Toxicological

  • Acetaminophen Overdose
  • Beta-Blocker Overdose
  • Lithium Overdose

Acetaminophen Overdose

  • Background
    • Acetaminophen overdose occurs at doses of 150mg/kg within 24 hours,  causing delayed onset of severe liver injury and potentially liver failure due to the production of NAPQI from the parent compound. 
  • Signs/Symptoms
    • Symptoms: Nausea/vomiting at first, progresses to RUQ pain
    • Signs: jaundice, tachycardia, hypotension
  • Diagnosis
    • Acetaminophen (APAP) level; compare with Rumack-Matthew Nomagram
    • Liver function tests
  • Treatment
    • N-acetylcysteine (most beneficial if given within 8 hours of ingestion)
    • Supportive care (IV fluids, antiemetics)
Video Credit: LITreviews

*Deep Dive: Acetaminophen Toxicity (EMCRIT)



Beta-Blocker Overdose

  • Background
    •  Beta-blockers inhibit epinephrine and norepinephrine adrenergic stimulation on beta receptors; overdose can cause bradycardia, hypotension, and ultimately cardiovascular collapse. 
  • Signs/Symptoms
    • Symptoms: Fatigue, nausea, weakness
    • Signs: (+) Hypotension, (+) bradycardia
  • Diagnosis
    • Clinical diagnosis based on history and clinical features
    • Routine drug screens not usually helpful
  • Treatment
    • Maintain hemodynamics (IV fluids, vasopressors)
    • Consider glucagon and atropine
Video Credit: Doctors Writing DW

*Deep Dive: Beta Blocker Toxicity (NUEM Blog)



Lithium Overdose

  • Background
    • Lithium is used primarily to treat bipolar disorder. Toxicity can cause GI, neurologic, and renal manifestations.
  • Signs/Symptoms
    • Predominantly GI symptoms initially (nausea, vomiting, cramping, diarrhea)
    • Progression of toxicity can cause dystonia, ataxia, hyperreflexia, and cardiac dysrhythmias.
  • Diagnosis
    • Lithium level (may not correlate with clinical symptoms)
    • Consider testing for coingestants (ex. Acetaminophen)
  • Treatment
    • GI decontamination (whole bowel irrigation, gastric lavage)
    • Enhanced elimination (IV fluids, diuretics, hemodialysis)
Video Credit: Lecturio

*Deep Dive: Lithium Intoxication (EMCRIT)


Brandon Simpson, PA-S2
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