Herpes Encephalitis: A Report of Two Cases

Herpes simplex virus (HSV) is the most common causative agent of acute, sporadic viral encephalitis. HSV encephalitis usually proceeds with focal edema, necrosis and bleeding in the temporal and frontal lobes. Acute fever and especially signs of temporal lobe involvement are typical clinical findings. It is difficult to differentiate HSV encephalitis from other viral encephalitis or other noninfectious states. The mortality rate is high in untreated patients. The most sensitive noninvasive method used in early diagnosis of HSV encephalitis is to demonstrate HSV-DNA in cerebrospinal fluid (CSF) by polimerase chain reaction (PCR). The most sensitive radiological method is magnetic resonance imaging (MRI). In this study, we present two cases diagnosed as HSV encephalitis, in our clinic in the year 2001, with characteristic MRI findings and positive results of HSV-DNA by PCR in CSF and the current literature has been reviewed. In conclusion, in cases suggesting herpes encephalitis according to the clinical, CSF and cranial MRI findings, CSF must be studied for HSV-DNA by PCR and treatment with acyclovir must be started as soon as possible. Combining MRI findings with PCR result would strongly suggest the diagnosis.