What is the clinical course of acetaminophen toxicity/poisoning?

Updated: Jan 17, 2020
  • Author: Susan E Farrell, MD; Chief Editor: Michael A Miller, MD  more...
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The clinical course of acetaminophen toxicity generally is divided into four phases. Physical findings may vary, depending on the degree of hepatotoxicity.

Phase 1

  • 0.5-24 hours after ingestion
  • Patients may be asymptomatic or report anorexia, nausea or vomiting, and malaise
  • Physical examination may reveal pallor, diaphoresis, malaise, and fatigue

Phase 2

  • 18-72 h after ingestion
  • Patients develop right upper quadrant abdominal pain, anorexia, nausea, and vomiting
  • Right upper quadrant tenderness may be present
  • Tachycardia and hypotension may indicate volume losses
  • Some patients may report decreased urinary output (oliguria)

Phase 3: Hepatic phase

  • 72-96 h after ingestion
  • Patients have continued nausea and vomiting, abdominal pain, and a tender hepatic edge
  • Hepatic necrosis and dysfunction may manifest as jaundice, coagulopathy, hypoglycemia, and hepatic encephalopathy
  • Acute kidney injury develops in some critically ill patients
  • Death from multiorgan failure may occur

Phase 4: Recovery phase

  • 4 d to 3 wk after ingestion
  • Patients who survive critical illness in phase 3 have complete resolution of symptoms and complete resolution of organ failure

See Presentation for more detail.

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