04/10/2015 Approach to the adult with chronic diarrhea in developed countries http://www.uptodate.com/contents/approachtotheadultwithchronicdiarrheaindevelopedcountries?topicKey=GAST%2F2591&elapsedTimeMs=11&… 1/26 Official reprint from UpToDate www.uptodate.com ©2015 UpToDate Authors Peter A L Bonis, MD J Thomas Lamont, MD Section Editor Paul Rutgeerts, MD, PhD, FRCP Deputy Editor Shilpa Grover, MD, MPH Approach to the adult with chronic diarrhea in developed countries All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Sep 2015. | This topic last updated: Mar 27, 2015. INTRODUCTION — Diarrhea, derived from the Greek "to flow through," is a common manifestation of gastrointestinal disease. Its definition has traditionally been based upon the frequency, volume, and consistency of stools. However, the relationship between these features and patients' perception of diarrhea is variable. As a result, a consensus statement issued by the American Gastroenterological Association suggests that chronic diarrhea should be defined as a decrease in fecal consistency lasting for four or more weeks. This topic review will provide an overview of the evaluation and treatment of chronic diarrhea. Individual disorders associated with chronic diarrhea, a discussion regarding diarrhea in HIVinfected patients, and an approach to patients with acute diarrhea are presented separately. (See "Evaluation of the HIVinfected patient with diarrhea" and "Approach to the adult with acute diarrhea in resourcerich countries" .) EPIDEMIOLOGY — The prevalence of chronic diarrhea in the general population in developed nations has not been well established. The variable rates observed in several studies reflect differences in study design, definitions, and characteristics of populations that have been sampled [14 ]. Based upon a commonly used definition (ie, the presence of excessive stool frequency) a reasonable approximation is that chronic diarrhea affects approximately 5 percent of the population. Economic impact — The economic impact of chronic diarrhea has not been well quantified, particularly when considering societal costs. One estimate based upon limited data is that chronic diarrhea costs more than $350,000,000 annually from work loss alone [5,6 ]. Effect on quality of life — Chronic diarrhea can decrease quality of life. However, accurate assessment of the degree to which this occurs has not been established. One explanation is that a wellvalidated diseasespecific qualityoflife instrument has not yet been developed. Furthermore, no studies have attempted to measure quality of life in large groups of patients. Chronic diarrhea was an independent predictor of decreased quality of life in HIVinfected patients [7,8 ]. ETIOLOGY — A myriad of disorders are associated with chronic diarrhea. Numerous medications are also associated with diarrhea ( table 1 ). The prevalence of specific disorders varies based upon the practice setting. The types of disorders described in individual case series frequently reflect referral bias. As a general rule, the principal causes of diarrhea depend upon the socioeconomic status of the population. In developing countries, chronic diarrhea is frequently caused by chronic bacterial, mycobacterial, and parasitic infections, although functional disorders, malabsorption, and inflammatory bowel disease are also common. In developed countries, common causes are irritable bowel syndrome (IBS), inflammatory bowel disease, malabsorption syndromes (such as lactose intolerance and celiac disease), and chronic infections (particularly in patients who are immunocompromised). The following sections will highlight the clinical features that should raise suspicion for some of the common disorders. Discussions on other disorders associated with chronic diarrhea are presented separately in the corresponding topic reviews. Irritable bowel syndrome — Patients with IBS can present with a wide array of symptoms, which include both gastrointestinal and extraintestinal complaints. However, the symptom complex of chronic lower abdominal pain and altered bowel habits remains the nonspecific yet primary characteristic of IBS. Patients usually experience the onset of symptoms as young adults, but the prevalence is similar in older adults. Females are diagnosed more than twice as often as males. Symptoms of IBS often correlate with episodes of psychologic stress. Thus, patients often seek medical help for their chronic symptoms during such periods. (See "Clinical manifestations and diagnosis of irritable bowel syndrome in adults" .) ® ®