A 45-year-old woman is brought to the emergency department after neighbors found her unresponsive at home. No other history is available.
Temperature is 37 C (98.5 F), blood pressure is 100/70 mm Hg, pulse is 90/min, and respirations are 16/min. Pulse oximetry is 96% on room air. The patient is lethargic but arousable, and her speech is slurred. She is oriented to person but not place or time. There are no focal neurologic findings. The remainder of the physical examination is unremarkable.
Laboratory results are as follows:
Blood alcohol levels are undetectable.
Which of the following conditions is the most likely diagnosis?

Question

A 45-year-old woman is brought to the emergency department after neighbors found her unresponsive at home.  No other history is available.
Temperature is 37 C (98.5 F), blood pressure is 100/70 mm Hg, pulse is 90/min, and respirations are 16/min.  Pulse oximetry is 96% on room air.  The patient is lethargic but arousable, and her speech is slurred.  She is oriented to person but not place or time.  There are no focal neurologic findings.  The remainder of the physical examination is unremarkable.
Laboratory results are as follows:
 Blood alcohol levels are undetectable.
Which of the following conditions is the most likely diagnosis?

Quizplus · Accepted Answer

11ec193a_96aa_b527_853d_7553ec052134_MD0002_00 This patient has altered mental status, elevated osmolar gap without an anion gap metabolic acidosis (AGMA), elevated urine ketones, and undetectable blood alcohol levels. This constellation of findings raises suspicion for isopropyl alcohol ingestion. osmolar gap Isopropyl alcohol, like ethanol, is a central nervous system depressant. It is rapidly metabolized by alcohol dehydrogenase to the ketone acetone, leading to elevated serum and urine ketone measurements. Some laboratories measure beta-hydroxybutyrate concentrations as a substitute for serum ketones, leading to a falsely low measurement in patients with isopropyl alcohol ingestion. Unlike methanol and ethylene glycol, isopropyl alcohol does not cause high AGMA and does not have toxic metabolites causing further damage (eg, blindness, renal failure). Massive ingestions can cause respiratory depression and hypotension. Treatment is mainly supportive with intravenous fluids, pressors, and mechanical ventilation; hemodialysis can be initiated in severe cases. Fomepizole and gastrointestinal decontamination are usually not helpful. (Choice A) Ethanol is the most common cause of an elevated osmolar gap; the contribution of ethanol to serum osmolality can be calculated by dividing the serum ethanol level by 4. Isolated ethanol ingestion causes only an elevated osmolar gap (without AGMA). By contrast, alcoholic ketoacidosis occurs when patients with long-standing alcohol abuse and poor nutritional status have an episode of binge drinking, leading to ketosis (with AGMA). This patient's normal blood alcohol level and anion gap rule out alcoholic ketoacidosis. (Choice B) Diabetic ketoacidosis presents with ketonuria and an osmolar gap; however, a high AGMA, elevated blood glucose (>250 mg/dL), and elevated serum β-hydroxybutyrate levels are usually present. (Choice D) Salicylate intoxication causes high AGMA and respiratory alkalosis. The osmolar gap is normal in these patients. (Choice E) Starvation ketoacidosis (due to lipolysis with formation of free fatty acids and conversion into ketones) also causes ketonuria and an osmolar gap. However, these patients typically have a high AGMA. Educational objective: Patients with isopropyl alcohol ingestion have altered mental status, elevated osmolar gap, normal anion gap, and ketonuria/ketonemia. Treatment is mainly supportive. __________ References: Isopropanol poisoning. (http://www.ncbi.nlm.nih.gov/pubmed/24815348)

A 45-Year-Old Woman Is Brought to the Emergency Department After