MBBS SAQ · Paediatrics
Acute gastroenteritis with dehydration — WHO Plans A/B/C and zinc
NEET-PG SAQ on paediatric AGE: WHO dehydration table, ORS 75 mL/kg Plan B, Plan C IV phases, zinc dosing, danger signs, and ORS mechanism.
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Question
A 10-month-old infant has had 8 watery stools and 4 vomits in 24 hours. Weight 9 kg. Examination: irritable, sunken eyes, drinks eagerly, skin pinch goes back slowly, moist mucous membranes slightly reduced, warm extremities, HR 140, BP normal for age. No blood in stool. Classify dehydration, calculate and describe fluid therapy, adjuncts, danger signs, and when to use IV Plan C instead. [1]
Model answer
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Classification: SOME dehydration → WHO Plan B.
Two or more of: restlessness/irritability, sunken eyes, drinks eagerly/thirsty, skin pinch slow → some dehydration. Not severe (not lethargic/unable to drink/skin pinch very slow).[1]
Plan B — ORS rehydration in facility:
- Volume: 75 mL/kg over 4 hours → 9 × 75 = 675 mL ORS over 4 h.[1]
- Give frequent small sips (cup/spoon); NG ORS if persistent vomiting but conscious.
- Continue breastfeeding/age-appropriate feeds; after rehydration, extra fluid after each stool as in Plan A (WHO 2005: 50–100 mL if under 2 years).[1]
- Reassess at 4 hours: improved → Plan A home ORS; same → repeat Plan B; worse/unable to drink → Plan C.
Plan A (after recovery / no dehydration): home ORS after each stool, continue feeding, zinc, counsel return precautions. [1]
Plan C (severe dehydration — know even if not this child): IV Ringer’s lactate (or NS if RL unavailable): [1]
- Infants <12 months: 30 mL/kg in first 1 h, then 70 mL/kg over next 5 h (total 100 mL/kg over 6 h).[1]
- Children ≥12 months: 30 mL/kg in 30 min, then 70 mL/kg over 2.5 h (total 100 mL/kg over 3 h).[1]
- Start ORS by NG/oral as soon as able; reassess continuously; treat shock first if present.
Adjuncts:
- Zinc: WHO 2005 10–20 mg daily for 10–14 days for all children with diarrhoea.[1] Dhingra cites WHO 20 mg/day for 10–14 days; Cochrane does not support benefit under 6 months.[2][3]
- Antiemetic: ondansetron single dose may help selected vomiting children older than ~6 months (local protocol); avoid antimotility agents (loperamide) in young children.
- Antibiotics not routine for watery diarrhoea; consider for dysentery (Shigella), cholera, proven invasive disease, or immunocompromise.
ORS mechanism (exam pearl): glucose-coupled sodium absorption via SGLT1 remains intact in secretory diarrhoea → water follows. [1]
Danger signs for urgent return: inability to drink/breastfeed, repeated vomiting, lethargy, blood in stool, fever with toxicity, reduced urine, seizures. [1]
Common errors
- Giving Plan C IV fluids for some dehydration. [1]
- Wrong Plan B volume (not 75 mL/kg).[1]
- Stopping breastfeeding during rehydration.
- Routine antibiotics for watery diarrhoea.
- Omitting zinc.
- Using antimotility drugs in infants.
Examiner notes
- Reproduce WHO table language and Plan B 75 mL/kg/4 h. [1]
- State zinc 10–20 mg daily × 10–14 days (WHO 2005); do not invent a 10 mg-under-6 split from this manual.[1]
- Know Plan C time splits for <12 months vs older.[1]
- Mechanism: SGLT1 / glucose–sodium cotransport.
References3ShowHide
- [1]World Health Organization The treatment of diarrhoea: a manual for physicians and other senior health workers. 4th revision. World Health Organization, 2005.Source
- [2]Dhingra U, Kisenge R, Sudfeld CR, et al. Lower-Dose Zinc for Childhood Diarrhea - A Randomized, Multicenter Trial. New England Journal of Medicine, 2020.PMID 32966722
- [3]Lazzerini M, Wanzira H. Oral zinc for treating diarrhoea in children. Cochrane Database of Systematic Reviews, 2016.PMID 27996088