Western-style societies have the highest incidence of constipation as compared to less developed societies. Dietary composition, especially fiber content, may be a leading contributing cause of constipation. Inadequate dietary fiber intake produces stools that are less bulky, lower in water content, lower in volume, and more difficult to eliminate. In societies such as western Africa where the average dietary fiber intake is as much as 35 g of insoluble fiber, individuals have two to three large soft bowel movements per day on average, and reports of constipation are uncommon.2 In the United States, dietary fiber intake averages less than 12g per day, and complaints of constipation may affect 3% to 5% of the population at any given time.2 Insoluble dietary fiber acts by drawing water into the intestinal lumen, resulting in bulky, soft, large stools that have higher water content. Colonic peristaltic movements, in turn, are in part stimulated by colonic distention.
Strange as it may seem, a hectic schedule and lack of time to eliminate is an increasingly frequent cause of constipation, particularly in individuals trying to manage more than one job.
Numerous medications (anticholinergics, anti-depressants, narcotics) may lead to iatrogenic constipation by impeding neural signaling, resulting in impaired colonic muscular coordination (Table 3.1). Initial treatment of constipation with an identified pharmacologic cause consists of discontinuing the offending drug or replacing the drug with a nonconstipating alternative, if available. Psychiatric disorders such as depression, psychosis, and anorexia nervosa, as well as their pharmacologic treatments, may contribute to or worsen constipation. This has become a real clinical problem with the increasing and almost ubiquitous prescription of
Etiology of acquired constipation
Pace of life Medications Weight loss/anorexia/ laxative abuse
Infectious etiology i
> Strictures Adhesions Volvulus Rectal prolapse
Full-thickness Internal Rectocele
Physiologic and other abnormalities
Brain and CNS tumors
Functional, with or without mechanical component
• Nonrelaxing puborectalis
• Slow-transit colonic constipation
• Descending perineum
Figure 3.1. Algorithm describing etiologies of various acquired constipation.
Table 3.1. Pharmacologic causes of constipation Amiodarone
Antacids (e.g., aluminum)
Calcium channel blockers Diuretics
Ganglionic blockers Antiparkinsonians Bismuth Bromocriptine
Bulk laxatives with inadequate hydration
Filgrastim [granulocyte colony-stimulating factor (G-CSF)] Iron
Vincristine antidepressants and psychotropic drugs by many physicians.
Weight Loss, Eating Disorders, and Laxative Abuse
Lack of oral intake, or bulimia, can be associated with reduced fecal volume. By their mechanism of action, overuse of laxatives may result in constipation due to dehydration, hypokalemia, or hypermagnesemia, altering neural transmission and function. The role of laxatives in damaging enteric neurons is uncertain. Long-term use has been associated with changes in neurons of the myenteric plexus and smooth muscle of the colon.3 Findings such as loss of neurons, morphologic changes of argyrophilic cells, including clubbing and shrinkage, and replacement of ganglia by Schwann cells have been histol-ogically demonstrated.4 Similar morphologic findings have been discovered in patients with inflammatory bowel disease and diabetic neuropathy, and may not be specific for laxative use.5
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Are You Depressed? Heard the horror stories about anti-depressants and how they can just make things worse? Are you sick of being over medicated, glazed over and too fat from taking too many happy pills? Do you hate the dry mouth, the mania and mood swings and sleep disturbances that can come with taking a prescribed mood elevator?