What is the recommended treatment for a patient with acute diarrhea?

Treatment of Acute Diarrhea: Oral Rehydration Solution

Reduced osmolarity oral rehydration solution (ORS) is the first-line treatment for acute diarrhea in patients of all ages with mild to moderate dehydration, and should be prescribed or provided to patients for home administration. 1

Assessment of Dehydration Severity

Before prescribing treatment, assess the degree of dehydration by examining:

• Skin turgor (pinch test on abdomen or thigh)
• Mucous membranes (dry vs. moist)
• Mental status (alert, lethargic, or unresponsive)
• Pulse quality and rate
• Capillary refill time 1

Categorize dehydration as:

• Mild (3-5% fluid deficit): Slightly dry mucous membranes, normal mental status
• Moderate (6-9% fluid deficit): Dry mucous membranes, sunken eyes, decreased skin turgor
• Severe (≥10% fluid deficit): Shock or near-shock, altered mental status, very poor perfusion 1

ORS Prescription and Administration Protocol

For Mild Dehydration (3-5% deficit)

• Prescribe ORS containing 50-90 mEq/L sodium 1
• Dosing: 50 mL/kg over 2-4 hours 1
• Administration technique: Start with small volumes (5-10 mL every 1-2 minutes using a teaspoon or syringe), then gradually increase as tolerated 1, 2
• Common pitfall: Avoid allowing thirsty patients to drink large volumes ad libitum, as this worsens vomiting 2

For Moderate Dehydration (6-9% deficit)

• Prescribe ORS containing 50-90 mEq/L sodium 1
• Dosing: 100 mL/kg over 2-4 hours 1
• Same administration technique as mild dehydration 1
• Alternative: Nasogastric ORS administration may be considered if oral intake is not tolerated 1

For Severe Dehydration (≥10% deficit, shock, altered mental status)

• This is a medical emergency requiring immediate intravenous rehydration 1
• Do not prescribe ORS for home use—refer immediately to emergency department 1
• IV therapy: Isotonic fluids (lactated Ringer's or normal saline) in 20 mL/kg boluses until pulse, perfusion, and mental status normalize 1
• Once stabilized, transition to ORS for remaining deficit replacement 1

Maintenance Therapy After Rehydration

Once rehydration is achieved:

• Replace ongoing stool losses: 10 mL/kg of ORS for each watery stool 1, 2
• Replace vomiting losses: 2 mL/kg of ORS for each episode of emesis 1, 2
• Continue ORS until diarrhea and vomiting resolve 1

Nutritional Management

• Continue breastfeeding throughout the diarrheal episode without interruption 1, 2
• Resume age-appropriate diet during or immediately after rehydration is completed 1
• For infants: Resume full-strength formula immediately upon rehydration (lactose-free or lactose-reduced preferred) 1, 2
• For older children: Starches, cereals, yogurt, fruits, and vegetables; avoid foods high in simple sugars and fats 1, 2

Adjunctive Therapies (NOT Substitutes for ORS)

Antiemetics

• Ondansetron may be prescribed for children >4 years of age with vomiting to facilitate ORS tolerance, but only after adequate hydration is achieved 1, 2

Antimotility Agents: Critical Contraindications

• Loperamide is absolutely contraindicated in all children <18 years of age 1, 3
• In adults: Loperamide may be given to immunocompetent adults with acute watery diarrhea, but avoid in bloody diarrhea, fever, or suspected inflammatory diarrhea due to risk of toxic megacolon 1
• FDA Warning: Loperamide is contraindicated in children <2 years due to risks of respiratory depression, cardiac arrest, and death 3

Probiotics

• May be offered to reduce symptom severity and duration in immunocompetent patients 1

Zinc Supplementation

• Recommended for children 6 months to 5 years of age who reside in countries with high zinc deficiency prevalence or show signs of malnutrition 1, 2
• Reduces diarrhea duration 1, 2

When Antibiotics Are NOT Indicated

• Empiric antibiotics are NOT recommended for most patients with acute watery diarrhea without recent international travel 1
• Antibiotics should be avoided in suspected or proven STEC O157 infections due to risk of hemolytic uremic syndrome 1

Red Flags Requiring Immediate Medical Attention

Instruct patients to return immediately if they develop:

• Bloody diarrhea (dysentery) 2
• Severe dehydration signs: sunken eyes, very poor skin turgor, altered mental status 1, 2
• Intractable vomiting preventing oral rehydration 2
• High stool output (>10 mL/kg/hour) 2
• Decreased urine output, lethargy, or irritability 2, 4
• No clinical improvement within 48 hours 3

Key Clinical Pitfalls to Avoid

• Do not prescribe antimotility drugs to children under any circumstances 1, 3
• Do not delay or dilute formula feeding after rehydration—this worsens outcomes 1, 2, 4
• Do not diagnose lactose intolerance based solely on stool pH or reducing substances without clinical symptoms 1, 4
• Do not allow ad libitum drinking in vomiting patients—use small, frequent volumes 2
• Do not use ORS as a substitute for IV fluids in severe dehydration or shock 1