# Acute Diarrhoea in Children

> Acute diarrhoea in children for NEET-PG Paediatrics: WHO dehydration plans, reduced-osmolarity ORS, zinc dosing and dysentery management notes.

- Canonical URL: https://prepelephant.com/topics/neet-pg/paediatrics/acute-diarrhoea-in-children
- Exam / course: NEET-PG · Subject: Paediatrics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Acute Diarrhoea in Children", PrepElephant, https://prepelephant.com/topics/neet-pg/paediatrics/acute-diarrhoea-in-children

## Direct answer

Acute diarrhoea kills children through dehydration, so assessment revolves around fluid status rather than the stool organism: WHO classifies dehydration as none, some or severe, and assigns Plans A, B and C — home fluids with continued feeding, oral rehydration with 75 mL/kg over four hours, or rapid intravenous rehydration. Every episode receives ORS plus zinc for 14 days, and feeding is never stopped. Dysentery — bloody, mucoid stool — is treated as bacterial (shigellosis above all) with an antibiotic, while antidiarrhoeal agents have no place in children.

## What you must remember

- **Dehydration assessment:** general condition, eyes, thirst and skin pinch classify dehydration as none (Plan A), some (Plan B) or severe (Plan C); lethargy, inability to drink and a very slow pinch mean severe dehydration.
- **Reduced-osmolarity ORS:** the WHO formulation of 245 mOsm/L — sodium 75, chloride 65, glucose 75, potassium 20 and citrate 10 mmol/L; glucose-linked sodium absorption survives toxin-induced secretion, the basis of ORS.
- **Plan B:** ORS 75 mL/kg over four hours, reassessed and repeated. Plan C: intravenous Ringer's lactate 100 mL/kg — infants get 30 mL/kg in the first hour, then 70 mL/kg over five hours; older children 30 mL/kg in 30 minutes, then 70 mL/kg over two-and-a-half hours — switching to oral fluids early.
- **Zinc:** 20 mg elemental zinc daily for 14 days (10 mg under six months) — it shortens the episode and protects for months afterwards.
- **Feeding:** continue breastfeeding and age-appropriate feeding; avoid fruit juices and sugary drinks; extra meals after recovery aid catch-up growth.
- **Dysentery:** blood and mucus in stool, most often shigellosis, treated with azithromycin or ciprofloxacin per current national guidance; metronidazole for demonstrated amoebiasis.
- **What to avoid:** loperamide and other antimotility agents (ileus, CNS depression), unnecessary antibiotics in watery diarrhoea, and stopping feeds.

## Common confusion

The commonest confusion is between ORS as treatment of dehydration versus of diarrhoea: ORS does not reduce stool volume (rice-based ORS modestly does in cholera); it keeps the child alive while illness runs its course. The second is persistent diarrhoea — beyond 14 days — which shifts the differential toward lactose intolerance, malnutrition, giardiasis and immunodeficiency. Third, vomiting need not block oral therapy: small frequent sips usually succeed, and intractable vomiting means intravenous or nasogastric rehydration — never "dry and starve".

## Exam-focused takeaway

NEET-PG draws from a fixed pool: ORS composition and its glucose-sodium coupling, the zinc dose and duration, the plan-by-plan volumes, and the classification signs that assign plans. Vignettes give a child's condition, eyes, thirst and pinch and expect the plan; numbers questions expect 75 mL/kg over four hours and the Plan C rate split by age. Dysentery stems pair blood in stool with shigella and an antibiotic, and one-liners probe rotavirus as the commonest cause of severe dehydrating diarrhoea in young children.

## Frequently asked questions

### What is the composition of WHO reduced-osmolarity ORS?

Sodium 75, chloride 65, glucose 75, potassium 20 and citrate 10 mmol/L — a total osmolarity of 245 mOsm/L.

### Why does ORS work despite secretory diarrhoea?

Glucose-coupled sodium absorption remains intact even in toxin-mediated secretion, so ORS drives water absorption regardless of stool losses.

### What is the dose of zinc?

20 mg of elemental zinc daily for 14 days, halved to 10 mg in infants under six months.

### How is severe dehydration treated?

Intravenous Ringer's lactate 100 mL/kg: infants get 30 mL/kg in the first hour and 70 mL/kg over five hours; older children get 30 mL/kg in 30 minutes and 70 mL/kg over two-and-a-half hours.

### Which children need an antibiotic?

Those with dysentery (usually shigella), suspected cholera, proven protozoal infection or associated sepsis — watery non-dysenteric diarrhoea does not.