What is the treatment for gastroenteritis?

Treatment of Gastroenteritis

Oral rehydration solution (ORS) is the first-line treatment for gastroenteritis in both children and adults with mild to moderate dehydration, with intravenous fluids reserved only for severe dehydration or failure of oral therapy. 1, 2

Initial Assessment

Evaluate hydration status through specific clinical signs 1, 2:

• Skin turgor (decreased indicates dehydration)
• Mental status (altered with severe dehydration)
• Mucous membrane moisture (dry membranes suggest dehydration)
• Capillary refill time (prolonged >2 seconds indicates poor perfusion)
• Vital signs (tachycardia, hypotension in severe cases)
• Urine output (decreased or absent)
• Sunken eyes (particularly in children)

Categorize dehydration severity 1, 2:

• Mild: 3-5% body weight loss (or <4% in some classifications)
• Moderate: 6-9% body weight loss (or 4-6%)
• Severe: ≥10% body weight loss (or >6%)

Rehydration Strategy

Mild to Moderate Dehydration

Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte) as the primary rehydration fluid 2:

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

Do not use apple juice, sports drinks (Gatorade), or commercial soft drinks as primary rehydration solutions for moderate to severe dehydration, as these contain inappropriate electrolyte concentrations and high simple sugar content that can worsen diarrhea through osmotic effects 1, 2. Low-osmolarity ORS formulations are specifically preferred over sports drinks 1.

For children who refuse oral intake, nasogastric administration of ORS may be considered at 50-100 mL/kg over 3-4 hours 1, 2.

Severe Dehydration

Administer isotonic intravenous fluids (lactated Ringer's or normal saline) at 20 mL/kg over 30 minutes 2:

• Continue IV rehydration until pulse, perfusion, and mental status normalize (typically 2-4 hours) 2
• Transition to ORS to replace remaining deficit once the patient improves 1

Reserve IV therapy only for 1, 2:

• Severe dehydration or shock
• Altered mental status
• Failure of oral rehydration therapy
• Ileus
• Patient refusal or inability to tolerate oral intake

Ongoing Losses Replacement

Continue ORS to replace ongoing losses until diarrhea and vomiting resolve 1, 2:

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

Nutritional Management

Resume age-appropriate diet during or immediately after rehydration—do not fast or restrict diet 1, 2:

• Continue breastfeeding throughout the diarrheal episode in infants 1, 2
• Early refeeding improves outcomes compared to fasting or restrictive diets 1
• Avoid withholding food for 24 hours as this does not improve outcomes 2

Avoid foods high in simple sugars (soft drinks, undiluted apple juice) as they can exacerbate diarrhea through osmotic effects 1.

Pharmacological Management

Antiemetics

Ondansetron may be given to children >4 years and adolescents with significant vomiting to facilitate oral rehydration 1, 2:

• Dose: 0.15 mg/kg per dose 2
• This reduces vomiting, facilitates ORT, and decreases need for IV fluids and hospitalization 1, 3

Antimotility Agents

Loperamide is contraindicated in children <18 years with acute diarrhea 1, 4:

• The FDA warns of cardiac adverse reactions including QT prolongation, Torsades de Pointes, cardiac arrest, and death with higher-than-recommended doses 4
• Postmarketing cases of cardiac arrest, syncope, and respiratory depression have been reported in pediatric patients <2 years 4
• Loperamide is contraindicated in children <2 years of age 4

For immunocompetent adults with acute watery diarrhea, loperamide may be given once adequately hydrated 1, 2:

• Dose: 4 mg initially, followed by 2 mg after each loose stool 2
• Avoid in: inflammatory diarrhea, bloody diarrhea, fever, suspected toxic megacolon, or when inhibition of peristalsis should be avoided 2, 4
• Avoid in combination with drugs that prolong QT interval or in patients with cardiac risk factors 4

Probiotics

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

• Evidence is strongest for Lactobacillus rhamnosus GG, Lactobacillus reuteri, and Saccharomyces boulardii 5
• The benefit is statistically significant but clinically moderate (approximately 24-hour reduction in duration) 5
• Evidence is more convincing for viral gastroenteritis than bacterial or parasitic infections 5

Zinc Supplementation

Zinc supplementation reduces diarrhea duration in children 6 months to 5 years in areas with high zinc deficiency prevalence or in malnourished children 1.

Antimicrobials

Antimicrobial agents have limited usefulness since viral agents are the predominant cause 1:

• Consider antimicrobial therapy only in specific cases: bloody diarrhea, recent antibiotic use, exposure to certain pathogens (e.g., Shigella, Campylobacter), recent foreign travel, or immunodeficiency 1, 6
• Most cases of viral gastroenteritis are self-limited and do not require antibiotics 7

Agents to Avoid

Do not use adsorbents, antisecretory drugs, or toxin binders as they do not reduce diarrhea volume or duration 1. These agents shift therapeutic focus away from appropriate fluid, electrolyte, and nutritional therapy 1.

Infection Control Measures

Practice proper hand hygiene 1, 2:

• 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 people with diarrhea 1, 2.

Clean and disinfect contaminated surfaces promptly 1, 2:

• Detergents inactivate rotavirus and should be used for laundering fecally contaminated linens and clothing 7
• Thorough cleaning of environmental surfaces is required as a minimum to control spread 7

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

Critical Pitfalls to Avoid

• Do not delay rehydration therapy while awaiting diagnostic testing—initiate rehydration promptly 1
• Do not use inappropriate fluids (apple juice, sports drinks) as primary rehydration solutions for moderate to severe dehydration 1
• Do not administer antimotility drugs to children or in cases of bloody diarrhea 1, 2
• Do not unnecessarily restrict diet during or after rehydration 1, 2
• Do not neglect infection control measures as this can lead to outbreaks 1

Special Considerations

For malnourished patients, the cycle of diarrhea and malnutrition compounds the public health impact, with acute diarrhea converting marginal nutritional status into undernourishment 7.

For elderly patients and those on diuretic medication, maintenance of good hydration is particularly important 7.

The main risk in viral gastroenteritis is dehydration and electrolyte imbalance, as virus replication is restricted to the gut mucosa and the illness is self-limited in most humans 7.