(444) Synergistic Hepatotoxicity: Acute Liver Failure After Isopropyl and Ethanol Ingestion

Introduction: Acute liver injury, a complex liver disorder, can be caused by various drugs, herbs, alcohols, and dietary supplements. Per EASL guidelines, it is defined by ALT ≥5× ULN, ALP ≥2× ULN (with elevated GGT), or ALT ≥3× ULN with TB >2× ULN. This case report highlights an acute liver injury resulting from the co-ingestion of isopropyl alcohol and ethanol.

Description: A 61-year-old Caucasian male presented with drowsiness and nausea after consuming mouthwash and rubbing alcohol. He had a history of heavy alcohol use (1 liter/day), alcohol use disorder, major depressive disorder and peripheral neuropathy. Home medications included acamprosate, venlafaxine, thiamine, pyridoxine, and gabapentin. On examination, he was alert, oriented, and appeared intoxicated. Vitals were BP 124/81 mmHg, pulse 101 bpm, temperature 99.0°F, SpO2 94% on 4 L/min nasal cannula, and respiratory rate 18 bpm. Physical exams were unremarkable. Labs showed anion gap 9 mmol/L, bicarbonate 27 mmol/L, AST 1213 U/L, ALT 1378 U/L, ALP 76 U/L, total bilirubin 0.6 mg/dL, direct bilirubin 0.2 mg/dL, GGT 132 U/L, INR 1.32, PT 15.3 sec, lactic acid 3.0 mmol/L, beta hydroxy butyrate 4.7 mg/dL, and blood ethanol level 363 mg/dL. Viral hepatitis panel, urine toxicology, and imaging were normal. Treatment included saline bolus, lactated Ringer's infusion, N-acetylcysteine, thiamine, folic acid, and lorazepam. Liver function improved significantly over 3 days, but the patient was lost to follow-up after discharge.

Discussion: Isopropyl alcohol, found in disinfectants and rubbing alcohol, is rapidly absorbed, peaking in serum concentration about an hour after ingestion. Small amounts of co-ingested ethanol can block isopropyl alcohol metabolism, slowing elimination. Isopropanol toxicity often presents with altered mental status, resembling ethanol intoxication, without causing elevated anion gap acidosis but with severe ketonemia. After excluding infectious, metabolic, and autoimmune liver failure causes, the patient's liver injury, marked by elevated AST and ALT levels and severe ketonemia without high anion gap metabolic acidosis, was linked to the co-ingestion of isopropyl alcohol and ethanol-based mouthwash. This case report highlights an uncommon instance of acute liver injury following such co-ingestion.