Hyperosmolar Hyperglycaemic State — FRCA Final MCQ

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HardIntensive Care MedicineHyperosmolar Hyperglycaemic StateFRCA Final

A 62-year-old woman with type 2 diabetes is reviewed on the second day after an open right hemicolectomy. She is febrile at 38.6°C, tachycardic, confused and clinically dehydrated, with urine output of 0.3 mL/kg/hour. Laboratory results are: plasma glucose 38 mmol/L, sodium 130 mmol/L, urea 24 mmol/L, pH 7.31, bicarbonate 16 mmol/L and capillary ketones 2.8 mmol/L. What is the most likely metabolic diagnosis?

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Correct answer: E — Hyperosmolar hyperglycaemic state

The diagnosis is hyperosmolar hyperglycaemic state. She has clinical hypovolaemia, marked hyperglycaemia and a calculated osmolality of 322 mOsm/kg. Her ketones are no greater than 3 mmol/L, pH remains above 7.3 and bicarbonate is at least 15 mmol/L, matching the JBDS characteristic features of HHS. DKA is not the best diagnosis because significant ketonaemia and the requisite ketoacidosis are absent. Fever suggests that postoperative infection may have precipitated HHS, but stress hyperglycaemia alone does not adequately describe the associated hyperosmolality, dehydration and neurological disturbance. SIADH causes hypotonic hyponatraemia rather than a hyperosmolar state. Adrenal crisis usually causes hypotension, hyponatraemia and hypoglycaemia. Initial HHS treatment prioritises cautious 0.9% sodium chloride replacement and treatment of the precipitant; insulin is not routinely started immediately unless significant ketonaemia is present or osmolality/glucose fails to fall adequately with fluids.

Reference: Mustafa OG, Haq M, Dashora U, Castro E, Dhatariya KK; Joint British Diabetes Societies for Inpatient Care Group. Management of Hyperosmolar Hyperglycaemic State (HHS) in Adults: an updated guideline, 2023. https://pubmed.ncbi.nlm.nih.gov/36370077/