Constipation

Constipation is a symptom, not a disease. In the absence of an identifiable cause, it is  Read more below

Epidemiology

Constipation accounts for 2.5 million physician visits each year. Americans spend about a billion dollars each year on laxatives alone. There is of course the additional cost of work-related absences, visits to the physician office and emergency room, diagnostic tests and the treatment undertaken. In many cases, fecal impaction is a significant factor in the removal of senior citizens from their loved ones to nursing homes.

Constipation is more common among females. People of all ages can get this condition; however the prevalence increases in both sexes with aging. Physician visits for constipation as well as laxative use rise dramatically after the age of 65 years.

No obvious cause can be identified in many patients. Constipation in such cases is presumed to be due to any number of causes leading to a sluggish movement of stool through the colon, the rectum or both.

A detailed history with special attention to risk factors is important. Maintaining a diary to record symptoms and food intake for several weeks prior to a physician's visit is helpful. An unexplained recent alteration in bowel habit or presence of anemia is cause for concern and call for prompt investigation. Initial studies include complete blood counts, serum chemistries including calcium level, and thyroid function tests. Structural obstruction is excluded by a barium x-ray and/or endoscopy.

A radioopaque marker study may be performed for patients unresponsive to conservative treatment. This is undertaken while on high fiber diet and refraining from laxatives or enemas. This test identifies the part of colon where the passage of stool is sluggish and helps in planning management strategies. On the other hand, an x-ray evidence of timely passage of markers in a patient complaining of infrequent defecation suggests misconception or misrepresentation.

Barium defecography (x-rays while expelling barium from rectum) and anorectal manometry (pressures in rectum and anal canal) may be evaluated in selected cases.

Patient education, reassurance, increased fluid intake and exercise while trying to reduce laxative use help in uncomplicated cases. Initial response may take several days, whereas resolution of constipation may take several weeks.

Food intake stimulates the colon. Go to the toilet in the morning especially after breakfast and after meals. Increased dietary fiber (wheat bran is the most effective) and commercial bulk laxatives (Metamucil, Fibercon) are safe and effective in the majority of cases. However, all fibers are not created equal. Fiber contained in vegetables and fruits is not a adequate substitute for bran.

Sorbitol and lactulose are poorly absorbed sugars and can cause bloating and abdominal distention. Polyethylene glycol (Miralax) is very effective and does not cause salt or fluid overload. Mineral oil softens the stools, but the risk for aspiration pneumonia makes it an unattractive option for oral administration.

Stimulant laxatives are frequently used when patients do not respond to initial measures. Risk for "cathartic colon" has been overblown, and they are usually safe if taken no more than 2-3 times per week under physician supervision. Options include senna (Ex-Lax, Senokot), bisacodyl (Dulcolax) and cascara. Melanosis coli (dark discoloration of colon) may occur due to prolonged use of certain laxatives, but is harmless. Self-administration of tap water enema every 3-4 days is helpful for patients not responding to oral laxatives.

Habit training plus judicious use of laxatives is helpful. As a first step, colon is cleansed out completely by twice daily enemas or 4-8 liters of polyethylene glycol solution (GoLytely, CoLyte). Once colonic cleansing has been accomplished, patient is started on a regular dose of laxatives, titrated to achieve one stool per day.

Surgery is the treatment of choice in Hirschprung's disease (usually seen in children and young adults). Surgery may also be helpful for selected patients with severely sluggish colon or those with difficulty expelling stool due to anorectal disorders.

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