Treatment of Diarrhea in the Emergency Department

Initial Assessment and Fluid Management

• The American College of Physicians recommends that the cornerstone of treating diarrhea in the ER is rehydration therapy, with oral rehydration solution (ORS) as first-line for mild-to-moderate dehydration and intravenous isotonic fluids reserved for severe dehydration, shock, or ORS failure 1, 2, 3
• The Infectious Diseases Society of America suggests that mild-to-moderate dehydration (6-9% fluid deficit) is characterized by decreased skin turgor, dry mucous membranes, sunken eyes, and decreased urine output 4
• The Centers for Disease Control and Prevention recommend that severe dehydration (≥10% fluid deficit) is characterized by altered mental status, shock, poor perfusion, and inability to tolerate oral intake 3, 4

First-Line Rehydration Strategy

• The World Health Organization recommends administering reduced osmolarity ORS (<250 mmol/L) at 100 mL/kg over 2-4 hours for mild-to-moderate dehydration 1, 4
• The American Academy of Pediatrics suggests that commercial formulations of ORS include Pedialyte, CeraLyte, or Enfalac Lytren 5
• The National Institute of Diabetes and Digestive and Kidney Diseases recommends against using apple juice, Gatorade, or soft drinks for rehydration 5

Replace Ongoing Losses

• The European Society for Pediatric Gastroenterology, Hepatology, and Nutrition recommends that children <10 kg receive 60-120 mL ORS per diarrheal stool (up to ~500 mL/day) 4
• The American College of Gastroenterology suggests that children >10 kg receive 120-240 mL ORS per diarrheal stool (up to ~1 L/day) 4
• The Infectious Diseases Society of America recommends that adults receive ad libitum ORS, up to ~2 L/day 4

Antimicrobial Therapy

• The Centers for Disease Control and Prevention recommend that empiric antimicrobial therapy is not recommended in most cases of acute watery diarrhea without recent international travel 2, 3
• The World Health Organization suggests that exceptions where empiric antibiotics should be considered include immunocompromised patients with severe illness and bloody diarrhea, young infants who appear ill, and clinical features of sepsis with suspected enteric fever 2, 3, 6
• The National Institute of Allergy and Infectious Diseases recommends against using antibiotics in suspected STEC O157 or Shiga toxin 2-producing E. coli, as this increases the risk of hemolytic uremic syndrome 1, 6

Adjunctive Symptomatic Therapies

• The American College of Gastroenterology recommends that loperamide is contraindicated in all children <18 years of age, any patient with fever or bloody diarrhea, and suspected inflammatory diarrhea 1, 2, 3, 6
• The European Society for Pediatric Gastroenterology, Hepatology, and Nutrition suggests that loperamide may be given to immunocompetent adults with acute watery diarrhea only after adequate hydration 1, 2, 6
• The Infectious Diseases Society of America recommends that ondansetron may be given to children >4 years of age with vomiting to facilitate oral rehydration 1, 3, 4

Nutritional Management

• The World Health Organization recommends that breastfeeding should be continued throughout the diarrheal episode 1, 2, 3, 5, 6
• The American Academy of Pediatrics suggests that age-appropriate diet should be resumed during or immediately after rehydration 1, 2, 3, 5, 6
• The National Institute of Diabetes and Digestive and Kidney Diseases recommends that previously lactose-containing formula can be continued in most cases 5

Disposition Criteria

• The American College of Emergency Physicians recommends that patients can be discharged home if mild-to-moderate dehydration is successfully corrected with ORS, the patient tolerates oral intake, and reliable follow-up is available 4

Common Pitfalls to Avoid

• The Centers for Disease Control and Prevention recommend against withholding ORS in favor of IV fluids for mild-to-moderate dehydration, as ORS is equally effective and avoids IV complications 5
• The Infectious Diseases Society of America suggests that loperamide should not be given to children or patients with bloody/febrile diarrhea, due to the risk of toxic megacolon and serious cardiac events 1, 6
• The World Health Organization recommends against prescribing antibiotics empirically for simple watery diarrhea, as this increases resistance and may worsen STEC infections 2, 3
• The National Institute of Diabetes and Digestive and Kidney Diseases advises against using sports drinks or juice for rehydration, as incorrect osmolarity can worsen electrolyte imbalances 5

Management of Mild‑to‑Moderate Watery Diarrhea in Healthy Adults

Rehydration Strategy

• Reduced‑osmolarity oral rehydration solution (≤250 mmol/L) is the cornerstone of treatment for mild‑to‑moderate dehydration in otherwise healthy adults. 7
• Commercial reduced‑osmolarity ORS products (e.g., Pedialyte, CeraLyte, Enfalac Lytren) are appropriate choices. 8
• Apple juice, sports drinks (e.g., Gatorade), and soft drinks should be avoided for rehydration because their osmolarity is inappropriate and may worsen electrolyte balance. 8

When to Escalate to Intravenous Fluids

• Isotonic IV fluids (lactated Ringer’s or normal saline) are indicated if oral rehydration fails, the patient has ileus, or oral intake cannot be tolerated despite attempts. 9

Dietary Management

• Adults should resume their usual age‑appropriate diet during or immediately after rehydration; early feeding improves clinical outcomes. 7
• Withholding food or using diluted formulas provides no benefit and should be avoided. 8

Anti‑Motility Therapy (Loperamide)

• Loperamide may be administered to immunocompetent adults only after adequate hydration and in the absence of fever or bloody stools. 9
• Recommended dosing: 4 mg initial dose, then 2 mg every 2–4 hours or after each unformed stool, not to exceed 16 mg per day. 10
• Contraindications: presence of fever, bloody diarrhea, suspected toxic megacolon, or any concern for Shiga‑toxin‑producing E. coli (STEC) or other inflammatory diarrheas. [7][10]

Antibiotic Therapy

• Empiric antibiotics are not recommended for most adults with acute watery diarrhea who have not recently traveled internationally. 7
• Antibiotics can promote antimicrobial resistance and may exacerbate STEC infections, increasing the risk of hemolytic‑uremic syndrome. 7
• Antibiotics should be considered only in:
  
  • Immunocompromised patients with severe illness,
  • Patients with clinical sepsis and suspected enteric fever, or
  • Bloody diarrhea with fever suggesting an invasive bacterial pathogen. [7][10]
• Antibiotics must be avoided entirely when STEC O157 or Shiga‑toxin‑producing E. coli infection is suspected. 7

Adjunctive Therapies

• Ondansetron can be used to control vomiting and improve tolerance of oral rehydration in adults with significant nausea. 9
• Probiotic preparations may be offered to immunocompetent adults to modestly reduce symptom severity and duration. 9

Monitoring & Common Pitfalls

• ORS should not be withheld in favor of IV fluids for mild‑to‑moderate dehydration; ORS is equally effective and avoids IV‑related complications such as phlebitis and infection. 8
• Loperamide must not be given before confirming adequate hydration, as it can mask worsening dehydration. 9
• Routine empirical antibiotics for simple watery diarrhea should be avoided to prevent unnecessary resistance. 7
• Sports drinks or fruit juices are unsuitable for rehydration due to inappropriate osmolarity. 8
• Patients receiving ORS should be monitored frequently for signs of worsening dehydration (e.g., persistent tachycardia, poor perfusion, mental status changes) and reassessed promptly. 10