Which tests are indicated in patients with mental status changes due to acetaminophen toxicity/poisoning, and what lab findings are associated with hepatotoxicity?

Updated: Jan 17, 2020
  • Author: Susan E Farrell, MD; Chief Editor: Michael A Miller, MD  more...
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In patients with mental status changes, strongly consider serum ammonia levels and CT scanning of the brain. Laboratory findings in the phases of acetaminophen hepatotoxicity are as follows:

  • Phase 1: Approximately 12 hours after an acute ingestion, liver function studies show a subclinical rise in serum transaminase concentrations (ALT, AST)

  • Phase 2: Elevated serum ALT and AST, PT, and bilirubin concentration; renal function abnormalities may also be present and indicate nephrotoxicity

  • Phase 3: Severe hepatotoxicity is evident on serum studies; hepatic centrilobular necrosis is diagnosed on liver biopsy

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