What is the treatment for acute gastroenteritis?

Treatment of Acute Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for mild to moderate dehydration in acute gastroenteritis, with intravenous fluids reserved only for severe dehydration or ORS failure. 1

Initial Assessment of Dehydration Status

Evaluate hydration through specific physical examination findings: 1

• Decreased skin turgor
• Dry mucous membranes
• Sunken eyes
• Altered mental status
• Tachycardia
• Decreased urine output

Categorize dehydration severity based on clinical presentation: 1

• Mild: <4% body weight lost
• Moderate: 4-6% body weight lost
• Severe: >6% body weight lost

The most useful predictors of ≥5% dehydration are abnormal capillary refill, abnormal skin turgor, and abnormal respiratory pattern. 2

Oral Rehydration Therapy (First-Line Treatment)

Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte) as the primary rehydration solution. 1 Do not use apple juice, Gatorade, or commercial soft drinks—these are inappropriate for rehydration and can worsen diarrhea through osmotic effects. 1, 3

Dosing for Oral Rehydration:

Initial rehydration phase (first 3-4 hours): 1

• Infants and children: 50-100 mL/kg over 3-4 hours
• Adolescents and adults: 2-4 L of ORS over 3-4 hours

Replacement of ongoing losses (until symptoms resolve): 1

• Children <10 kg: 60-120 mL ORS after each diarrheal stool/vomiting episode (up to ~500 mL/day)
• Children >10 kg: 120-240 mL ORS after each diarrheal stool/vomiting episode (up to ~1 L/day)
• Adolescents and adults: Ad libitum intake up to ~2 L/day

Alternative Route if Oral Intake Fails:

If the child refuses ORS, consider nasogastric administration at 50-100 mL/kg over 3-4 hours. 1 This approach is as effective as intravenous therapy for mild to moderate dehydration. 4

Intravenous Rehydration (Severe Dehydration Only)

Reserve IV fluids for: 3

• Severe dehydration (>6% body weight lost)
• Shock or altered mental status
• Failure of oral rehydration therapy
• Ileus

Administer isotonic IV fluids (lactated Ringer's or normal saline) at 20 mL/kg over 30 minutes. 1 Continue IV rehydration for 2-4 hours until pulse, perfusion, and mental status normalize, then transition to ORS to replace remaining deficit. 1, 3

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration—do not withhold food for 24 hours. 1 Fasting does not improve outcomes and is contraindicated. 1

Continue breastfeeding throughout the diarrheal episode in infants. 1, 3 Early refeeding is recommended rather than restrictive diets. 3

Avoid foods high in simple sugars (soft drinks, undiluted apple juice) as they exacerbate diarrhea through osmotic effects. 3

Pharmacological Management

Antiemetics (To Facilitate Oral Rehydration):

Ondansetron (0.15 mg/kg per dose) may be given to children >4 years and adolescents with significant vomiting to facilitate oral rehydration. 1 Evidence shows ondansetron decreases vomiting, improves oral intake success, reduces need for IV fluids, and shortens emergency department stays with minimal side effects. 5, 2

Antimotility Agents:

Loperamide may be given to immunocompetent adults with acute watery diarrhea: 4 mg initially, followed by 2 mg after each loose stool. 1, 6

Critical contraindications for loperamide: 1, 3

• Never use in children <18 years
• Never use in inflammatory diarrhea (bloody stools)
• Never use with fever
• Never use if toxic megacolon suspected

The FDA label warns of cardiac adverse reactions including QT prolongation, Torsades de Pointes, and death with loperamide, particularly at higher than recommended doses or with CYP3A4/CYP2C8/P-glycoprotein inhibitors. 6 Monitor patients taking Class IA or III antiarrhythmics, antipsychotics, or other QT-prolonging drugs. 6

Antimicrobials:

Antimicrobial agents have limited usefulness since viral agents cause the majority of acute gastroenteritis. 3 Consider antibiotics only in specific cases: bloody diarrhea, recent antibiotic use, specific pathogen exposure, recent foreign travel, or immunodeficiency. 3

Other Agents:

Adsorbents, antisecretory drugs, and toxin binders should not be used as they do not reduce diarrhea volume or duration. 3

Infection Control Measures

Practice proper hand hygiene: 1, 3

• After using toilet or changing diapers
• Before and after food preparation
• Before eating
• After handling soiled items or animals

Use gloves and gowns when caring for patients with diarrhea. 1, 3 Clean and disinfect contaminated surfaces promptly, and separate ill persons from well persons until at least 2 days after symptom resolution. 3

Common Pitfalls to Avoid

Do not delay rehydration while awaiting diagnostic testing—initiate rehydration promptly. 3 The primary therapeutic focus must be on appropriate fluid, electrolyte, and nutritional therapy, not antidiarrheal agents. 3

Do not use inappropriate fluids (apple juice, sports drinks) as primary rehydration solutions for moderate to severe dehydration. 3 ORS is described as an "underused simple solution" despite proven efficacy equal to IV therapy. 5, 4

Do not unnecessarily restrict diet during or after rehydration. 3 Early feeding improves outcomes.

If clinical improvement is not observed within 48 hours, discontinue loperamide and contact a healthcare provider. 6 Seek immediate care for blood in stools, fever, or abdominal distention. 6