Management of Diarrhea
The cornerstone of diarrhea management is appropriate rehydration therapy, with oral rehydration solution being first-line for most cases and intravenous fluids reserved for severe dehydration or inability to tolerate oral intake. 1
Initial Assessment
Clinical Evaluation
- Determine duration of symptoms:
- Acute: 0-13 days
- Persistent: 14-29 days
- Chronic: ≥30 days 2
Key History Elements
- Stool characteristics (watery, bloody, mucous, greasy)
- Frequency and volume of bowel movements
- Presence of fever, abdominal pain, or tenesmus
- Symptoms of dehydration (thirst, decreased urination, lethargy)
- Recent medications (antibiotics, antacids, anti-motility agents)
- Travel history, food consumption, similar illness in contacts 2
Risk Factors for Complications
- Extremes of age (very young, elderly)
- Immunocompromised status
- Bloody diarrhea
- Severe abdominal pain
- Signs of dehydration
- Fever >38.5°C 2, 1
Assessment of Dehydration
- Mild dehydration (<3% weight loss): Minimal symptoms, slightly dry mucous membranes
- Moderate dehydration (3-9% weight loss): Decreased skin turgor, dry mucous membranes, tachycardia
- Severe dehydration (>9% weight loss): Altered mental status, poor perfusion, hypotension 1
Management Algorithm
1. Rehydration (Priority)
Mild to Moderate Dehydration
- Oral rehydration solution (ORS) containing 65-70 mEq/L sodium and 75-90 mmol/L glucose
- Target fluid intake: 2200-4000 mL/day 1
- Commercial solutions (Ceralyte, Pedialyte) or WHO formula:
- 3.5g NaCl + 2.5g NaHCO₃ + 1.5g KCl + 20g glucose per liter of clean water 2
Severe Dehydration
- Immediate IV fluid resuscitation with isotonic saline
- Initial bolus of 20 mL/kg, reassess and repeat if needed
- Monitor electrolytes, particularly sodium and potassium 1
- Continue until clinical signs of hypovolemia improve (target urine output >0.5 mL/kg/h) 1
2. Diet Recommendations
- Continue normal feeding during mild diarrhea
- Resume age-appropriate diet immediately after initial rehydration (within 4-6 hours)
- Avoid foods high in simple sugars and fats
- Continue breastfeeding throughout illness if applicable 1
3. Pharmacologic Management
Antimotility Agents
- Loperamide: Initial dose 4 mg followed by 2 mg after each loose stool (maximum 16 mg/day) 1, 3
- Contraindications: Bloody diarrhea, suspected inflammatory diarrhea, children <2 years, ileus 3
- Warning: Risk of cardiac adverse reactions (QT prolongation, Torsades de Pointes) with higher than recommended doses 3
For Severe, Refractory Diarrhea
4. Antibiotic Therapy
Antibiotics are indicated for:
- Immunocompromised patients
- Severe bloody diarrhea with fever
- Confirmed bacterial pathogens requiring treatment 2, 1
Recommended regimens:
- Shigella: Azithromycin (first-line) or TMP-SMX if susceptible
- Campylobacter: Azithromycin or erythromycin
- ETEC: TMP-SMX (if susceptible) or azithromycin 1
Important: Avoid antibiotics for E. coli O157:H7 or other Shiga toxin-producing E. coli as they may increase risk of hemolytic uremic syndrome 1
Special Considerations
When to Obtain Stool Studies
- Bloody diarrhea
- Severe abdominal pain
- Persistent fever
- Immunocompromised status
- Recent antibiotic use (consider C. difficile)
- Symptoms lasting >7 days 2
Warning Signs Requiring Immediate Medical Attention
- Persistent vomiting preventing ORS intake
- High stool output (>10 mL/kg/hour)
- Worsening dehydration despite treatment
- Lethargy or altered mental status 1
Chronic Diarrhea (≥30 days)
- Consider non-infectious causes (IBD, celiac disease, malabsorption)
- Evaluate for post-infectious IBS
- More extensive workup may be needed including endoscopy, imaging, and specialized testing 4
Prevention
- Hand hygiene after toilet use, before food preparation
- Safe food handling practices
- Access to clean water
- Appropriate infection control measures when caring for patients with diarrhea 1
Most cases of acute diarrhea are self-limiting viral infections that resolve with supportive care, but prompt recognition of severe cases requiring more aggressive management is essential to prevent morbidity and mortality.