Thrombocytopenia following acute acetaminophen overdose.

An unusual case of severe thrombocytopenia following acetaminophen overdose is presented along with a retrospective review of 174 patients with hospital admissions for acute acetaminophen toxicity. Thrombocytopenia occurred in 3.4% of these patients and strongly correlated with the degree of hepatotoxicity (as measured by peak AST values) but did not correlate with serum acetaminophen levels. The mechanism appears to be a transient direct toxic effect on platelets or megakaryocytes, and the finding of thrombocytopenia early in the course of acetaminophen overdose may identify a subset of patients at risk for significant hepatotoxicity.