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Hyperosmolar hyperglycaemic state — SCE Acute Medicine MCQ

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ModerateDiabetes and endocrine medicineHyperosmolar hyperglycaemic stateSCE Acute Medicine

A 72-year-old man with type 2 diabetes presents with 5 days of thirst and confusion. Glucose is 48 mmol/L, ketones are 0.8 mmol/L, pH is 7.36, sodium is 152 mmol/L and calculated osmolality is 364 mOsm/kg. He is profoundly dehydrated but not hypotensive. What is the most appropriate next step in management?

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Correct answer: E — Start cautious intravenous 0.9% sodium chloride with frequent osmolality monitoring

HHS is primarily a profound dehydration and hyperosmolality state, so cautious 0.9% sodium chloride with gradual osmolality reduction is central; insulin is delayed or used at lower dose unless ketonaemia is significant. Rapid osmotic shifts can cause cerebral oedema or circulatory collapse. The high sodium reflects water deficit rather than a need for immediate hypotonic fluid in most cases.

Reference: Joint British Diabetes Societies guideline for HHS