Acute Gastroenteritis Diagnosis and Management

Clinical Presentation and Diagnosis

The American College of Physicians and the Infectious Diseases Society of America recommend considering norovirus as the primary diagnosis for acute viral gastroenteritis, characterized by violent vomiting and nonbloody diarrhea lasting 2-3 days or less, with associated headache and body aches 1
Low-grade fever is present in approximately 40% of norovirus infections during the first 24 hours, according to the Centers for Disease Control and Prevention 1
The presence of fever, headache, and body aches in travelers should prompt consideration of enteric fever (typhoid/paratyphoid), although diarrhea is uncommon in enteric fever 2

Bacterial gastroenteritis (Salmonella, Shigella, Campylobacter) is less likely due to the absence of fever and bloody stools, as stated by the World Health Organization 1
Giardia lamblia is the most common parasitic cause of diarrhea in travelers, and evaluation for this should occur if diarrhea persists beyond 14 days, according to the Centers for Disease Control and Prevention 3

The Infectious Diseases Society of America recommends against pursuing stool testing in uncomplicated traveler's diarrhea, as most cases are self-limited and do not require testing 1
Stool testing should be pursued if diarrhea persists ≥14 days, fever develops or persists, bloody stools appear, or severe dehydration occurs, as recommended by the American College of Physicians 1
Supportive care, including oral rehydration therapy and resuming a normal diet as tolerated, is the mainstay of treatment, according to the World Health Organization 4

Signs of severe dehydration, such as altered mental status, decreased urine output, and orthostatic hypotension, require immediate evaluation, as stated by the American Heart Association 2
High fever (>38.5°C) persisting beyond 24-48 hours, bloody stools, and severe abdominal pain are red flags that require prompt attention, according to the Centers for Disease Control and Prevention 5

The majority of traveler's diarrhea is bacterial and lasts less than 7 days, but domestic travel (not internationally to a developing country) makes bacterial causes less probable in patients with acute diarrhea 6
Parasitic infections like Giardia typically cause persistent diarrhea lasting weeks to months, not 5 days, and evaluation for parasites should only be considered if diarrhea persists ≥14 days 6
In immunosuppressed patients, pursue stool testing if diarrhea persists, bloody stools appear, high fever persists, severe dehydration develops, or if the patient is immunosuppressed 6

No specific management approach facts with citations were found, however, the following fact from the clinical presentation is relevant to management:
In patients with acute diarrhea, bacterial causes are less likely if the patient has domestic travel history and no bloody stools 6