How to manage diarrhea?

Management of Diarrhea

Oral rehydration solution (ORS) is the cornerstone of diarrhea management for all ages and should be initiated immediately for any patient with mild to moderate dehydration, with reduced osmolarity formulations (50-90 mEq/L sodium) being first-line therapy. 1

Immediate Assessment

Assess dehydration severity through physical examination:

• Mild dehydration (3-5% fluid deficit): Increased thirst, slightly dry mucous membranes 2, 3
• Moderate dehydration (6-9% fluid deficit): Loss of skin turgor, dry mucous membranes, decreased urine output 2, 3
• Severe dehydration (≥10% fluid deficit): Severe lethargy or altered consciousness, prolonged skin tenting, shock 1, 3

Key physical findings include rapid deep breathing, prolonged capillary refill, and decreased perfusion—these are more reliable than sunken fontanelle or absent tears 3.

Rehydration Protocol

Mild to Moderate Dehydration

Administer reduced osmolarity ORS (50-90 mEq/L sodium) as first-line therapy for all patients regardless of age or diarrhea cause. 1

• Mild dehydration: Give 50 mL/kg ORS over 2-4 hours 2, 3
• Moderate dehydration: Give 100 mL/kg ORS over 2-4 hours 1, 2
• Administration technique: Give small volumes (5-10 mL) every 1-2 minutes via spoon or syringe, gradually increasing as tolerated 1, 2

For patients with vomiting, over 90% can still be successfully rehydrated orally using this small-volume technique 2. If oral intake fails, consider nasogastric ORS administration 1.

Severe Dehydration

This is a medical emergency requiring immediate intravenous rehydration. 1, 3

• Administer 20 mL/kg boluses of lactated Ringer's or normal saline until pulse, perfusion, and mental status normalize 1
• Continue IV fluids until the patient is alert, has no aspiration risk, and has no ileus 1
• Once stabilized, transition to ORS for remaining deficit replacement 1

Ongoing Loss Replacement

Replace ongoing stool and vomit losses continuously throughout treatment. 2

• Give 10 mL/kg ORS for each watery/loose stool 1, 2
• Give 2 mL/kg ORS for each vomiting episode 1, 2
• Continue replacement until diarrhea and vomiting resolve 1

Nutritional Management

Infants and Children

Continue breastfeeding on demand throughout the illness without interruption. 1

For bottle-fed infants, administer full-strength, lactose-free or lactose-reduced formulas immediately upon rehydration 1, 2. Most children tolerate their usual lactose-containing formula without issue 1. True lactose intolerance is indicated only by worsening diarrhea upon reintroduction, not by stool pH or reducing substances alone 1.

Resume age-appropriate usual diet during or immediately after rehydration is completed. 1

Older children should receive starches, cereals, yogurt, fruits, and vegetables while avoiding foods high in simple sugars and fats 1.

Adults

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

Pharmacological Treatment

Antimotility Agents

Loperamide 2 mg is the drug of choice for immunocompetent adults with acute watery diarrhea. 4

• Adult dosing: Initial 4 mg (two capsules), then 2 mg after each unformed stool, maximum 16 mg daily 4
• Contraindications: Children <2 years (risk of respiratory depression and cardiac adverse reactions), children <18 years with acute diarrhea, bloody diarrhea, high fever, or suspected inflammatory diarrhea (risk of toxic megacolon) 1, 4

Critical warning: Avoid loperamide in elderly patients taking QT-prolonging drugs (Class IA or III antiarrhythmics) due to cardiac risks 4.

Antiemetics

Ondansetron may be given to children >4 years and adolescents with vomiting to facilitate oral rehydration tolerance 1.

Probiotics

Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent adults and children with infectious or antimicrobial-associated diarrhea 1.

Zinc Supplementation

Oral zinc reduces diarrhea duration in children 6 months to 5 years in countries with high zinc deficiency prevalence or signs of malnutrition 1.

Antibiotic Therapy

Reserve antibiotics for specific indications only—they are not routinely indicated for acute diarrhea. 1, 2

Consider antibiotics when:

• Dysentery (bloody diarrhea) is present 1
• High fever persists 1
• Watery diarrhea lasts >5 days 1
• Stool studies identify a treatable pathogen (shigellosis, cholera, traveler's diarrhea, protozoal infections) 5

Modify or discontinue antimicrobial treatment when a clinically plausible organism is identified. 1

Special Populations

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

Avoid loperamide in elderly patients on QT-prolonging medications 4.

Patients with Intractable Vomiting

Administer ORS in 5-10 mL volumes every 1-2 minutes with gradual increases 1, 2. Consider continuous nasogastric ORS infusion if oral administration fails 1, 2.

Red Flags Requiring Urgent Referral

Refer immediately to gastroenterology or infectious disease specialists when:

• Signs of severe dehydration or shock are present 1, 3
• Bloody or mucoid stools occur 6, 7
• Persistent fever continues 1, 5
• Immunocompromise or recent hospitalization 5, 7
• Weight loss, anemia, or palpable abdominal mass 6

Common Pitfalls to Avoid

• Do not allow thirsty patients to drink large volumes ad libitum—this worsens vomiting; use small frequent volumes instead 1
• Do not use sports drinks, apple juice, or soft drinks for rehydration—their high osmolality is inappropriate 1, 3
• Do not "rest the bowel" through fasting—early refeeding improves outcomes 1, 3
• Do not give antimotility agents to children or patients with bloody/febrile diarrhea—risk of toxic megacolon 1
• Do not prescribe empiric antibiotics routinely—most cases are viral and self-limited 1, 5