Diffusion-weighted magnetic resonance is better than polymerase chain reaction for early diagnosis of herpes simplex encephalitis: a case report.

Herpes simplex virus infection of the central nervous system is still a significant cause of morbidity and often mortality. Early diagnosis is critical because treatment with the antiviral drug acyclovir dramatically decreases morbidity and mortality in children. The use of polymerase chain reaction techniques is a diagnostic procedure in herpes simplex virus infection, but negative polymerase chain reaction test results of cerebrospinal fluid herpes simplex virus can occur within the first 72 hours of illness, with subsequent test results becoming positive as in this case. Therefore, diffusion-weighted magnetic resonance may play a major role as a first and early diagnostic step.