Constipation is a common problem in clinical practice. It does not, however, have one consistently used definition. Because of the wide range of normal bowel habits, constipation is difficult to define precisely. Stool frequency is most often used to describe constipation, and has been defined as less than three stools per week. Frequency alone, however, is not sufficient criterion to describe constipation, as patients often complain not only about frequency, but also about stool size or consistency, straining, lower abdominal pain or fullness, and a sense of incomplete evacuation.

While constipation may be caused by numerous reasons, probably the most common reason, particularly in the United States, is due to lack of fiber in the diet. Often, cases are self-treated by the patient without consultation or advice from a health care practitioner. The large dollar volume spent each year on laxatives, advertising attention received, and shelf space allotted in retail stores is evidence that constipation is a common occurrence. Another reason for frequent laxative use may be misconceptions concerning normal bowel habits. Some people believe that if they do not have a daily bowel movement, that it is detrimental to their health because toxins will accumulate.

Constipation is not a disease, but a symptom of some underlying problem. Approaches to treatment of constipation should begin with attempts to determine its cause. Disorders of the GI tract (irritable bowel syndrome or diverticulitis), metabolic disorders (diabetes), or endocrine disorders (hypothyroidism) may be involved.(1)

Constipation is a frequent problem in the elderly, and may be caused by a lack of fiber in the diet or decreased fluid intake. Other factors to consider may include lack of physical activity or diminished abdominal muscle wall strength. However, the frequency of bowel movements is not decreased with normal aging.(2) Abdominal surgery, hospitalization, stress and anxiety, or chronic illnesses that lead to physical or mental impairment and result in physical immobility or inactivity may worsen constipation.

In a person who has a recent onset of constipation, the possibility of some type of obstruction of the colon should be sought. Such an obstruction may be due to a variety of things including diverticular disease, irritable bowel syndrome, foreign bodies, or anal strictures. Hemorrhoids, anal fissures, or ulcerative proctitis may all result in painful defecation and inhibit the desire to evacuate.

Neurologic disorders of the GI tract may also cause constipation. Hirschsprung's disease, also called aganglionosis, is characterized by a congenital absence of neurons to terminal segments of the bowel. Most cases are diagnosed by six months of age; however, mild cases may not be detected until adulthood. In addition to peripheral neurologic disorders, central nervous system disorders may be responsible for constipation. The CNS plays an important part in GI regulation, rather through reflexes, or coordination of other organs. It also modifies GI function in response to conscious effort or emotional stimuli. In patients with multiple sclerosis, constipation may be associated with dysfunction of other organs. Similarly, CNS lesions caused by Parkinsonism or cerebrovascular accident may cause constipation.

Constipation is a frequent problem during pregnancy, possibly resulting from complex factors that include depressed gut motility, increased fluid absorption from the colon, decreased physical activity, and dietary changes.(3)

Drugs that may lead to constipation include opiates, various agents with anticholinergic properties, such as antidepressants and antipsychotics, antacids containing calcium or aluminum, iron supplements, sucralfate, and calcium channel blockers. Generally, the constipating effects of these drugs are<