A depressed mental status with extremely high glucose on a glucometer (>700 mg/dL) and an anion gap of 9 with Glu 1148 mg/dL suggests which diabetic emergency?

• A. DKA
• B. Diabetes insipidus
• C. HHNK
• D. Pheochromocytoma

Answer: (C)

Very high blood glucose with altered mental status and a normal anion gap points to a Hyperosmolar Hyperglycemic State. In this scenario the glucose is dramatically elevated (1148 mg/dL), which drives profound osmotic diuresis and dehydration, leading to mental status changes. The normal anion gap indicates there isn’t a significant amount of ketoacids present, so there isn’t the metabolic acidosis that characterizes diabetic ketoacidosis. Diabetic ketoacidosis usually shows a noticeable anion gap due to ketoacids, and glucose is typically lower, with acidosis and ketones present. Diabetes insipidus wouldn’t produce such extreme hyperglycemia with this lab pattern, and pheochromocytoma isn’t defined by this combination of extremely high glucose and normal anion gap. So the presentation best fits Hyperosmolar Hyperglycemic State.