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Diarrhea in Adults (Acute)



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Am Fam Physician. 2008 Aug 15;78(4):503-504.

This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). See Clinical Quiz on page 441.

Diarrhea is watery or liquid stools, usually with an increase in stool weight of more than 200 g daily and an increase in daily stool frequency.

  • An estimated 4 billion cases of diarrhea occurred worldwide in 1996, resulting in 2.5 million deaths.

In persons from resource-poor countries, antisecretory agents (e.g., racecadotril) seem to be as effective at improving symptoms of diarrhea as antimotility agents (e.g., loperamide), but with fewer adverse effects.

  • Empiric treatment with antibiotics also seems to reduce the duration of diarrhea and improve symptoms in this population, although it can produce adverse effects, such as rash, myalgia, and nausea.

  • Instructing persons to refrain from consuming any solid food for 24 hours does not appear to be useful, although the evidence for this is sparse.

  • We do not know how effective oral rehydration solutions or antibiotics plus antimotility agents are in persons from resource-poor countries because we did not find any randomized controlled trials.

Antisecretory agents, antibiotics, and antimotility agents also appear to be effective in treating persons from resource-rich countries who are traveling to resource-poor countries.

  • We do not know whether antibiotics plus antimotility agents are more effective than either treatment alone or placebo.

  • Bismuth subsalicylate is effective in treating traveler's diarrhea, but less so than loperamide, and with more adverse effects (primarily black tongue and black stools).

  • We do not know the effectiveness of oral rehydration solutions or diet restriction in reducing symptoms of diarrhea in persons traveling to resource-poor countries.

For persons from resource-poor countries with mild or moderate diarrhea, antisecretory agents seem to be as beneficial as antimotility agents, and cause fewer adverse effects (particularly rebound constipation).

  • We did not find sufficient evidence to judge the effectiveness of antibiotics, antibiotics plus antimotility agents, or oral rehydration solutions in this population.

Oral rehydration solutions are considered to be beneficial in persons from resource-poor countries who have severe diarrhea.

  • Studies have shown that amino acid–based and rice-based oral rehydration solutions are beneficial, but the evidence is less clear about the effectiveness of bicarbonate or reduced osmolarity solutions.

We do not know whether intravenous rehydration is more beneficial than oral rehydration or enteral rehydration through a nasogastric tube.

  • We do not know whether antimotility agents, antisecretory agents, antibiotics, or antibiotics plus antimotility agents are effective for treating persons in resource-poor countries who have severe diarrhea.

Clinical Questions

What are the effects of treatments for acute diarrhea in adults living in resource-rich countries?

Likely to be beneficial

Antimotility agents

Antisecretory agents

Trade-off between benefits and harms

Antibiotics (empiric use for mild-to-moderate diarrhea)

Unknown effectiveness

Antibiotics plus antimotility agents

Restricted diet

Oral rehydration solutions

What are the effects of treatments for mild-to-moderate traveler's diarrhea in adults from resource-rich countries traveling to resource-poor countries?

Likely to be beneficial

Antibiotics (empiric use)

Antimotility agents

Bismuth subsalicylate (reduced duration of diarrhea compared with placebo, but less effective than loperamide)

Trade-off between benefits and harms

Antisecretory agents

Unknown effectiveness

Antibiotics plus antimotility agents

Restricted diet

Oral rehydration solutions

What are the effects of treatments for mild-to-moderate diarrhea in adults living in resource-poor countries?

Likely to be beneficial

Antimotility agents

Antisecretory agents

Unknown effectiveness

Antibiotics (empiric use)

Antibiotics plus antimotility agents

Oral rehydration solutions

What are the effects of treatments for severe diarrhea in adults living in resource-poor countries?

Beneficial

Amino acid–based oral rehydration solutions

Rice-based oral rehydration solution

Standard oral rehydration solution*

Unknown effectiveness

Antibiotics (empiric use)

Antibiotics plus antimotility agents

Antimotility agents

Antisecretory agents

Bicarbonate oral rehydration solution

Intravenous rehydration (compared with nasogastric tube rehydration or oral rehydration solution alone)

Reduced osmolarity oral rehydration solution


*— Categorization based on consensus. Randomized controlled trials unlikely to be conducted.

Clinical Questions

View Table

Clinical Questions

What are the effects of treatments for acute diarrhea in adults living in resource-rich countries?

