Acute Diarrhoea in Children - A Comprehensive Overview

Definition

• Acute diarrhoea: < 14 days
• Persistent diarrhoea: ≥ 14 days
• Dysentery: diarrhoea with blood in the stool

Epidemiology & Global Burden

Etiology and Classification of Acute Diarrhoea

By Mechanism (Pathophysiology)

By Etiology

• Viral (most common overall): Rotavirus (leading cause of severe dehydration in children under 5), Norovirus, Adenovirus, Astrovirus. Rotavirus vaccination has made it less prevalent in vaccinated populations.
• Bacterial: E. coli (ETEC, EPEC, EHEC), Shigella, Salmonella, Campylobacter, V. cholerae, Clostridium difficile
• Parasitic: Giardia lamblia, Entamoeba histolytica, Cryptosporidium

• Lactose malabsorption
• Small bowel bacterial overgrowth
• Allergic enteropathy / cow's milk protein allergy
• Cystic fibrosis
• Hirschsprung disease
• Medications (antibiotics)

WHO IMCI Classification of Diarrhoea (Pediatric)

A. Classification for Dehydration

Assessment Signs (Look and Feel):

1. General condition: Lethargic/unconscious? Restless and irritable?
2. Eyes: Sunken?
3. Thirst: Not able to drink / drinking poorly? Or drinking eagerly / thirsty?
4. Skin pinch: Goes back very slowly (>2 seconds)? Slowly? Or immediately?

Dehydration Classification Table (WHO/IMCI)

B. Classification by Duration

C. Percentage Dehydration (Clinical/Weight-Based)

Management

Overview

PLAN A: No Dehydration - Home Treatment

• Breastfed: breastfeed frequently and for longer
• Non-exclusively breastfed: ORS, food-based fluids (soup, rice water, yoghurt drinks), or clean water

• Give frequent small sips from a cup
• If the child vomits, wait 10 minutes, then continue more slowly

• 2 months - 6 months: 10 mg/day for 10-14 days
• 6 months - 5 years: 20 mg/day for 10-14 days
• For infants: dissolve in breast milk, ORS or clean water
• For older children: chew or dissolve in small amount of water

• Exclusive breastfeeding if age < 6 months
• Do NOT restrict food - early refeeding prevents malnutrition

• Cannot drink or breastfeed
• Becomes sicker
• Develops fever
• Blood in stool

PLAN B: Some Dehydration - ORS in Clinic Over 4 Hours

• Give frequent small sips from a cup
• If vomiting: wait 10 minutes, then restart more slowly
• Continue breastfeeding whenever the child wants
• After 4 hours: Reassess and classify dehydration, select appropriate plan, begin feeding in clinic

PLAN C: Severe Dehydration - Treat Quickly

• Start IV fluids with Ringer's Lactate solution (or normal saline if RL unavailable): 100 mL/kg total

• Reassess every 1-2 hours; if not improving, give IV drip more rapidly
• Also give ORS (~5 mL/kg/hour) as soon as child can drink: after 3-4 hours (infants) or 1-2 hours (children)
• Reassess after 6 hours (infants) or 3 hours (children), then choose appropriate plan

• Refer URGENTLY to hospital; give ORS sips on the way

• ORS via NG: 20 mL/kg/hour for 6 hours (120 mL/kg total)
• Reassess every 1-2 hours

• Refer URGENTLY for IV or NG treatment

WHO Oral Rehydration Solution (ORS) Composition

Additional Management Measures

Dietary Management

• Do not restrict food - early refeeding reduces intestinal permeability and duration of illness
• Resume regular age-appropriate diet as soon as tolerated
• Avoid high-sugar drinks (juice, soft drinks) - osmotic worsening
• Breastfeeding should never be interrupted

Pharmacotherapy

• Non-specific antidiarrheal agents: No supporting evidence for routine use
• Antimotility agents (loperamide): NOT recommended in children with acute infectious diarrhoea - risk of ileus, toxic megacolon
• Antisecretory drugs, toxin binders (cholestyramine): No evidence of benefit
• Antibiotics: Only for specific indications:
  • Shigella dysentery: azithromycin or ciprofloxacin
  • V. cholerae: doxycycline (>8 years) or azithromycin
  • Giardia: metronidazole or tinidazole
  • C. difficile: oral vancomycin or metronidazole
  • Cholera in children ≥ 2 years if cholera in area
• Probiotics: Limited but demonstrated evidence in antibiotic-associated diarrhoea and severe recurrent C. difficile

