Diarrhea, Traveler's

Essentials of Diagnosis

• Usually a benign, self-limited disease occurring about a week into travel

• Prophylaxis not recommended unless there is a comorbid disease (inflammatory bowel syndrome, HIV, immunosuppressive medication)

• Single-dose therapy with a fluoroquinolone usually effective if symptoms develop

General Considerations

• Whenever a person travels from one country to another—particularly if the change involves a marked difference in climate, social conditions, or sanitation standards and facilities—diarrhea may develop within 2–10 days

• Bacteria cause 80% of cases

• Contributory causes include

  • Unusual food and drink

  • Change in living habits

  • Occasional viral infections (adenoviruses or rotaviruses)

  • Change in bowel flora

• Traveler's diarrhea is a risk factor for development of irritable bowel syndrome

Etiology

• Most common

  • Enterotoxigenic E coli

  • Shigella

  • Campylobacter

• Less common

  • Aeromonas

  • Salmonella

  • Noncholera vibrios

  • E histolytica

  • G lamblia

  • Adenoviruses

  • Rotavirus

• Chronic watery diarrhea

  • E histolytica

  • G lamblia

  • Tropical sprue (rare)

Symptoms and Signs

• There may be up to 10 or more loose stools per day

• Abdominal cramps, nausea, occasionally vomiting

• Fever is rare

• When cause is enterotoxigenic E coli

  • Stools are usually watery

  • Fever is not usually present

• When cause is invasive bacterial pathogens (eg, Shigella, Campylobacter, Salmonella)

  • Stools may be bloody

  • Fever may be present

• Course of illness

  • It usually subsides spontaneously within 1–5 days

  • However, 10% remain symptomatic for a week or longer

  • In 2%, symptoms persist for longer than a month

Laboratory Tests

• In patients with fever and bloody diarrhea, stool culture is indicated, but in most cases cultures are reserved for those who do not respond to antibiotics

Medications

• For most patients, symptomatic therapy with loperamide is all that is required provided there is no systemic illness (fever ≥ 39°C) or dysentery (bloody stools), in which case antimotility agents should be avoided

• Packages of oral rehydration salts to treat dehydration are available over the counter in the United States (Infalyte, Pedialyte, others) and in many foreign countries

• Loperamide (4 mg loading dose, then 2 mg after each loose stool to a maximum of 16 mg/day) with a single oral dose of ciprofloxacin (750 mg), levofloxacin (500 mg), or ofloxacin (200 mg) cures most cases

• If diarrhea is severe, associated with fever or bloody stools, or persists despite single-dose of a fluoroquinolone, then 1000 mg of azithromycin should be given

• Azithromycin is drug of choice for pregnant women and for cases due to invasive bacteria

• Rifaximin, a nonabsorbable rifampin-like drug, is effective at 200 mg orally three times daily or 400 mg orally twice daily for 3 days. Because the drug is not systemically absorbed, it should not be used in situations where there is a high likelihood of invasive disease (eg, fever, systemic toxicity, bloody stools)

Prognosis

• Most illnesses are short-lived and resolve without specific therapy

Prevention

• Recommend avoidance of fresh foods and water sources in developing countries, where infectious diarrheal illnesses are endemic

• Prophylaxis is recommended for

  • Patients with significant underlying disease (inflammatory bowel disease, HIV/AIDS, diabetes mellitus, heart disease in the elderly, conditions requiring immunosuppressive medications)

  • Patients whose full activity status during the trip is so essential that even short periods of diarrhea would be unacceptable

• Prophylaxis is started upon entry into the destination country and is continued for 1 or 2 days after leaving

• For stays of more than 3 weeks, prophylaxis is not recommended because of the cost and increased toxicity

• Numerous antimicrobial regimens for once-daily oral prophylaxis are effective, such as

  • Ciprofloxacin, 500 mg

  • Rifaximin, 200 mg

• Bismuth subsalicylate

  • Effective, but rarely used

  • Turns the tongue and the stools black

  • Can interfere with doxycycline absorption, which may be needed for malaria prophylaxis

• Because not all travelers will have diarrhea and because most episodes are brief and self-limited, an alternative approach currently recommended is to provide the traveler with a supply of antimicrobials

When to Refer

• Cases refractory to treatment

• Persistent infection

• Immunocompromised patient

When to Admit

• Severe dehydration

• Hemodynamically unstable