skip to main content

Cranial diabetes insipidus — SCE Endocrinology MCQ

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

ModeratePituitaryCranial diabetes insipidusSCE Endocrinology

A 31-year-old woman has polydipsia and polyuria. During water deprivation, urine osmolality remains 110 mOsm/kg and rises to 620 mOsm/kg after desmopressin. Serum sodium is 149 mmol/L. What is the most likely diagnosis?

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

Reveal the answer and explanation

Correct answer: D — Cranial diabetes insipidus

Failure to concentrate urine during dehydration with marked response to desmopressin indicates cranial diabetes insipidus. Nephrogenic DI shows little response to desmopressin. Primary polydipsia usually concentrates urine with deprivation once medullary washout improves.

Reference: Society for Endocrinology Diabetes Insipidus Guidance