What is the treatment for gastroenteritis?

Treatment of Gastroenteritis

The mainstay of treatment for gastroenteritis is oral rehydration therapy (ORT) using reduced osmolarity oral rehydration solution (ORS), which should be the first-line therapy for mild to moderate dehydration in patients of all ages. 1

Rehydration Therapy Based on Dehydration Severity

Mild to Moderate Dehydration

• Oral rehydration solution (ORS) is the first-line treatment 1:
  • Infants and children: 50-100 mL/kg over 3-4 hours
  • Adolescents and adults (≥30 kg): 2-4 L
• Nasogastric administration of ORS may be considered for patients who cannot tolerate oral intake or refuse to drink adequately 1
• Commercial ORS formulations include Pedialyte, CeraLyte, and Enfalac Lytren 1
• Popular beverages like apple juice, Gatorade, and commercial soft drinks should NOT be used for rehydration 1

Severe Dehydration

• Intravenous isotonic fluids (lactated Ringer's or normal saline) should be administered when there is severe dehydration, shock, altered mental status, or failure of ORT 1
• For children, adolescents, and adults: IV boluses per fluid resuscitation guidelines until pulse, perfusion, and mental status normalize 1
• Once the patient is stabilized, transition to oral rehydration to complete rehydration 1

Ongoing Fluid Replacement

• For ongoing losses during maintenance phase 1:
  • Infants <10 kg: 60-120 mL ORS for each diarrheal stool/vomiting episode (up to ~500 mL/day)
  • Children >10 kg: 120-240 mL ORS for each diarrheal stool/vomiting episode (up to ~1 L/day)
  • Adolescents and adults: Ad libitum, up to ~2 L/day

Nutritional Management

• Early refeeding is recommended once rehydration is complete 1
• Breastfed infants should continue nursing throughout the illness 1
• Age-appropriate normal diet should be offered every 3-4 hours 1
• Diluted formula does not appear to confer any benefit 1
• Although commonly recommended, the BRAT (bananas, rice, applesauce, and toast) diet has limited supporting evidence 1
• Instructing patients to refrain from eating solid food for 24 hours is not useful 1
• A lactose-free diet may reduce the duration of diarrhea by an average of 18 hours in children under 5 years 1

Pharmacological Management

Antiemetics

• Ondansetron may be given to facilitate tolerance of oral rehydration in children >4 years and adolescents with vomiting 1, 2
• Antiemetics should only be considered once the patient is adequately hydrated 1
• Ondansetron can reduce the need for hospitalization and IV rehydration but may increase stool volume 1, 3

Antimotility Agents

• Loperamide may be given to immunocompetent adults with acute watery diarrhea 1, 4
• Loperamide should NOT be given to children <18 years of age with acute diarrhea 1, 4
• Loperamide should be avoided in patients with fever or inflammatory diarrhea due to risk of toxic megacolon 1, 4
• Cardiac adverse reactions, including QT prolongation and Torsades de Pointes, have been reported with higher than recommended doses of loperamide 4

Special Considerations

Children

• Children are more susceptible to dehydration due to higher body surface-to-weight ratio, higher metabolic rate, and dependence on others for fluid 1
• Signs of dehydration may be masked when a child is hypernatremic 1
• Antimotility drugs should be avoided in children due to risk of serious adverse events 1, 4

Elderly

• Maintenance of good hydration is particularly important in elderly patients, especially those receiving diuretic medication 1
• Elderly patients may be more susceptible to drug-associated effects on the QT interval, so caution is needed with medications like loperamide 4

Common Pitfalls to Avoid

• Using sports drinks or sodas for rehydration instead of proper ORS 1
• Delaying refeeding during acute gastroenteritis 1
• Using antimotility agents in children or in patients with inflammatory or bloody diarrhea 1, 4
• Overreliance on antiemetics and antimotility agents instead of proper fluid and electrolyte therapy 1
• Failing to recognize signs of severe dehydration requiring IV rehydration 1

Treatment Algorithm

1. Assess degree of dehydration
2. For mild-moderate dehydration: Start ORS
3. For severe dehydration: Start IV fluids until stabilized, then transition to ORS
4. Continue normal feeding as tolerated
5. Consider antiemetics only if vomiting prevents adequate oral rehydration
6. In adults only, consider antimotility agents for watery diarrhea without fever or blood
7. Monitor for response to therapy and adjust as needed