What is the best treatment for a 13-year-old with a gastrointestinal (GI) bug?

Treatment of Gastroenteritis in a 13-Year-Old

The cornerstone of treatment for a 13-year-old with gastroenteritis is oral rehydration therapy (ORS) with early resumption of a normal diet, while avoiding antimotility drugs like loperamide, which are contraindicated in all children under 18 years of age. 1

Immediate Assessment and Hydration Strategy

Evaluate hydration status first by examining for decreased skin turgor, dry mucous membranes, sunken eyes, and altered mental status—these physical findings are more reliable than laboratory tests for determining dehydration severity. 1, 2

Rehydration Protocol

• For mild to moderate dehydration: Administer 50-100 mL/kg of reduced osmolarity ORS over 3-4 hours 2
• If vomiting is present: Give small, frequent volumes (5-10 mL) every 1-2 minutes, gradually increasing as tolerated 2
• For severe dehydration: Use intravenous rehydration until pulse, perfusion, and mental status normalize, then transition to ORS 1

Dietary Management

Resume a normal, age-appropriate diet immediately after rehydration is complete or even during the rehydration process. 1, 2 This approach decreases intestinal permeability, reduces illness duration, and improves nutritional outcomes. 1

Recommended Foods

• Starches: rice, potatoes, noodles, crackers, bananas 1
• Cereals: rice, wheat, oat cereals 1
• Soup, yogurt, vegetables, fresh fruits 1

Foods to Avoid

• High simple sugar content: soft drinks, undiluted apple juice, presweetened cereals (these worsen diarrhea through osmotic effects) 1
• High-fat foods (may delay gastric emptying) 1

Pharmacological Interventions

Antiemetics

Ondansetron may be given to facilitate oral rehydration tolerance in children over 4 years of age with significant vomiting. 1, 2 This can reduce immediate hospitalization needs and improve success of oral rehydration, though it may slightly increase stool volume. 1

Critical Contraindication: Antimotility Agents

Loperamide and other antimotility drugs are absolutely contraindicated in all children under 18 years of age with acute diarrhea. 1, 3 The FDA drug label explicitly states loperamide is contraindicated in pediatric patients less than 2 years due to respiratory depression and cardiac risks, and the IDSA guidelines extend this prohibition to all children under 18. 1, 3 Deaths have been reported in children given loperamide, with adverse events including ileus, abdominal distension, and lethargy. 1

Probiotics

Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent children. 1, 2 The evidence shows moderate quality support for this intervention. 1

When Antibiotics Are NOT Needed

Most cases of gastroenteritis in a 13-year-old are viral and do not require antibiotics. 1 Watery diarrhea with vomiting in an adolescent most likely represents viral gastroenteritis. 1

Empiric Antibiotics Are Indicated Only For:

• Bloody diarrhea with fever, severe abdominal pain, and signs of bacillary dysentery (frequent scant bloody stools, fever, cramps, tenesmus) 1
• Recent international travel with fever ≥38.5°C or signs of sepsis 1
• Immunocompromised patients with severe illness 1

If empiric treatment is needed, use azithromycin or a third-generation cephalosporin, depending on local susceptibility patterns and travel history. 1

Red Flags Requiring Medical Evaluation

Seek immediate medical attention for: 2

• Inability to tolerate oral fluids despite ondansetron
• Worsening signs of dehydration (decreased urine output, altered mental status)
• Development of bloody diarrhea
• High fever or signs of sepsis
• Symptoms persisting beyond 7-10 days

Prevention Measures

Hand hygiene is critical: Wash hands after using the toilet, before eating, and after handling garbage or touching animals. 1 Alcohol-based sanitizers or soap and water should be used based on the suspected pathogen. 1

Common Pitfalls to Avoid

• Never use loperamide or other antimotility agents in any child under 18 1, 3
• Do not withhold food for 24 hours—this outdated practice has no supporting evidence 1
• Avoid prolonged use of restrictive diets like BRAT—while reasonable initially, extended use results in inadequate energy and protein 1
• Do not routinely prescribe antibiotics—viral causes predominate and antibiotics shift focus away from appropriate fluid and nutritional therapy 1
• Avoid antimotility drugs in any patient with fever, bloody diarrhea, or suspected inflammatory diarrhea due to toxic megacolon risk 1, 2