Clinically severe Epstein-Barr virus encephalitis with mild cerebrospinal fluid abnormalities in an immunocompetent adolescent: a case report.

A 15-year-old boy developed Epstein-Barr virus (EBV) encephalitis, a rare complication of infectious mononucleosis. The severe clinical picture and the marked neuroimaging changes were in contrast with mild cerebrospinal fluid abnormalities: leukocyte count was normal and protein level was only slightly elevated. EBV DNA was detected in cerebrospinal fluid by polymerase chain reaction.