# Medscape: Myths about Constipation



## cookies4marilyn (Jun 30, 2000)

http://www.medscape.com/viewarticle/496828?src=mp Common Myths About Constipation DispelledNews Author: Laurie Barclay, MDCME Author: Dï¿½sirï¿½e Lie, MD, MSEdJan. 4, 2005 ï¿½ A review article in the January issue of The American Journal of Gastroenterology dispels many of the common myths about constipation, such as that increased intake of fluids and fiber is necessary and that laxatives are harmful."Chronic constipation is uncomfortable, but not dangerous," lead author Stefan A. Mï¿½ller-Lissner, MD, from Humboldt University in Berlin, Germany, says in a news release. "This might be the reason why medical doctors often do not take it seriously. There are many unproven beliefs about constipation, but most of them are not tenable upon closer investigation with scientific methods."The American College of Gastroenterology states that constipation is one of the most common gastrointestinal (GI) tract complaints in the U.S. and in Western countries. In the U.S., there are at least 2.5 million physician visits for constipation each year, and costs of laxatives are in the hundreds of millions of dollars.Based on a review of medical trials, the authors found no evidence for the "autointoxication" theory suggesting that diseases may arise when poisonous substances are absorbed from stools within the colon.Dolichocolon, defined as an elongated colon, does not appear to cause constipation. The role of sex hormones in changing GI tract function during the menstrual cycle seems to be minimal, whereas during pregnancy, sex hormones may contribute to slowed gut transit. Although hypothyroidism can cause constipation, hypothyroidism is rare in patients presenting with constipation.The authors suggest that a diet lacking fiber should not be assumed to be the cause of chronic constipation. Although some patients may benefit from a fiber-rich diet, many patients with more severe constipation get worse symptoms when increasing dietary fiber intake. Unless there is evidence of dehydration, there is no evidence that increasing fluid intake can successfully treat constipation.Constipation may be associated with decreased physical activity in the elderly, but many other factors are likely to contribute. Nonetheless, intervention programs to increase physical activity as part of a broad rehabilitation program may be helpful.At recommended doses, stimulant laxatives are unlikely to be harmful to the colon. Although some patients with chronic constipation depend on laxatives for satisfactory bowel function, this is not the result of prior laxative intake. Tolerance to stimulant laxatives is uncommon; there is no evidence of "rebound constipation" after stopping laxative intake, and there is no potential for addiction even though laxatives may be misused.Chronic constipation appears to be associated with an increased risk of colorectal cancer, but there are no data suggesting that stimulant laxatives are an independent risk factor for colorectal cancer."Patients may no longer be bothered by ineffective advice regarding fiber and fluid ingestion nor threatened by the side effects of laxatives," Dr. Mï¿½ller-Lissner says. "Also, unnecessary colonic resections may be avoided."Am J Gastroenterol. 2005;100:232-242Learning Objectives for This Educational ActivityUpon completion of this activity, participants will be able to: Identify some common myths about constipation. Explain current evidence to dispel the most commonly held myths about constipation. Clinical ContextConstipation is one of the most frequent GI tract complaints in the U.S. and other Western countries. There are at least 2.5 million visits to the physician for constipation annually in the U.S., with hundreds of millions of dollars spent on laxatives and other treatments. With chronic constipation, patients may have constipation for weeks and have recurring bouts for long periods. The colon serves to conserve water by reabsorbing fluids, allows bacteria to split fiber into absorbable nutrients, and expels residue according to a complex interplay of motility and intrinsic and extrinsic sphincter function. However, perceptions of the definition of "optimal bowel function" (for example, based on stool frequency, hardness, and consistency) leading to efforts to restore normality can often be opinion-based rather than evidence-based, according to the authors.The current authors reviewed the literature and the myths surrounding this common symptom and provide some insights into and clinical guidelines for managing this common complaint. They noted that evidence to support commonly held beliefs is often lacking.Study HighlightsMyths about etiologic factors Dolichocolon, described as an elongated but not dilated colon, has been implicated in the etiology of constipation with little evidence. Studies in women with constipation suggest no difference between women with short or long colons. There is thus no support for the routine use of colon shortening procedures such as resection and bypass for treating chronic constipation. Constipation in children is more common in boys than girls. However between the ages of 15 and 50 years, constipation is more common in females. Stool transit time and weight have not been demonstrated to differ between the luteal and follicular phases of the menstrual cycle. The observation that females with chronic constipation have more gynecologic surgery appears to arise from a misconception that gynecologic or pelvic pain is related to the constipation. Sex hormones do not appear to play a role in constipation under normal physiologic conditions but may contribute to altered gut function and slowed transit time during pregnancy. Patients with severe chronic constipation have specific abnormalities of circulating gut hormones (such as higher somatostatin and lower pancreatic glucagons), which regulate bowel motility. However whether these changes are primary or secondary to the constipation is unknown. Among patients presenting with constipation, hypothyroidism is rare. Routine thyroid testing is not recommended in the absence of other clinical features of hypothyroidism. Myths about treatment of constipation A diet poor in fiber should not be assumed to be the cause of constipation but could be a contributing factor. Patients with chronic constipation may do worse with an increase in dietary fiber intake. Those with a relative fiber deficiency may show improvement. Gas production from fiber metabolism often limits acceptability. There is no evidence that constipation can be treated by increasing the fluid intake unless there is evidence of dehydration. Those who are more active have a lower incidence of constipation. Elderly patients with poor mobility and depression have a higher rate of constipation, but other factors may play roles. Vigorous physical activity such as running a marathon increases gut and colonic activity and can lead to dramatic increases in large bowel function. Myths about laxative use It is unlikely that the use of stimulant laxatives at normal doses are harmful to the colon. Although chronic constipation appears to be associated with a higher risk of colorectal cancer, there are no data to support that stimulant laxatives use is an independent risk factor. Tolerance to stimulant laxatives is uncommon and is restricted to the most severe users of laxatives for whom other laxatives are ineffective. Laxatives do not cross the blood-brain barrier, and there is no pharmacologic basis for addiction. However, laxatives are more likely to be misused by psychiatric patients. Laxatives have not been shown to contribute to true weight loss. Pearls for PracticeMyths about constipation include belief in dolichocolon, menstrual hormonal changes, and gynecologic problems as etiologic factors. There is little evidence to support the addiction and tolerance potential of laxatives and the routine recommendation of increasing fluids and fiber intake in the treatment of chronic constipation.


----------

