What is the treatment for infectious gastroenteritis?

Treatment of Infectious Gastroenteritis

The cornerstone of infectious gastroenteritis treatment is oral rehydration therapy using reduced osmolarity oral rehydration solution (ORS), with antimicrobial therapy reserved only for specific pathogens and clinical scenarios. 1

Initial Assessment and Triage

• Evaluate for:
  • Signs of dehydration (dry mucous membranes, decreased tears, capillary refill time)
  • Fever, dizziness, abdominal pain/cramping
  • Stool frequency, volume, and composition (bloody vs. non-bloody)
  • Risk for sepsis or bowel obstruction
  • Recent travel history and immunocompromised status 1

Rehydration Therapy

Mild to Moderate Dehydration

• First-line treatment: Reduced osmolarity oral rehydration solution (ORS)
  • Composition: 75-90 mEq/L sodium, 20 mEq/L potassium, 65-80 mEq/L chloride, 10 mEq/L citrate, 75-111 mmol/L glucose 1
  • Drink 8-10 large glasses of clear liquids daily 1
  • Commercial products like Pedialyte are effective, though Gatorade may be used in adults (caution: may cause persistent hypokalemia) 2

Severe Dehydration

• Start with isotonic IV fluids (lactated Ringer's or normal saline) at 60-100 mL/kg over 2-4 hours
• Transition to ORS once pulse, perfusion, and mental status normalize 1
• For children who refuse oral rehydration or are vomiting, continuous nasogastric application is as effective as IV rehydration 3

Dietary Management

• Resume age-appropriate diet during or immediately after rehydration
• Offer food every 3-4 hours 1
• Implement dietary modifications:
  • Stop lactose-containing products (temporary lactose intolerance is common)
  • Avoid alcohol, high-osmolar supplements, spices, coffee
  • Reduce insoluble fiber intake
  • Consider low FODMAP diet for suspected functional diarrhea 1

Antimicrobial Therapy

Important: In most cases of acute watery diarrhea without recent international travel, empiric antimicrobial therapy is not recommended 1

Antimicrobial therapy is indicated for:

• Clostridioides difficile infections
• Travel-related diarrhea with severe symptoms
• Specific bacterial infections with severe symptoms
• Parasitic infections 4
• Immunocompromised patients 1

Pathogen-Specific Treatment

Pathogen	First-line Treatment	Alternative Treatment
Shigella	Azithromycin	TMP-SMX (if susceptible)
Campylobacter	Azithromycin	Erythromycin
Enterotoxigenic E. coli (ETEC)	TMP-SMX (if susceptible) or Azithromycin
Bacterial gastroenteritis	Third-generation cephalosporin or Azithromycin

Caution: Avoid antimicrobial therapy for STEC O157 and other Shiga toxin 2-producing STEC 1

Symptomatic Treatment

Antimotility Agents

• Adults: Loperamide may be used for non-bloody diarrhea after adequate hydration
  • Initial dose: 4 mg followed by 2 mg every 4 hours (max 16 mg/day) 1
• Children: Antimotility drugs should not be given to children <18 years 1
• Contraindications: Bloody diarrhea, fever, or suspected inflammatory diarrhea 1

Antiemetics

• Ondansetron may be given to facilitate oral rehydration in children >4 years and adolescents with vomiting 1

Adjunctive Therapies

• Probiotics may reduce symptom severity and duration in immunocompetent patients
• Oral zinc supplementation is beneficial for children 6 months to 5 years in areas with high prevalence of zinc deficiency 1

Severe Cases Management

• For severe diarrhea (grade 3-4):
  • Administer octreotide at 100-150 μg subcutaneously three times daily
  • Start IV fluids and antibiotics as needed
  • Complete stool workup, CBC, and electrolyte profile
  • Consider octreotide dose escalation up to 500 μg until diarrhea is controlled
  • Low doses of morphine concentrate may be used if diarrhea persists 1

Prevention and Follow-up

• Implement proper hand hygiene and infection control measures
• Rotavirus vaccination is recommended to prevent rotavirus gastroenteritis 1
• Seek medical attention if:
  • No improvement within 48 hours
  • Worsening symptoms
  • Development of warning signs (severe vomiting, persistent fever, abdominal distension, blood in stool) 1

Common Pitfalls to Avoid

1. Overuse of antibiotics: Most viral gastroenteritis cases resolve without antimicrobial therapy
2. Inappropriate use of antimotility agents: Avoid in children and in cases of bloody diarrhea
3. Underestimating dehydration: Careful assessment of hydration status is crucial
4. Unnecessary hospitalization: Oral rehydration is often as effective as IV rehydration and can be done at home in mild to moderate cases 5
5. Ignoring post-infectious complications: Approximately 9% of patients develop post-infectious IBS 4