Herpes simplex encephalitis following ChAdOx1 nCoV-19 vaccination: a case report and review of the literature.

BACKGROUND: Ever since the administration of early doses of COVID-19 vaccines, instances of adverse effects have been reported. Viral infections, specifically herpes simplex reinfection and coinfections, have been reported following administration of different types of vaccines. To our knowledge, there have not been any reports of herpes simplex encephalitis following administration of any type of COVID-19 vaccine to date. CASE PRESENTATION: In this article intends to report a case of herpes simplex encephalitis in a 27-year-old male patient who was vaccinated with the ChAdOx1 nCoV-19 vaccine. CONCLUSIONS: Our study suggests a possible but very rare side effect of ChAdOx1 nCoV-19 vaccine, which requires immediate medical attention and can lead to devastating consequences if left undiagnosed and untreated.

Fas/FasL Contributes to HSV-1 Brain Infection and Neuroinflammation.

The Fas/FasL pathway plays a key role in immune homeostasis and immune surveillance. In the central nervous system (CNS) Fas/FasL is involved in axonal outgrowth and adult neurogenesis. However, little is known about the role of the Fas/FasL pathway in herpes encephalitis. In this study, we used a neuropathogenic clinical strain of herpes simplex virus type 1 (HSV-1) to explore infection-induced inflammation and immune responses in the mouse brain and the role of Fas/FasL in antiviral CNS immunity. HSV-1 CNS infection induced the infiltration of Fas- FasL-bearing monocytes and T cells in the brain and also to an up-regulation of Fas and FasL expression on resident astrocytes and microglia within infected sites. Upon infection, Fas- and FasL-deficient mice (lpr and gld) were partially protected from encephalitis with a decreased morbidity and mortality compared to WT mice. Fas/FasL deficiency promoted cell-mediated immunity within the CNS. Fas receptor stimulation abrogated HSV-1 induced activation and inflammatory reactions in microglia from WT mice, while lack of Fas or FasL led to a more pronounced activation of monocytes and microglia and also to an enhanced differentiation of these cells into a pro-inflammatory M1 phenotype. Furthermore, the specific immune system was more efficient in Fas- and FasL-deficient mice with significantly higher numbers of infiltrating HSV-1-specific cytotoxic T cells in the brain. Our data indicate that the Fas/FasL pathway leads to excessive neuroinflammation during HSV-1 infection, which is associated with a diminished anti-viral response and an excessive neuroinflammation.

Travel-associated neurological disease terminated in a postmortem diagnosed atypical HSV-1 encephalitis after high-dose steroid therapy - a case report.

BACKGROUND: Human encephalitis can originate from a variety of different aetiologies, of which infection is the most common one. The diagnostic work-up is specifically challenging in patients with travel history since a broader spectrum of unfamiliar additional infectious agents, e. g. tropical disease pathogens, needs to be considered. Here we present a case of encephalitis of unclear aetiology in a female traveller returning from Africa, who in addition developed an atypical herpes simplex virus (HSV) encephalitis in close temporal relation with high-dose steroid treatment. CASE PRESENTATION: A previously healthy 48-year-old female presented with confusion syndrome and impaired vigilance which had developed during a six-day trip to The Gambia. The condition rapidly worsened to a comatose state. Extensive search for infectious agents including a variety of tropical disease pathogens was unsuccessful. As encephalitic signs persisted despite of calculated antimicrobial and antiviral therapy, high-dose corticosteroids were applied intravenously based on the working diagnosis of an autoimmune encephalitis. The treatment did, however, not improve the patient's condition. Four days later, bihemispheric signal amplification in the insular and frontobasal cortex was observed on magnetic resonance imaging (MRI). The intracranial pressure rapidly increased and could not be controlled by conservative treatment. The patient died due to tonsillar herniation 21 days after onset of symptoms. Histological examination of postmortem brain tissue demonstrated a generalized lymphocytic meningoencephalitis. Immunohistochemical reactions against HSV-1/2 indicated an atypical manifestation of herpesviral encephalitis in brain tissue. Moreover, HSV-1 DNA was detected by a next-generation sequencing (NGS) metagenomics approach. Retrospective analysis of cerebrospinal fluid (CSF) and serum samples revealed HSV-1 DNA only in specimens one day ante mortem. CONCLUSIONS: This case shows that standard high-dose steroid therapy can contribute to or possibly even trigger fulminant cerebral HSV reactivation in a critically ill patient. Thus, even if extensive laboratory diagnostics including wide-ranging search for infectious pathogens has been performed before and remained without results, continuous re-evaluation of potential differential diagnoses especially regarding opportunistic infections or reactivation of latent infections is of utmost importance, particularly if new symptoms occur.

