Section: USMLE

57) A 15-year-old is brought to the emergency department in a coma. An alert ambulance attendant notes that the patient's breath smells like acetone. This observation is most consistent with which of the following diagnoses?

1. Alcohol intoxication
2. Diabetic hyperosmolar coma
3. Diabetic ketoacidosis
4. Heroin overdose
5. Profound hypoglycemia

The smell of acetone on the breath of a comatose patient is an important, rapid diagnostic clue that strongly suggests ketoacidosis and is usually seen in patients with poorly controlled type 1 diabetes. Other features of diabetic ketoacidosis include high blood glucose, increased serum osmolality, hypovolemia, acidosis, and electrolyte imbalance.

In alcohol intoxication, the breath will smell like alcohol.

Diabetic hyperosmolar coma usually is seen in older patients with type 2 diabetes and is not characterized by ketoacidosis. Since there is no acetone production, there is no specific scent to the breath.

In heroin overdose, no acetone production occurs and there is no specific scent to the breath.

In hypoglycemic coma, which can occur in diabetics with insulin overdose, no acetone production occurs and there is no specific scent to the breath.