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

The Worldwide Prevalence of Herpes Simplex Virus Encephalitis and Meningitis: A Systematic Review and Meta-Analysis

Given the relatively high frequency of central nervous system infections and considerable mor- tality and morbidity reported to be caused by herpes simplex viruses among the other viral agents, having a clear knowledge about their epidemiological profile seems necessary. This systematic review and meta-analysis aimed to determine the relative frequency and preva- lence of herpes simplex encephalitis and meningitis in patients tested for viral etiologies. A comprehensive systematic review was performed in PubMed, Scopus, and Web of Science databases, searching for studies on the prevalence and relative frequency of herpes sim- plex virus 1 and herpes simplex virus 2 encephalitis and meningitis. Seventy-one studies were included. Overall, the prevalence of herpes simplex virus encephalitis among patients tested was 8% (95% confidence interval, 6%-11%; I2 = 98%) and the prevalence of herpes simplex virus meningitis among aseptic patients tested was 4% (95% confidence interval, 3%-7%; I2 = 95%), and a significant difference was observed by region. The results of our subgroup analysis for herpes simplex virus encephalitis revealed a prevalence of 8% for pediatric patients and ado- lescents and 12% for adults. The results for herpes simplex virus meningitis showed a prevalence of 4% for pediatric patients and adolescents and 9% for adults. We observed significant differ- ences in the frequency of herpes simplex virus 1 and herpes simplex virus 2 detection rates by region. Having high rates of missed cases due to inadequate, highly sensitive paraclinical tests performed on patients with suspected viral central nervous system infection is one of the pos- sible factors. More studies are needed to detect the possible flaws in the process of diagnosis in different regions.

Prevalence and clinical manifestations of herpes simplex virus infection among suspected patients of herpes simplex encephalitis in Shiraz, Iran

Encephalitis has infectious and noninfectious etiology. Among infectious agents, viruses are the main causes of encephalitis; Herpes simplex virus (HSV) is known as the most common causative agent of viral encephalitis. In this current cross-sectional investigation, we aimed to assess the prevalence of HSV in the cerebrospinal fluid (CSF) specimens of Herpes Simplex Encephalitis (HSE) suspected patients and also determining the clinical symptoms and laboratory findings of this viral complication. Two hundred consecutive HSE suspected patients with clinical diagnosis of encephalitis were included in the study and then the presence of HSV DNA in their CSF was applied by Polymerase Chain Reaction (PCR) assay. Molecular detection of two hundred (117 males with mean age: 43 years, 83 females with mean age: 39 years) CSF samples showed that 22 (11.11%) cases were positive for HSV infection. 15(68.18%) of the positive samples were more than 50 years old, however, there was no significant correlation between age distribution, gender and HSE clinical manifestations. Fever (91%), headache (72.7%), seizer (59%), and weakness (59%) were the most common symptoms in positive patients and also mortality rate was (18.18%). CSF laboratory abnormalities of HSE cases were as follows; lymphocytic pleocytosis 19 (86.3%), leukocytosis 19 (86.3%), elevated protein level 16 (72.7%), and hypoglycorrhachia 3(13.6%). Screening of HSE suspected patients is crucial in the treatment of patients and reduce the mobility and morbidity of patients. Qualitative PCR as an available method in most developing countries could be a reliable method to monitor consecutive HSE suspected patients.

Herpes simplex virus (HSV) encephalitis in a young man: an unusual course

We present a case of cerebral venous sinus thrombosis (CVST) as a rare complication of herpes simplex virus (HSV) encephalitis. A young man with no pertinent medical history was diagnosed with HSV encephalitis. After initial treatment, he showed improvement in symptomatology until day 6 when he acutely developed new neurological deficits. An urgent MRI brain showed changes in left temporal lobe consistent with HSV encephalitis and lack of flow void in superior sagittal sinus. Subsequent magnetic resonance venography confirmed the diagnosis of superior sagittal sinus thrombosis along with thrombosis of bilateral frontoparietal cortical draining veins. Anticoagulation was immediately initiated and oral anticoagulation was continued for 1 year. He made complete recovery subsequently. Our case serves as a reminder for the treating clinicians to consider CVST in patients with HSV encephalitis who develop an unexpected new neurological deficits during early phase of appropriate treatment.