Atypical brainstem encephalitis caused by herpes simplex virus 2.

Abstract

BACKGROUND: Herpes simplex encephalitis is one of the most common and serious sporadic encephalitides of immunocompetent adults. Herpes simplex virus 2 (HSV-2) infections of the central nervous system usually manifest as subacute encephalitis, recurrent meningitis, myelitis, and forms resembling psychiatric syndromes. OBJECTIVES: To report and discuss magnetic resonance imaging (MRI) findings and clinical features in atypical brainstem encephalitis and facial palsy associated with HSV-2. SETTING: Neurology department of a tertiary referral center. PATIENT: A 37-year-old woman was admitted to the hospital with fever, diplopia, left hemiparesis, sensory change in the face and limbs, personality changes, frontal dysexecutive syndrome, and a stiff neck. Brain MRI showed multifocal high-signal intensities in the pons, midbrain, and frontal lobe white matter on T2-weighted and fluid-attenuated inversion recovery images. Cerebrospinal fluid (CSF) polymerase chain reaction (PCR) amplification analysis was positive for HSV-2. Acyclovir therapy was started, and the encephalitic symptoms disappeared with a negative conversion of HSV-2 PCR in the CSF. However, after the discontinuation of acyclovir therapy, peripheral facial palsy occurred on the left side. A possible relapse or delayed manifestation of the HSV-2 infection was suspected, and the acyclovir therapy was restarted. A complete remission was achieved 3 days after the treatment. She was discharged without any neurologic sequelae. CONCLUSIONS: We describe a patient who developed atypical encephalitis due to HSV-2 and peripheral facial palsy, which could also be related to the HSV-2. This case suggests that HSV-2 should be considered among the possible causes of atypical or brainstem encephalitis and that the PCR amplification method of the CSF can help reveal the possible cause of HSV-2.