(See also Overview of Gastroenteritis Overview of Gastroenteritis Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. Most cases are infectious, although gastroenteritis may occur after ingestion of drugs and chemical... read more and see the Center for Disease Control and Prevention’s [CDC] information for preparing international travelers for travelers’ diarrhea.)
Etiology of Traveler's Diarrhea
Traveler’s diarrhea may be caused by any of several bacteria, viruses, or, less commonly, parasites.
The most common cause of traveler's diarrhea is
Enterotoxigenic Escherichia coli (E. coli)
E. coli Escherichia coli Infections The gram-negative bacterium Escherichia coli is the most numerous aerobic commensal inhabitant of the large intestine. Certain strains cause diarrhea, and all can cause infection when they invade... read more is common in the water supplies of areas that lack adequate purification. Infection is common among people traveling to developing countries.
Norovirus gastroenteritis Norovirus Gastroenteritis Norovirus is a common cause of diarrhea. Symptoms are vomiting, abdominal cramps, and diarrhea that usually resolve in 1 to 3 days. Diagnosis is based on clinical suspicion, and polymerase chain... read more has been a particular problem on some cruise ships.
Both food and water can be the source of infection. Travelers who avoid drinking local water may still become infected by brushing their teeth with an improperly rinsed toothbrush, drinking bottled drinks with ice made from local water, or eating food that is improperly handled or washed with local water. People taking drugs that decrease stomach acid (antacids, H2 blockers, and proton pump inhibitors) are at risk of more severe illness.
Symptoms and Signs of Traveler's Diarrhea
Nausea, vomiting, hyperactive bowel sounds, abdominal cramps, and diarrhea begin 12 to 72 hours after ingesting contaminated food or water. Severity is variable. Some people develop fever and myalgias. Diarrhea is rarely bloody. Most cases are mild and self-limited, although dehydration can occur, especially in warm climates.
Diagnosis of Traveler's Diarrhea
Specific diagnostic measures are usually not necessary. However, fever, severe abdominal pain, and bloody diarrhea suggest more serious disease and should prompt immediate evaluation.
Treatment of Traveler's Diarrhea
Sometimes antimotility drugs
Antibiotics (eg, ciprofloxacin, azithromycin) for moderate to severe diarrhea
The mainstay of treatment of traveler's diarrhea is fluid replacement and an antimotility drug such as loperamide. For adults and children ≥ 12 years of age, the loperamide dosage is 4 mg orally initially, followed by 2 mg orally for each subsequent episode of diarrhea (maximum of 6 doses/day or 16 mg/day). An alternative for adults is diphenoxylate 2.5 to 5 mg orally 3 times a day or 4 times a day in tablet or liquid form. The dosage of loperamide for children < 12 years of age is weight-based and includes the following:
Children 13 to 21 kg: 1 mg orally after the first loose stool then 1 mg after each subsequent loose stool (maximum dose is 3 mg/day)
Children 21 to 27 kg: 2 mg orally after the first loose stool then 1 mg after each subsequent loose stool (maximum dose is 4 mg/day)
Children 27 to 43 kg, up to age 12: 2 mg orally after the first loose stool followed by 1 mg after each subsequent loose stool (maximum dose is 6 mg/day)
Antimotility drugs are contraindicated in patients with fever or bloody stools and in children < 2 years. Iodochlorhydroxyquin, which may be available in some low- and middle-income countries, should not be used because it may cause neurologic damage.
Pearls & Pitfalls
Generally, antibiotics are not necessary for mild diarrhea. However, in patients with moderate to severe diarrhea (≥ 3 loose stools over 8 hours), antibiotics are given, especially if vomiting, abdominal cramps, fever, or bloody stools are present. For adults, recommended oral antibiotics include ciprofloxacin 500 mg 2 times a day for 3 days or levofloxacin 500 mg once a day for 3 days, although fluoroquinolone resistance appears to be increasing in some areas, particularly in Campylobacter. Alternatives include azithromycin 500 mg once a day for 3 days or rifaximin 200 mg 3 times a day for 3 days. For children, azithromycin 5 to 10 mg/kg once a day for 3 days is preferred. (See also an expert panel's 2017 guidelines for the prevention and treatment of travelers' diarrhea.)
Prevention of Traveler's Diarrhea
Travelers should dine at restaurants with a reputation for safety and avoid foods and beverages from street vendors. They should consume only cooked foods that are still steaming hot, fruit that can be peeled, and carbonated beverages without ice served in sealed bottles (bottles of noncarbonated beverages can contain tap water added by unscrupulous vendors); uncooked vegetables (particularly including salsa left out on the table) should be avoided. Buffets and fast food restaurants pose an increased risk.
Some patients may require prophylaxis if they have underlying medical conditions that make them particularly susceptible to the consequences of traveler’s diarrhea. This includes patients with immunocompromise including inflammatory bowel disease or HIV, recipients of organ transplants, and patients with severe cardiovascular or kidney disease. The nonabsorbable antibiotic rifaximin can be used for prophylaxis in these patients. The dosage of rifaximin is 200 mg orally 3 times a day. Previously, fluoroquinolones were prescribed; however, adverse effects, including tendon rupture and peripheral neuropathy, limited their use. Alternatively, some travelers may consider the nonantibiotic bismuth subsalicylate as an alternative for prophylaxis.
Traveler's diarrhea is usually caused by enterotoxigenic E. coli, but viruses, parasites, and other bacteria may be involved.
Diagnosis is clinical and testing is not usually needed unless bloody diarrhea, fever, or abdominal pain is present.
Treatment is fluid replacement and usually an antimotility drug such as loperamide; however, antimotility drugs are contraindicated in patients with fever or bloody stools and in children < 2 years of age.
Patients with more severe traveler's diarrhea are given antibiotics—a fluoroquinolone for adults and azithromycin for children.
Prevention is the best measure and involves careful selection of foods and beverages; prophylactic antibiotics are not routinely used except for immunocompromised patients.
The following are English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Centers for Disease Control and Prevention: Preparing international travelers for travelers’ diarrhea