Likely to be beneficial

Antimotility agents

Antisecretory agents

Trade-off between benefits and harms

Antibiotics (empiric use for mild-to-moderate diarrhea)

Unknown effectiveness

Antibiotics plus antimotility agents

Restricted diet

Oral rehydration solutions

What are the effects of treatments for mild-to-moderate traveler's diarrhea in adults from resource-rich countries traveling to resource-poor countries?

Likely to be beneficial

Antibiotics (empiric use)

Antimotility agents

Bismuth subsalicylate (reduced duration of diarrhea compared with placebo, but less effective than loperamide)

Trade-off between benefits and harms

Antisecretory agents

Unknown effectiveness

Antibiotics plus antimotility agents

Restricted diet

Oral rehydration solutions

What are the effects of treatments for mild-to-moderate diarrhea in adults living in resource-poor countries?

Likely to be beneficial

Antimotility agents

Antisecretory agents

Unknown effectiveness

Antibiotics (empiric use)

Antibiotics plus antimotility agents

Oral rehydration solutions

What are the effects of treatments for severe diarrhea in adults living in resource-poor countries?

Beneficial

Amino acid–based oral rehydration solutions

Rice-based oral rehydration solution

Standard oral rehydration solution*

Unknown effectiveness

Antibiotics (empiric use)

Antibiotics plus antimotility agents

Antimotility agents

Antisecretory agents

Bicarbonate oral rehydration solution

Intravenous rehydration (compared with nasogastric tube rehydration or oral rehydration solution alone)

Reduced osmolarity oral rehydration solution


*— Categorization based on consensus. Randomized controlled trials unlikely to be conducted.

Definition

Diarrhea is watery or liquid stools, usually with an increase in stool weight of more than 200 g daily and an increase in daily stool frequency. This review covers empiric treatment of suspected infectious diarrhea in adults.

Incidence

An estimated 4 billion cases of diarrhea occurred worldwide in 1996, resulting in 2.5 million deaths. In the United States, the estimated incidence of infectious intestinal disease is 0.44 episodes per person every year (one episode per person every 2.3 years), resulting in about one consultation with a physician per person every 28 years. A recent community study in the United Kingdom reported an incidence of 19 cases per 100 person-years, of which 3.3 cases per 100 person-years resulted in consultation with a physician. Both estimates derive from population-based studies that included adults and children. The epidemiology of traveler's diarrhea is not well understood. The incidence is higher in travelers visiting resource-poor countries, but it varies widely by location and season of travel. The incidence of diarrhea in adults in resource-poor countries is largely unknown, owing to the lack of large-scale surveillance studies in these countries.

Etiology

The cause of diarrhea depends on geographic location, standard of food hygiene, sanitation, water supply, and season. Commonly identified causes of sporadic diarrhea in adults in resource-poor countries include Campylobacter, Salmonella, Shigella, Escherichia coli, Yersinia, protozoa, and viruses. No pathogen is identified in more than one half of persons with diarrhea. In returning travelers, about 50 percent of episodes are caused by bacteria, such as enterotoxigenic and enteroadherent E. coli, Salmonella, Shigella, Campylobacter, Vibrio, Yersinia, and Aeromonas.

Prognosis

In resource-rich countries, death from infectious diarrhea is rare, although serious complications, including severe dehydration and renal failure, can occur and may necessitate hospitalization. Older persons and those in long-term care have an increased risk of death. In resource-poor countries, diarrhea is reported to cause more deaths in children younger than five years than any other condition. Few studies have examined which factors predict poor outcome in adults.

Author disclosure: Guy de Bruyn is coauthor of a systematic review cited in the full text of this review.

editor's note: Racecadotril is not available in the United States.

search date: January 2007

Adapted with permission from de Bruyn G. diarrhoea in adults (acute). Clin Evid Handbook. June 2008:263–266. Please visit http://www.clinicalevidence.bmj.com for full text and references.

 

This is one in a series of chapters excerpted from the Clinical Evidence Handbook, published by the BMJ Publishing Group, London, U.K. The medical information contained herein is the most accurate available at the date of publication. More updated and comprehensive information on this topic may be available in future print editions of the Clinical Evidence Handbook, as well as online at http://www.clinicalevidence.bmj.com (subscription required). Those who receive a complimentary print copy of the Clinical Evidence Handbook from United Health Foundation can gain complimentary online access by registering on the Web site using the ISBN number of their book.



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