What is the treatment for adults with gastroenteritis?

Treatment of Gastroenteritis in Adults

Oral rehydration solution (ORS) is the first-line treatment for adults with mild to moderate dehydration from gastroenteritis, with early refeeding and supportive care forming the cornerstone of management. 1, 2

Rehydration Strategy

Oral Rehydration Therapy

• Use reduced osmolarity ORS as primary treatment for mild to moderate dehydration rather than sports drinks, juices, or other beverages 1, 2
• Administer 100 mL/kg over 2-4 hours for moderate dehydration (6-9% fluid deficit) 2
• Replace ongoing losses: 10 mL/kg ORS for each watery stool and 2 mL/kg for each vomiting episode 2
• Continue ORS until clinical dehydration resolves and to replace ongoing losses until symptoms cease 2
• Avoid high-sugar beverages (soft drinks, undiluted apple juice) as they worsen diarrhea through osmotic effects 2

Intravenous Rehydration

• Reserve IV fluids for severe dehydration (≥10% deficit), shock, altered mental status, or failure of oral rehydration 2
• Use isotonic fluids (lactated Ringer's or normal saline) 2
• Transition to ORS once pulse, perfusion, and mental status normalize 2

Nutritional Management

• Resume normal age-appropriate diet immediately after rehydration rather than prolonged fasting or restrictive diets 2
• Early refeeding reduces symptom duration and improves outcomes 2

Pharmacological Management

Antimotility Agents

• Loperamide may be used in immunocompetent adults with acute watery diarrhea once adequately hydrated 2, 3
• FDA-approved for acute nonspecific diarrhea and chronic diarrhea associated with inflammatory bowel disease 3
• Do not use loperamide in bloody diarrhea or suspected bacterial dysentery due to risk of complications 2

Antiemetics

• Ondansetron may be given to facilitate oral rehydration when vomiting is significant 2
• Reduces hospitalization rates and improves ORS compliance 4

Probiotics

• May reduce symptom severity and duration in adults 2

Antimicrobials

• Empiric antibiotics are NOT recommended for most cases of acute watery diarrhea, as viral pathogens predominate 1, 2
• Consider empiric treatment only in specific circumstances (see below) 1

When to Consider Empiric Antibiotics

Bloody Diarrhea

Empiric antibiotics are generally NOT recommended for bloody diarrhea while awaiting test results, except in these specific situations 1:

• Ill patients with fever documented in medical setting, abdominal pain, bloody diarrhea, and bacillary dysentery (frequent scant bloody stools, fever, cramps, tenesmus) presumptively due to Shigella 1
• Recent international travel with temperature ≥38.5°C and/or signs of sepsis 1
• Immunocompromised patients with severe illness and bloody diarrhea 1

Antibiotic Choice

• First-line empiric therapy: fluoroquinolone (ciprofloxacin) or azithromycin, depending on local susceptibility patterns and travel history 1
• Modify or discontinue when pathogen identified 1

Critical Exception

• Avoid antimicrobials in STEC O157 and other STEC producing Shiga toxin 2 due to increased risk of hemolytic uremic syndrome 1

Agents to Avoid

• Do not use adsorbents, antisecretory drugs, or toxin binders as they lack demonstrated effectiveness 2
• Antimotility agents should not be used in children, bloody diarrhea, or suspected bacterial dysentery 2

Infection Control

• Practice rigorous hand hygiene after toilet use, before eating, and after handling soiled items 2
• Use gloves and gowns when caring for ill patients 2
• Clean and disinfect contaminated surfaces promptly 2
• Isolate ill persons until at least 2 days after symptom resolution 2

When to Reassess

• Reevaluate patients not responding to initial therapy for noninfectious conditions including lactose intolerance 1
• Consider inflammatory bowel disease or irritable bowel syndrome in patients with symptoms lasting ≥14 days without identified infectious source 1
• Reassess fluid/electrolyte balance, nutritional status, and antimicrobial therapy in persistent cases 1

Common Pitfalls to Avoid

• Delaying rehydration while awaiting diagnostic tests—start ORS immediately 2
• Using inappropriate fluids (sports drinks, juices) as primary rehydration for moderate-severe dehydration 2
• Unnecessarily restricting diet during or after rehydration 2
• Prescribing antibiotics for typical viral gastroenteritis 2
• Using antimotility agents in bloody diarrhea or children 2