Hyperosmolar hyperglycaemic state — SCE Endocrinology MCQ

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HardDiabetic emergenciesHyperosmolar hyperglycaemic stateSCE Endocrinology

A 78-year-old care-home resident with type 2 diabetes is admitted with confusion and dehydration after a chest infection. Glucose is 46 mmol/L, ketones 0.4 mmol/L, measured osmolality 338 mOsm/kg and venous pH is 7.36. What is the most likely diagnosis?

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Correct answer: A — Hyperosmolar hyperglycaemic state

Hyperosmolar hyperglycaemic state is best because severe hyperglycaemia with hyperosmolality, dehydration and minimal ketonaemia is typical of HHS. The alternatives are less appropriate because DKA requires significant ketonaemia and acidosis; metformin lactic acidosis is lactate-driven; starvation ketosis is usually lower glucose; cerebral salt wasting does not explain hyperosmolality. The SCE teaching point is to integrate the clinical pattern, biochemistry and context rather than treating an isolated result.

Reference: JBDS-IP HHS guideline