Acetaminophen Overdose

Today we discussed our approach to Acetaminophen overdose or poisoning. I wanted to elaborate a bit more on the clinical progression of symptoms:

Initial: mild, non-specific

Stage I (0.5-24h): nausea, vomiting, diaphoresis, pallor, lethargy, malaise, asymptomatic;

o   Labs are often normal +/- enzyme elevation, CNS usually normal

Stage II (24-72h):

o   Hepatotoxicity: transaminase elevation, RUQ pain, elevation INR, Bilirubin

o   Nephrotoxicity: may see evidence of oliguria, elevated Urea, Cr

Stage III (72-96h)

o   Liver function abnormalities: peak; enzymes elevated, INR elevated, Bilirubin elevated, hypoglycemia, lactic acidosis

o   Worsening symptoms: jaundice, confusion, bleeding diasthesis, hepatic encephalopathy

o   AKI: primarily due to acute tubular necrosis and vascular endothelial damage & ischemia, with elevated Cr, urea, hematuria, proteinuria, granular/epithelial casts. Occurs in ~10% of severe poisonings

o   Death most commonly occurs in this stage *(from multi-organ failure)

Stage IV (4 days to 2 weeks): recovery may be slow, particularly in ill patients

o   Histological recovery lags behind clinical recovery, and may take up to 3 months 

Resources:
Rowden A, et al. Updates on acetaminophen toxicity. Med Clin N America 2005; 89: 1145-59