In hyperosmolar hyperglycemic state, which characteristic best distinguishes it from diabetic ketoacidosis?

• A. Ketoacidosis is always present
• B. Severe dehydration with very high glucose and minimal ketoacidosis
• C. Rapid increase in insulin requirement
• D. Low serum osmolality

Answer: (B)

Hyperosmolar hyperglycemic state is driven by extreme hyperglycemia and profound dehydration that raises serum osmolality, with only minimal ketone production because there is enough insulin to suppress lipolysis. This combination creates very high glucose levels (often >600 mg/dL) and marked dehydration, but little or no metabolic acidosis. In contrast, diabetic ketoacidosis features significant ketosis and acidosis (anion gap) with lower-to-moderate glucose levels. So the hallmark distinguishing feature is severe dehydration with very high glucose and minimal ketoacidosis.