Review of Viral Encephalitis Cases Seen at a Tertiary Care Center in Turkey: Focus on Herpes Simplex Type 1.

INTRODUCTION The objective of this study was to determine the incidence of herpes simplex encephalitis (HSE), known as the most common, potentially mortal, and treatable cause of sporadic encephalitis, in a sample Turkish population. METHODS The demographic, clinical, laboratory, imaging, electrophysiology, and polymerase chain reaction (PCR) DNA results of patients examined with a pre-diagnosis of encephalitis were retrospectively examined. RESULTS A total of 68 patients were included in the study. The most common presenting symptom was altered behavior (67.6%), while temporal T2 hyperintensity was determined in the magnetic resonance imaging (MRI) of 27.9% of the patients and electroencephalography (EEG) abnormalities were determined in 66.2% of the patients. Lymphocytic pleocytosis was determined in the cerebrospinal fluid (CSF) in 35 patients. Fifty-seven patients had been diagnosed with viral encephalitis, 3 with bacterial meningitis, 3 with tuberculous meningitis, 2 with sporadic Creutzfeld-Jakob disease, 2 with acute disseminating encephalomyelitis, and 1 with Brucella encephalitis. Seven (10.2%) cases of viral encephalitis were found to be positive for herpes simplex virus (HSV) DNA by PCR. CONCLUSION Viral encephalitis is the most common cause of infectious encephalitis; however, other atypical causes should also be noted. Negative PCR results for HSV DNA should not exclude the need for antiviral therapy in patients with a strong pre-diagnosis of HSE because diagnostic modalities, including PCR, may fail in acute settings and HSE remains the sole treatable cause of infectious encephalitis.