skip to main content

Hypernatraemic dehydration — RACP Paediatrics MCQ

Instant feedback + full explanation. One question, done properly.

HardNephrologyHypernatraemic dehydrationRACP Paediatrics

A 2-year-old presents with a 3-day history of vomiting and diarrhoea. Serum sodium is 158 mmol/L. The child has signs of moderate dehydration. What is the most appropriate IV fluid for rehydration?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — 0.9% NaCl + 5% dextrose at maintenance rate

Hypernatraemic dehydration requires slow correction of sodium to avoid cerebral oedema. The deficit should be replaced slowly over 48 hours using 0.9% NaCl + 5% dextrose. Serum sodium should not fall by more than 0.5 mmol/L per hour (max 10-12 mmol/L per 24 hours). Frequent electrolyte monitoring is essential.

Reference: RCH Melbourne – 2023 – Dehydration CPG; RACP Paediatric Curriculum – Nephrology