What is the recommended treatment for a patient with gastroenteritis?

Treatment of Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for gastroenteritis in patients with mild to moderate dehydration, with intravenous fluids reserved only for severe dehydration, shock, altered mental status, or failure of oral rehydration. 1

Initial Assessment and Rehydration Strategy

Assess Dehydration Severity

Categorize dehydration based on clinical signs to guide treatment intensity 1:

• Mild dehydration (3-5% fluid deficit): Slightly dry mucous membranes, normal vital signs, good skin turgor 1
• Moderate dehydration (6-9% fluid deficit): Dry mucous membranes, loss of skin turgor with tenting, decreased urine output, possible tachycardia 1
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting (>2 seconds), cool extremities with poor perfusion, rapid deep breathing indicating acidosis 1

Oral Rehydration Protocol

For mild to moderate dehydration, administer low-osmolarity ORS at 50-100 mL/kg over 2-4 hours. 1 This successfully rehydrates >90% of patients without requiring intravenous therapy 2, 3.

Key technique for vomiting patients: Start with small volumes (5-10 mL every 1-2 minutes) using a spoon or syringe, gradually increasing as tolerated 1. This prevents triggering additional vomiting and allows successful oral rehydration even in patients with persistent emesis 1.

Replace ongoing losses continuously: 1

• 10 mL/kg ORS after each watery stool
• 2 mL/kg ORS after each vomiting episode

Nasogastric administration may be considered for patients who cannot tolerate oral intake or refuse to drink adequately 1.

Intravenous Rehydration

Reserve IV fluids for: 1

• Severe dehydration (≥10% fluid deficit)
• Hemodynamic instability or shock
• Altered mental status
• Failure of oral rehydration after appropriate trial
• Ileus (absent bowel sounds)

Administer isotonic crystalloid (lactated Ringer's or normal saline) in 20 mL/kg boluses until pulse, perfusion, and mental status normalize 1. Transition to ORS once the patient improves to replace remaining deficit 1.

Nutritional Management

Resume age-appropriate diet immediately during or after rehydration is completed. 1 Early refeeding reduces severity and duration of illness compared to fasting or restrictive diets 1.

Continue breastfeeding throughout the diarrheal episode in infants 1.

Avoid these foods during active illness: 1

• Foods high in simple sugars (soft drinks, undiluted apple juice) - worsen diarrhea through osmotic effects
• Caffeinated beverages (coffee, tea, energy drinks) - stimulate intestinal motility and accelerate transit time
• High-fat foods
• Lactose-containing products if diarrhea is prolonged

Pharmacological Management

Antiemetics

Ondansetron may be given to children >4 years and adolescents to facilitate oral rehydration when vomiting is significant 1. This can decrease the need for IV fluids and hospitalization 4.

Antimotility Agents

Loperamide is absolutely contraindicated in children <18 years with acute diarrhea due to serious adverse events including ileus and deaths 1, 5.

For immunocompetent adults with acute watery diarrhea (non-bloody, no fever), loperamide may be used once adequately hydrated 1:

• Initial dose: 4 mg orally 5
• Maintenance: 2 mg after each unformed stool or every 4 hours 5
• Maximum: 16 mg/day 5

Never use loperamide in: 1, 5

• Bloody diarrhea
• High fever
• Inflammatory diarrhea
• Children under 18 years

Probiotics and Zinc

Probiotics may reduce symptom severity and duration in both adults and children 1.

Zinc supplementation (10-20 mg daily for 10-14 days) reduces diarrhea duration in children 6 months to 5 years of age in areas with high zinc deficiency prevalence or in malnourished children 1.

Antimicrobial Therapy

Antibiotics should NOT be routinely administered for acute gastroenteritis 2, 1. Most cases are viral and self-limited 2, 6.

Consider antimicrobial therapy only in specific situations: 1

• Bloody diarrhea with fever and systemic toxicity (possible Shigella, Salmonella, Campylobacter)
• Recent antibiotic use (test for Clostridioides difficile)
• Immunocompromised patients with severe illness
• Recent travel to developing countries with persistent symptoms
• Infants <3 months with suspected bacterial etiology

When indicated, empiric therapy: 1

• Adults: Fluoroquinolone (ciprofloxacin) or azithromycin
• Children: Third-generation cephalosporin or azithromycin

Avoid antibiotics for STEC O157 infections as they may increase risk of hemolytic uremic syndrome 1.

Infection Control Measures

Implement strict hand hygiene: 1

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

Use gloves and gowns when caring for patients with diarrhea 1.

Clean and disinfect contaminated surfaces promptly - note that many germicidal chemicals are ineffective against rotavirus, but detergents do inactivate it 2.

Isolate ill persons from well persons until at least 2 days after symptom resolution 1.

Critical Pitfalls to Avoid

Do not delay rehydration while awaiting diagnostic testing - initiate ORS immediately 1.

Do not use inappropriate fluids (apple juice, sports drinks, soft drinks) as primary rehydration solutions for moderate to severe dehydration 1. These have inappropriate osmolarity and can worsen osmotic diarrhea 1.

Do not restrict diet unnecessarily during or after rehydration 1. Early feeding improves outcomes 1.

Do not give antimotility agents to children or in cases of bloody diarrhea 1, 5.

Do not use metoclopramide - it has no role in gastroenteritis management and may worsen diarrhea by accelerating GI transit 1.

When to Seek Immediate Medical Care

Red flags requiring urgent evaluation: 1

• Severe dehydration signs (altered mental status, prolonged skin tenting, poor perfusion)
• Bloody stools with fever
• Persistent vomiting preventing any oral intake
• No improvement after 48 hours of appropriate ORS therapy
• Symptoms worsening or clinical deterioration
• Abdominal distension
• Absent bowel sounds (ileus)

Lower threshold for admission in: 1

• Elderly patients (≥65 years) - higher mortality risk
• Infants <3 months
• Immunocompromised patients
• Patients with significant comorbidities