What is the management approach for acute infectious diarrhea?

Management of Acute Infectious Diarrhea

The cornerstone of managing acute infectious diarrhea is oral rehydration therapy with reduced osmolarity ORS for mild-to-moderate dehydration, early refeeding with age-appropriate diet, and avoidance of empiric antibiotics in most cases. 1

Initial Assessment

Assess hydration status immediately upon presentation:

• Mild dehydration (3-5% fluid deficit): Slightly dry mucous membranes, normal mental status, adequate urine output 1
• Moderate dehydration (6-9% fluid deficit): Sunken eyes, decreased skin turgor, reduced urine output 1
• Severe dehydration (≥10% fluid deficit): Altered mental status, poor perfusion, weak pulse, shock—this is a medical emergency 1

Determine diarrhea type to guide management:

• Watery diarrhea: Focus on rehydration; empiric antibiotics NOT recommended 1
• Bloody diarrhea (dysentery): Consider empiric antibiotics in specific circumstances 1

Rehydration Strategy

Mild-to-Moderate Dehydration

Administer reduced osmolarity ORS (50-90 mEq/L sodium) as first-line therapy 1:

• Mild dehydration: 50 mL/kg over 2-4 hours 1
• Moderate dehydration: 100 mL/kg over 2-4 hours 1
• Start with small volumes (one teaspoon) using syringe or medicine dropper, gradually increasing as tolerated 1
• Reassess hydration status after 2-4 hours 1

If oral intake fails: Consider nasogastric ORS administration in children with normal mental status who are too weak or refuse to drink 1

Severe Dehydration

Immediate IV rehydration is mandatory 1:

• Administer isotonic fluids (lactated Ringer's or normal saline) in 20 mL/kg boluses until pulse, perfusion, and mental status normalize 1
• May require two IV lines or alternate access (venous cutdown, femoral vein, intraosseous) 1
• Continue IV therapy until patient awakens, has no aspiration risk, and no ileus 1
• Transition to ORS for remaining deficit once mental status normalizes 1

Ongoing Losses

Replace continuing stool and vomit losses throughout treatment 1:

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

Nutritional Management

Resume age-appropriate diet immediately after rehydration or during the rehydration process 1:

• Breastfed infants: Continue nursing on demand throughout the illness 1
• Bottle-fed infants: Use full-strength lactose-free or lactose-reduced formulas immediately upon rehydration 1
• Older children and adults: Resume normal diet guided by appetite; avoid fatty, heavy, spicy foods and caffeine 2

Antimicrobial Therapy

Watery Diarrhea

Empiric antibiotics are NOT recommended for most patients with acute watery diarrhea 1:

• Exceptions: Immunocompromised patients or ill-appearing young infants may receive empiric treatment 1
• Avoid empiric treatment in persistent watery diarrhea lasting ≥14 days 1

Bloody Diarrhea

Consider empiric antibiotics in specific circumstances 1:

• Adults: Fluoroquinolone or azithromycin based on local susceptibility patterns and travel history 1
• Children: Third-generation cephalosporin for infants <3 months or those with neurologic involvement; azithromycin for others based on local patterns 1
• Immunocompromised patients: Empiric treatment recommended with severe illness and bloody diarrhea 1

Critical Contraindication

Avoid antibiotics in STEC O157 and other STEC producing Shiga toxin 2 due to risk of hemolytic uremic syndrome 1

Enteric Fever

Treat empirically with broad-spectrum antibiotics after obtaining blood, stool, and urine cultures in patients with sepsis features 1

Adjunctive Medications

Antimotility Agents

Loperamide use is highly age-restricted 1:

• CONTRAINDICATED in children <18 years with acute diarrhea 1
• Adults with watery diarrhea: May use loperamide (initial 4 mg, then 2 mg after each unformed stool, maximum 16 mg daily) 2, 3
• Avoid in ALL ages with inflammatory diarrhea, fever, or bloody stools due to toxic megacolon risk 1

Antiemetics

Ondansetron may facilitate oral rehydration in children >4 years and adolescents with vomiting 1:

• Use only after adequate hydration begins 1
• Not a substitute for fluid and electrolyte therapy 1

Probiotics

May offer modest benefit to reduce symptom severity and duration in immunocompetent patients 1:

• Evidence is moderate quality; specific organism selection varies 1

Zinc Supplementation

Recommended for children 6 months to 5 years in countries with high zinc deficiency prevalence or signs of malnutrition 1

Infection Control

Rigorous hand hygiene is essential 1:

• Perform after toilet use, diaper changes, before food preparation and eating, after handling garbage or animals 1
• Use gloves, gowns, and soap-and-water or alcohol-based sanitizers when caring for patients with diarrhea 1

Asymptomatic contacts do NOT require treatment except Salmonella typhi carriers who may be treated to reduce transmission 1

Common Pitfalls to Avoid

• Never withhold feeding: Early refeeding prevents nutritional deterioration and does not prolong diarrhea 1
• Never use antimotility agents in children: Strong evidence of harm in pediatric populations 1
• Never give antibiotics for suspected STEC: Increases hemolytic uremic syndrome risk 1
• Never use IV fluids when oral rehydration succeeds: ORS is equally effective and less invasive for mild-moderate dehydration 1
• Never prescribe empiric antibiotics for uncomplicated watery diarrhea: Promotes resistance without benefit 1