Board Review: Pick your poison!
A 55-year-old male presents to the ED with presumed alcohol intoxication. He has a history of alcoholism and is well known to the ED staff as he often arrives intoxicated. His vital signs at triage are within normal limits and he is taken to a bed where he sleeps for many hours until he is signed out to you at the start of the next shift. Upon your reassessment, he still appears very intoxicated and you notice he has fruity breath. A VBG is normal. What is the metabolite of this patient’s most likely ingestion?
A. Formic Acid
B. Oxalic Acid
C. Acetone. This patient has been intoxicated in your ED for so long that he was signed out to you on the next shift. This should prompt you to reassess the patient and expand your differential diagnosis to toxic alcohols including the most likely culprit in this case - isopropanol, which is metabolized by ADH to acetone, which can produce fruity odor to breath. A component of rubbing alcohol and hand sanitizers, isopropanol is the most commonly ingested toxic alcohol, often used by patients as a substitute for ethanol. It produces hemorrhagic gastritis as well as more severe and longer lasting inebriation compared to ethanol. The treatment for this is primarily supportive care, however keep in mind that CNS depression can be so severe that a definitive airway may be required. Methanol and ethylene glycol ingestion is not likely in this case as they would produce an anion gap metabolic acidosis as well as other symptoms. If serum levels of methanol or ethylene glycol are >20 mg/dL, the antidote fomepizole should be initiated. In these cases, sodium bicarbonate and hemodialysis may also be required for severe acidosis, hemodynamic instability, or renal failure.
See this prior EM Daily post regarding toxic alcohols: https://emdaily.cooperhealth.org/content/emconf-toxic-alcohols