What is the treatment for acute diarrhea?

Treatment of Acute Diarrhea

The cornerstone of acute diarrhea treatment is oral rehydration therapy (ORS) with appropriate fluid and electrolyte replacement, followed by early refeeding and nutritional management, regardless of the causative pathogen. 1, 2

Initial Assessment

Immediately assess dehydration severity by examining:

• Skin turgor (prolonged retraction indicates moderate-to-severe dehydration) 2
• Mucous membranes (dry indicates dehydration) 2
• Mental status (altered consciousness suggests severe dehydration) 2
• Pulse and capillary refill (rapid pulse and delayed refill indicate poor perfusion) 2
• Urine output (decreased output indicates dehydration) 2
• Body weight to establish baseline for monitoring 2

Categorize dehydration as:

• Mild: 3-5% fluid deficit 2
• Moderate: 6-9% fluid deficit 2, 3
• Severe: ≥10% fluid deficit 2

Rehydration Protocol

For Mild Dehydration

Administer 50 mL/kg of ORS containing 50-90 mEq/L sodium over 2-4 hours. 2

For Moderate Dehydration

Administer 100 mL/kg of ORS over 2-4 hours. 2, 3 Start with small volumes (one teaspoon) using a teaspoon, syringe, or medicine dropper, then gradually increase as tolerated. 3

For Severe Dehydration or Shock

Switch to intravenous isotonic fluids (lactated Ringer's or normal saline) immediately. 3 IV therapy is also indicated for altered mental status, ileus, or failure of oral rehydration. 4, 3

Critical caveat: Oral rehydration is contraindicated when ileus is present, as it can worsen abdominal distention. 4

Replacement of Ongoing Losses

Throughout both rehydration and maintenance phases, replace ongoing losses continuously: 2

• 10 mL/kg of ORS for each watery/loose stool 2
• 2 mL/kg of ORS for each vomiting episode 2

For infants <10 kg: provide 60-120 mL ORS per diarrheal stool or vomiting episode, up to ~500 mL/day. 3

For children <2 years: 50-100 mL after each stool. 3

For older children: 100-200 mL after each stool. 3

For adults: as much ORS as desired. 3

Dietary Management

Breastfed infants must continue nursing on demand throughout the illness. 2, 3 This is non-negotiable for maintaining nutrition and hydration.

Bottle-fed infants should receive full-strength, lactose-free or lactose-reduced formulas immediately upon rehydration. 2, 3

Children >4-6 months should be offered age-appropriate foods every 3-4 hours as tolerated. 3 Early refeeding is essential—do not withhold food.

Adults should resume food intake guided by appetite, avoiding fatty, heavy, spicy foods, caffeine, and lactose-containing foods in prolonged episodes. 2

Pharmacological Treatment

Antimotility Agents

Loperamide 2 mg is the drug of choice for adults with non-bloody diarrhea. 2 It reduces symptom duration and severity. 5, 6

Absolute contraindications to loperamide: 2, 7

• Bloody diarrhea (risk of toxic megacolon)
• High fever (suggests invasive pathogen)
• Children <2 years of age (risk of respiratory depression and serious cardiac adverse reactions)
• Ileus or suspected ileus (can cause paralytic ileus)
• Patients with AIDS and abdominal distention (risk of toxic megacolon)

Additional warnings: Avoid loperamide in combination with QT-prolonging drugs (Class IA/III antiarrhythmics, antipsychotics, certain antibiotics) and in patients with cardiac risk factors, as it can cause Torsades de Pointes, ventricular arrhythmias, and sudden death at higher-than-recommended doses. 7

Antibiotics

Reserve antibiotics for specific indications only—do not use empirically for routine acute diarrhea. 2 The vast majority of acute diarrhea is viral and self-limited. 1, 6

Specific indications for antibiotics: 2, 5

• Shigellosis (dysentery with bloody diarrhea)
• Cholera (severe watery diarrhea)
• Traveler's diarrhea (azithromycin 500 mg single dose for watery diarrhea; 1000 mg single dose for febrile/dysenteric diarrhea) 5
• Campylobacteriosis (azithromycin preferred due to fluoroquinolone resistance) 5
• Immunosuppressed patients 8

Azithromycin is now the preferred first-line antibiotic due to increasing fluoroquinolone resistance among Campylobacter species. 5

Special Populations

Pediatric Patients

Over 90% of vomiting children can be successfully rehydrated orally when small volumes are given every 1-2 minutes with gradual increases. 2 For intractable vomiting, consider continuous nasogastric ORS infusion at 15 mL/kg/hour. 2, 3

Loperamide is contraindicated in children <2 years due to risks of respiratory depression and cardiac adverse reactions. 7

Elderly Patients

Elderly patients require medical supervision rather than self-medication due to higher risk of rapid dehydration, electrolyte imbalances, renal decline, and malnutrition. 2 They are particularly vulnerable to complications.

Monitoring and Reassessment

Reassess hydration status after 2-4 hours of rehydration. 3 If still dehydrated, reestimate the fluid deficit and restart rehydration therapy. 3

Monitor:

• Weight changes throughout therapy 3
• Vital signs (pulse, perfusion, mental status) 4
• Stool frequency and consistency 3
• Return of bowel function (passage of flatus or stool if ileus was suspected) 4

Common Pitfalls to Avoid

Do not prescribe "clear liquids" (juices, sodas, sports drinks) instead of properly formulated ORS—these lack appropriate sodium and glucose concentrations for optimal absorption. 1

Do not withhold food during or after rehydration—early refeeding is essential for recovery. 2, 3

Do not use antimotility agents in bloody diarrhea, high fever, or suspected invasive pathogens—this can precipitate toxic megacolon. 2, 7

Do not routinely order stool cultures—reserve diagnostic testing for severe dehydration, persistent fever, bloody stool, immunosuppression, or suspected outbreak. 6