Human Herpesvirus 6 encephalitis in an immunocompetent pregnant patient and review of the literature

Human Herpesvirus 6A (HHV-6A) Encephalitis in an Immunocompetent Patient and Its Association With Glioblastoma: A Case Report

Human herpesvirus 6 (HHV-6) is a neurotropic virus capable of establishing latency in the central nervous system. While its reactivation is well-documented in immunocompromised individuals, its role in immunocompetent hosts remains unclear. Additionally, growing but inconclusive evidence suggests a potential association between HHV-6 and glioblastoma. We present the case of a 65-year-old immunocompetent male who developed HHV-6A-associated meningoencephalitis, followed by the diagnosis of high-grade glioblastoma within months. The patient initially presented with altered consciousness, seizures, fever, and right-sided motor deficits, leading to a diagnosis of HHV-6A meningoencephalitis confirmed by cerebrospinal fluid and plasma polymerase chain reaction. Despite clinical improvement with antiviral therapy, he developed progressive neurological symptoms two months later, and neuroimaging revealed multiple expansile lesions with significant mass effects. A stereotactic brain biopsy confirmed the diagnosis of glioblastoma, isocitrate dehydrogenase-wildtype, and the patient ultimately succumbed to the disease. The temporal association between HHV-6A infection and glioblastoma raises critical questions about its potential role in tumorigenesis. While previous studies have detected HHV-6 DNA and proteins in glioma tissues, supporting hypotheses of viral-mediated inflammation, immune modulation, and oncogenic interactions, a direct causal link remains unproven. Additionally, the patient's treatment with valganciclovir, an antiviral explored as a potential glioblastoma adjuvant therapy, prompts discussion about its possible influence on tumor progression. Further research into HHV-6's oncogenic potential may provide valuable insights into gliomagenesis and open avenues for novel therapeutic strategies, including antiviral approaches in glioblastoma management.

Diagnostic Dilemmas: A Review of Reported Cases of Human Herpesvirus 6 Encephalitis in Immunocompetent Adults

Human herpesvirus 6 (HHV-6) is associated with its presentation in the pediatric population as roseola infantum. Rarely, it is the causative agent of encephalitis, with most cases reported among the immunocompromised population due to reactivation. This review article analyzes the published records of cases labeled HHV-6 encephalitis in immunocompetent adults, aiming to understand the diagnostic methods behind each case and explore the complexities of such a diagnosis. We note significant variability in the methods used to come to a diagnosis of HHV-6 encephalitis, as well as inconsistent approaches to treatment of this condition. Given the rarity of HHV-6 encephalitis in immunocompetent adults, there are no clearly structured diagnostic guidelines for this condition in this patient population. We highlight several diagnostic methods that provide more convincing evidence of true HHV-6 encephalitis and may provide a basis for further development of guidelines for the diagnosis and treatment of this condition.

Human Herpes Virus-6 (HHV-6) infectious encephalitis in an immunocompetent adult

Human herpesvirus 6 (HHV-6) is one of the most prevalent childhood viruses. HHV-6 reactivation in allogeneic hematopoietic cell transplant recipients and solid organ transplant recipients is well described in medical literature. We present a case of HHV-6 reactivation causing encephalitis, which is rare in immunocompetent adults.

Human Herpes Virus 6-Associated Meningitis in an Immunocompetent Adult With a History of Plaque Psoriasis: A Case Report

Human herpes virus-6 (HHV-6) is a common cause of viral infection in humans, recognized for causing exanthema subitem during the first two years of life. Chronic inflammatory states in different autoimmune diseases can be associated with an immunosuppressed microenvironment. We report a case of HHV-6-associated meningitis in a patient with psoriasis. A 36-year-old man with a history of psoriasis presented with worsening bifrontal headache as well as painful oral lesions on the tongue and soft palate. Computed tomographic (CT) scan of the brain was nondiagnostic. Cerebrospinal fluid (CSF) analysis was diagnostic for HHV-6 infection and was treated with intravenous ganciclovir for two weeks. This case report highlights the emergence of HHV-6 infections in people with underlying mild immune disorders, such as psoriasis. Plaque psoriasis, such as in this patient, could be related to viral infections not typically seen among adults.

