner should comb the cat frequently to remove excess hair. Keeping the litter box clean will encourage the cat to eliminate frequently.
Enemas should not be used at home except on the advice of their veterinarian, as cats will usually need some sedation for the procedure. Another approach to treatment is to feed a highly digestible diet that is low in residue, so that only small amounts of stool are formed.
Prognosis
The long-term outlook for cats that have feline megacolon is fair. While most cats will respond to therapy of the initial onslaught, even those that require surgery, repeat episodes are not uncommon. Early treatment of repeat episodes of constipation will add years and quality to the cats' life.