Zinc Supplementation

• 10-14 day course of zinc reduces duration, severity, and risk of future episodes
• Recommended by WHO for all children 2 months - 5 years with acute diarrhoea

Parenteral Hydration

• Severe dehydration
• Hemodynamic instability
• Failure of ORT (persistent vomiting, ileus)
• Altered consciousness

When to Refer / Red Flags

• Severe dehydration (Plan C criteria)
• Blood in stool (dysentery) with systemic toxicity
• Persistent diarrhoea ≥ 14 days
• Signs of shock (cold extremities, weak/absent pulse, altered consciousness)
• Failure to improve after rehydration
• Age < 6 months with signs of dehydration
• Concurrent severe illness (pneumonia, meningitis)

Prevention

• Rotavirus vaccination (dramatically reduces burden in children < 5 years)
• Exclusive breastfeeding for the first 6 months
• Safe drinking water and sanitation (WASH)
• Proper hand hygiene / hand-washing with soap
• Safe food preparation
• Continued breastfeeding during illness

Summary Flow

Acute Diarrhoea in a Child
        |
Assess Dehydration (IMCI Criteria)
        |
   _____|_______________
   |         |         |
No Dehy  Some Dehy  Severe Dehy
   |         |         |
Plan A    Plan B    Plan C
(Home)  (ORS 4 hr  (IV fluids
        in clinic)  urgently)
        |
All Plans: Zinc + Continue Feeding + When to Return

• Park's Textbook of Preventive and Social Medicine (IMCI Management Plans A, B, C)
• The Harriet Lane Handbook, 23rd Ed. (Differential diagnosis and pharmacotherapy)
• Harrison's Principles of Internal Medicine, 22nd Ed. (WHO-ORS composition)
• ROSEN's Emergency Medicine (Etiology - rotavirus, norovirus)

Recent WHO Guidelines on Acute Diarrhoea Management in Children

Landmark 2024 WHO Guideline

Why This Guideline Matters

• Pneumonia and diarrhoea together account for 23% of under-five mortality - approximately 1.17 million deaths in children under 5 in 2021
• In children 5-9 years, these same two conditions caused ~86,000 preventable deaths in 2021 - a group previously without dedicated WHO guidance

Key Recommendation Changes from Previous WHO Guidance

1. Extended Age Range

• Recommendations now apply to children up to 10 years (previously up to 5 years)
• The same core diarrhoea management principles apply - ORS + zinc + continued feeding - but now formally cover the 5-9 year age group

2. New Zinc Dose - Most Important Clinical Update

Critical Transitional Note (as of July 2026): Per UNICEF Supply Division (updated 6 July 2026): "As 5 mg zinc tablets are not yet commercially available, WHO and UNICEF advise continued use of the established 20 mg per day for 14 days." The new 5 mg formulation is the target but supply has not yet caught up. Zinc gluconate is the preferred salt going forward.

3. ORS Recommendations - Unchanged Core, Extended Age

• Low-osmolarity ORS remains the standard of care for acute watery diarrhoea and dehydration in children up to 10 years
• ORS composition unchanged: Na⁺ 75 mmol/L, K⁺ 20 mmol/L, Cl⁻ 65 mmol/L, Citrate 10 mmol/L, Glucose 75 mmol/L, total osmolarity 245 mOsm/L
• The Plan A / Plan B / Plan C framework remains the basis of management

4. Pneumonia-Specific Changes (Context)

• Greater scope for community-level pneumonia treatment
• New clinical signs to diagnose hypoxaemia when pulse oximetry is unavailable

Core WHO Diarrhoea Recommendations Reaffirmed (2024)

China 2024 Clinical Practice Guidelines - Key Updates

• Probiotics: Moderately advised for viral watery diarrhoea (modest evidence)
• Racecadotril (antisecretory): Remains unsupported by current evidence
• Zinc: Recommended for children >6 months in zinc-deficient regions
• Antibiotics: Restricted to:
  • Dysenteric-like symptoms
  • Suspected cholera with severe dehydration
  • Cases with significant comorbidities
• Etiological diagnosis: Standardised evaluation now guides management decisions

Global Burden Reminder (2024 Data)

• Diarrhoea caused ~374,000 deaths in children under 5 in 2024
• ~40,000 deaths in children aged 5-9 in 2024
• Nearly 1.7 billion children fall ill with diarrhoea every year
• 93% of deaths concentrated in low- and middle-income countries
• ORS + zinc, if fully deployed, could prevent up to 93% of diarrhoea deaths

Summary: What Changed vs. What Stayed the Same