A Rare Case of Human Herpesvirus 6 Meningitis in an Immunocompetent Asian Male Presented With a Severe Intractable Headache

Human herpesvirus 6 (HHV-6) manifesting as a central nervous system (CNS) infection (especially meningoencephalitis) is reported as a primary infection in children and from reactivation in immunocompromised patients; however, it has rarely been reported in immunocompetent adults. Latent infections of the CNS can cause a myriad of clinical presentations ranging from a benign, febrile, self-resolving illness to limbic encephalitis, temporal lobe seizures, and neuropsychiatric symptoms such as behavioral disturbances and psychosis. No standard diagnostic criteria or management guidelines exist for this condition. Possible neuroimaging findings include abnormalities in the medial temporal lobe involving the hippocampus and amygdala. We hereby present a case of HHV-6 meningitis in a 48-year-old immunocompetent male presenting without encephalopathic symptoms and normal neuroimaging findings.

Is the ZIKV Congenital Syndrome and Microcephaly Due to Syndemism with Latent Virus Coinfection?

The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.

Human herpes virus-6 (HHV-6) pneumonitis and meningitis with viraemia in an immunocompetent adult patient

Human herpes virus-6 (HHV-6) infection is a common infection in the paediatric population and is increasingly reported in immunosuppressed adult patients. It has been reported as the causative agent of disease in few case reports in immunocompetent adults. We report herein an unusual case of HHV-6-associated viraemia, pneumonitis and meningitis in a patient who presented with dyspnoea, hypoxia, dry cough and headache. She was treated for atypical pneumonia with no improvement. Meningitis was suspected as headache kept worsening. HHV-6B was detected by PCR in the cerebrospinal fluid, and subsequently, in the bronchoalveolar lavage and serum samples. Studies were negative for the most common primary and secondary immunodeficiency syndromes, and serology could not be performed to differentiate virus reactivation from a primary infection. The patient was successfully treated with ganciclovir and had no residual sequelae.

Post-mortem detection of six human herpesviruses (HSV-1, HSV-2, VZV, EBV, CMV, HHV-6) in trigeminal and facial nerve ganglia by PCR

Background

Among over 100 types of Herpesviridae viruses, eight can infect humans: herpes simplex viruses (HSV-1, HSV-2), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesviruses 6, 7, and 8 (HHV-6, HHV-7, HHV-8). After initial infection, the viruses remain latent for the lifetime of the host. The aim of this study was to determine the distribution of six different herpesviruses: HSV-1, HSV-2, VZV, EBV, CMV, and HHV-6 in trigeminal and facial nerve ganglia among a random group of Polish population.

Methods

The studied group consisted of 47 individuals (40 male, seven female); mean age of 47.4 ± 16.5 years) who died of independent causes (suicide, traffic accident, and poisoning, among others). Bilateral trigeminal and facial nerve ganglia of each cadaver were collected during the autopsy. Herpesviruses were detected using multiplex polymerase chain reaction technique.

Results

Herpesviruses were found in trigeminal and/or facial ganglia in 30/47 (63.8%) of cadavers. HHV-6 was the most prevalent of the herpesviruses and was found in nearly half of cadavers (n = 22; 46.8%), followed by HSV-1 (n = 7; 14.9%), VZV (n = 4; 8.5%), EBV (n = 4; 8.5%), HSV-2 (n = 2; 4.3%), and CMV (n = 1; 2.1%). Facial nerve ganglia (n = 23; 48.9%) were more often infected than trigeminal ganglia (n = 13; 27.7%).

Discussion

The results of this study have revealed a common presence of the herpesviruses in trigeminal and facial nerve ganglia among a random group of Polish population. Furthermore, the data also demonstrate simultaneous infection of the ganglia with different herpesviruses. This study has contributed to the knowledge of prevalence and localization of herpesviruses in different structures of the nervous system.