We present a patient who developed a mononucleosis syndrome 6 weeks after starting phenytoin therapy for a seizure disorder. Improvement followed initial discontinuation of the phenytoin, but near-fatal hepatic necrosis resulted from intravenous phenytoin rechallenge. A serious reaction with a 18% overall mortality, phenytoin hepatitis may closely resemble infectious mononucleosis with fever, pharyngitis, lymphadenopathy, and atypical lymphocytosis. Continued administration of phenytoin or later rechallenge may increase the severity of the reaction.
No takes yet. Share an insight, caveat, or question.
Brown et al. (1986) studied this question.