Research Article: Analysis of Metagenomic Next-Generation Sequencing (mNGS) in the Diagnosis of Herpes Simplex Virus (HSV) Encephalitis with Normal Cerebrospinal Fluid (CSF)
Abstract:
Herpes simplex encephalitis (HSE) is an acute infectious disease of the central nervous system caused by herpes simplex virus (HSV), which mainly invades the temporal lobe, frontal lobe and limbic system, causing bleeding and necrotizing encephalitis., HSV is a neurophilic double-stranded DNA virus that is classified into two distinct types: oral herpes (HSV-) and genital herpes (HSV-). Approximately three-quarters of HSE patients are caused by HSV-. HSE is recognized by its temporal and frontal lobe involvement, as well as elevated levels of white blood cells and protein in the cerebrospinal fluid, and discoloration in the form of red blood cells and yellowing. Early detection of frontotemporal lobar edema can be accomplished using magnetic resonance imaging (MRI), which may also reveal brain swelling. The DNA PCR for HSV of the CSF is considered the standard gold test with a sensitivity of –% and specificity of –%. Diagnosing HSE becomes easier when typical symptoms are accompanied by PCR results. However, many patients with atypical HSE may have normal cerebrospinal fluid leukocyte counts in clinical practice, making them susceptible to misdiagnosis as cerebral infarction or intracranial space-occupying lesions. Although viral isolation and PCR testing are considered the “gold standard” for HSE diagnosis, the limitations of these methods, such as the time-consuming nature of viral isolation and its low detection rate, and the limited ability of PCR testing to detect nucleic acid fragments, have restricted their clinical application. Hence, diagnosing atypical HSE can be a challenging task. Studies indicate that untreated HSE patients have a high mortality rate of up to %, but if treatment is initiated within four days of onset, the mortality rate can be reduced to %. Thus, early diagnosis and treatment of HSE are crucial, as misdiagnosis or missed diagnosis can have serious consequences for patients. The increasing use of metagenomic next-generation sequencing (mNGS) in infectious disease diagnosis, due to its advantages, is becoming more widespread in clinical practice., Since Guan first reported the research on mNGS in HSV and HSV in , mNGS has played a more critical role in diagnosing HSE. It is reported that a few HSE patients have no abnormal changes in CSF. In , Rawal et al presented a case of HSVE in which the CSF analysis was standard, but the CSF PCR was positive for HSV. In , Jakob et al reported five cases of HSVE in immunosuppressed patients who had received whole-brain irradiation for malignoma in Germany, where the CSF was normal. In , Avkan Oguz et al documented the same phenomenon in two immunocompetent patients in Turkey. Nonetheless, such patients always exhibit an absence of typical clinical features and MRI findings of HSE, which presents a significant challenge for the early and definitive clinical diagnosis of the condition.
Introduction:
Herpes simplex encephalitis (HSE) is an acute infectious disease of the central nervous system caused by herpes simplex virus (HSV), which mainly invades the temporal lobe, frontal lobe and limbic system, causing bleeding and necrotizing encephalitis. , HSV is a neurophilic double-stranded DNA virus that is classified into two distinct types: oral herpes (HSV-) and genital herpes (HSV-). Approximately three-quarters of HSE patients are caused by HSV-. HSE is recognized by its temporal and frontal lobe involvement,…
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