[A 61-year-old female who suffered from herpes simplex encephalitis with expanded cerebral lesions on MRI and prolonged clinical course--the diagnostic usefulness of PCR using biopsied brain tissue specimens].

A 61-year-old female developed left hemiparesis after the onset of high fever and a consciousness disturbance. Fluid attenuated inversion recovery (FLAIR) MR imaging showed high signal intensity lesions in the right temporal lobe, cingulate gyrus, and parietal lobe. Encephalitis caused by a herpes simplex virus (HSV) infection was suspected and the administration of intravenous aciclovir was thus immediately initiated. Her consciousness disturbance rapidly became exacerbated; however, the brain lesions progressively expanded to the midbrain and left hemisphere. The addition of intravenous high-dose corticosteroids to the treatment regimen ameliorated the consciousness disturbance. Although no HSV DNA was detected by repeated PCR using cerebrospinal fluid (CSF) specimens, real time PCR using a biopsied brain tissue specimens detected HSV type 1 DNA. A pathological examination showed destruction of the grey matter and a perivascular aggregation of lymphocytes, thus suggesting a diagnosis of necrotizing viral encephalitis. Immunohistochemical analysis did not reveal the presence of the HSV antigen. Hence, in the present patient failure of PCR or a serological diagnosis using CSF specimens can be ascribed to the paucity of viral particles in the brain. We therefore concluded that real-time PCR using biopsied brain tissue specimens is a novel, sensitive method for detecting causative agents in patient with prolonged and undiagnosed encephalitis.