Central DI — RACP Paediatrics MCQ

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ModerateEndocrineCentral DIRACP Paediatrics

A 5-year-old has polyuria (5 L/day). Serum osmolality 305, urine osmolality 120. After DDAVP, urine concentrates to 650. MRI: absent posterior pituitary bright spot. What is the diagnosis?

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Correct answer: E — Central DI

Elevated serum osm with dilute urine that concentrates after DDAVP = central DI. Absent posterior pituitary bright spot is characteristic. Causes: idiopathic, tumour, post-surgical, infiltrative.

Reference: RCH Melbourne – 2023 – DI CPG