First-Line Treatment for Gastroenteritis in Healthy Adults
Oral rehydration solution (ORS) is the first-line treatment for acute gastroenteritis in healthy adults without blood in stool or high fever. 1
Rehydration as Primary Therapy
Reduced osmolarity ORS should be administered immediately as the cornerstone of management for mild to moderate dehydration. 1 This recommendation carries strong evidence and applies universally to adults with acute watery diarrhea from any cause. 1
- Continue ORS administration until clinical dehydration is corrected, replacing ongoing losses (approximately 10 mL/kg for each watery stool) until diarrhea resolves. 1
- ORS is as effective as intravenous therapy for mild to moderate dehydration and should be prioritized over IV fluids in this setting. 2
- Reserve intravenous isotonic fluids (lactated Ringer's or normal saline) only for severe dehydration, shock, altered mental status, or failure of oral rehydration therapy. 1
Antimicrobial Therapy: Generally NOT Indicated
In healthy adults with acute watery diarrhea without recent international travel, empiric antimicrobial therapy is NOT recommended. 1 This is a strong recommendation based on the fact that most acute gastroenteritis is viral and self-limited. 3
- Antibiotics should be avoided unless the patient has bloody diarrhea with high fever (≥38.5°C) and signs of dysentery, or recent international travel with fever/sepsis. 1
- The absence of blood in stool and high fever in your scenario makes antimicrobial therapy inappropriate. 1
Dietary Management
Resume a normal, age-appropriate diet during or immediately after rehydration is completed. 1
- Early refeeding is recommended rather than fasting or restrictive diets. 4
- Avoid foods high in simple sugars (soft drinks, undiluted fruit juices), high-fat foods, and caffeinated beverages, as these can exacerbate diarrhea through osmotic effects and increased intestinal motility. 4
Adjunctive Symptomatic Therapy
Antimotility agents like loperamide may be used in immunocompetent adults with acute watery diarrhea once adequately hydrated, but are NOT a substitute for rehydration. 1
- Critical caveat: Loperamide should be avoided if there is any suspicion of inflammatory diarrhea, fever, or bloody stools, as it may precipitate toxic megacolon. 1
- Given your patient has no blood in stool or high fever, loperamide could be considered after adequate hydration, but rehydration remains the priority. 1
- Antiemetics (such as ondansetron) may facilitate tolerance of oral rehydration if significant nausea/vomiting is present. 1
What NOT to Do: Common Pitfalls
Do not use adsorbents, antisecretory drugs, or toxin binders—these agents do not reduce diarrhea volume or duration and are not recommended. 4
Do not delay rehydration while awaiting diagnostic testing. 4 In a healthy adult without alarm features (no blood, no high fever), stool studies are generally unnecessary. 3
Do not prescribe antibiotics empirically in this scenario. 1 Inappropriate antibiotic use contributes to resistance and provides no benefit in viral gastroenteritis, which accounts for approximately 70% of cases. 2