Treatment of Acute Gastroenteritis

Assessment and Rehydration

The American College of Physicians and the Infectious Diseases Society of America recommend oral rehydration therapy (ORT) as the first-line approach for mild to moderate dehydration in both children and adults, with a strength of evidence rated as high 1, 2
Evaluate hydration status through physical examination and look for specific signs of dehydration, including decreased skin turgor, dry mucous membranes, sunken eyes, altered mental status, tachycardia, and decreased urine output, as recommended by the Clinical Infectious Diseases society 2, 3
Categorize dehydration as mild, moderate, or severe based on clinical presentation, with mild dehydration characterized by fewer than 4% of body weight lost, moderate dehydration characterized by 4-6% of body weight lost, and severe dehydration characterized by more than 6% of body weight lost 2

Provide oral rehydration solution (ORS) as first-line therapy for mild to moderate dehydration, with a recommended dose of 50-100 mL/kg over 3-4 hours for infants and children, and 2-4 L of ORS for adolescents and adults, as recommended by the World Health Organization and the American Academy of Pediatrics 2, 3
Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte) and avoid apple juice, Gatorade, and commercial soft drinks as they are not appropriate for rehydration, with a strength of evidence rated as high 3
For children who refuse ORS, nasogastric administration may be considered, with a recommended dose of 50-100 mL/kg over 3-4 hours, as recommended by the American Academy of Pediatrics 1, 2

Administer isotonic intravenous fluids (lactated Ringer's or normal saline) for severe dehydration, with a recommended dose of 20 mL/kg over 30 minutes, as recommended by the American College of Emergency Physicians and the Infectious Diseases Society of America 1, 4
Continue IV rehydration until pulse, perfusion, and mental status normalize, with a recommended duration of 2-4 hours, as recommended by the American College of Emergency Physicians and the Infectious Diseases Society of America 4

Replace ongoing losses with ORS until diarrhea and vomiting resolve, with a recommended dose of 60-120 mL ORS for each diarrheal stool/vomiting episode (up to ~500 mL/day) for children <10 kg, and 120-240 mL ORS for each diarrheal stool/vomiting episode (up to ~1 L/day) for children >10 kg, as recommended by the World Health Organization and the American Academy of Pediatrics 1, 2
For adolescents and adults, recommend ad libitum intake up to ~2 L/day, as recommended by the American College of Physicians and the Infectious Diseases Society of America 2

Continue breastfeeding throughout the diarrheal episode in infants, as recommended by the World Health Organization and the American Academy of Pediatrics 1, 4
Resume age-appropriate diet during or immediately after rehydration, as recommended by the American Academy of Pediatrics and the Infectious Diseases Society of America 1, 4
Avoid fasting or withholding food for 24 hours as this does not improve outcomes, with a strength of evidence rated as high 5

Consider ondansetron in children >4 years and adolescents with significant vomiting to facilitate oral rehydration, with a recommended dose of 0.15 mg/kg per dose, as recommended by the American Academy of Pediatrics and the Infectious Diseases Society of America 7
Loperamide may be given to immunocompetent adults with acute watery diarrhea, with a recommended dose of 4 mg initially, followed by 2 mg after each loose stool, as recommended by the American College of Physicians and the Infectious Diseases Society of America 7, 8
Avoid antimotility agents in cases of inflammatory diarrhea, diarrhea with fever, or suspected toxic megacolon, with a strength of evidence rated as high 7

Practice proper hand hygiene after using toilet, changing diapers, before/after food preparation, and after handling animals, as recommended by the Centers for Disease Control and Prevention and the World Health Organization 1
Use infection control measures including gloves, gowns, and hand hygiene with soap and water or alcohol-based sanitizers when caring for patients with diarrhea, as recommended by the Centers for Disease Control and Prevention and the World Health Organization 1