Herpes Simplex Virus 1 encephalitis with normal cerebrospinal fluid after brain radiotherapy in a patient with glioblastoma. A case report and review of literature.

Herpes simplex virus encephalitis (HSE) is the most common cause of letal encephalitis and its prevalence appears higher among oncologic patients who undergo brain radiotherapy (RT). We describe a case of 76-year-old woman with glioblastoma multiforme (GBM) who developed HSE shortly after brain RT. Cerebrospinal fluid analysis (CSF) was normal and the diagnosis was driven by brain MRI and EEG. Prompt introduction of antiviral therapy improved the clinical picture. We highlight the importance of EEG and brain MRI for the diagnosis and suggest the possibility of antiviral profilaxys in oncologic patients who undergo brain RT.

Herpes simplex encephalitis and pseudotumour cerebri due to isotretinoin.

Isotretinoin can have significant adverse reactions on multiple systems. We report a unique case of pseudotumour cerebri and herpes encephalitis resulting due to isotretinoin. A 19-year-old female patient was admitted to our clinic, presenting with headache, nausea, vomiting and fever since three days. She had used isotretinoin for the last two months. The patient's neurological examination revealed the presence of neck stiffnes and a body temperature of 39,0◦C. MRI showed high signal localized to the temporal lobe and insula on the right and widened cerebrospinal fluid signal intensity on either side of the optic nerve. Electroencephalogram sharp and wave paroxysms on the right temporo-parietal region. Lumbar puncture showed an opening pressure of 320 mm H2O. The cerebrospinal fluid displayed the presence of 4-5 lymphocytes. On these grounds, the diagnosis of pseudotumour cerebri and herpes encephalitis was made. It is thus suggested that the physicians must keep in mind that pseudotumour cerebri and herpes encephalitis are possible adverse effects of isotretinoin.

[A 64-year-old male with recurrence of herpes simplex encephalitis after suffering from severe pneumonia and sepsis].

The case is a 64-year-old male who had a past history of herpes simplex virus encephalitis (HSE) two years prior to his admission. He was admitted to our hospital due to severe pneumonia and sepsis. Several days later, he developed HSE again. It has been known that immunosuppressive state called immune paralysis occurs in the patient with sepsis due to the amplification of anti-inflammatory responses after the initial hyper-inflammatory phase, which increases the susceptibility to various latent viruses including herpes simplex virus. In the present case, we consider that the severe infection may trigger the recurrence of HSE through the viral reactivation due to immune paralysis. When we see a patient suffering from severe infection who had a past history of HSE, we should keep in mind that such a patient may have a risk of the recurrence of HSE.

Viral Meningitis and Encephalitis.

PURPOSE OF REVIEW: This article discusses meningitis and encephalitis infections caused by viruses, excluding herpes family and human immunodeficiency virus (HIV). RECENT FINDINGS: The viral infections of the nervous system detailed in this article have no specific treatment other than supportive care. However, many of the viruses discussed are highly preventable by vaccination, proper skin protection against transmitting vectors, and postexposure prophylaxis. SUMMARY: While meningitis and encephalitis caused by viruses may have some clinical overlap, the management and outcomes can be highly disparate, making distinction between the two imperative. Furthermore, despite their relative rarity in terms of clinical disease, many of the viral infections discussed herein are highly preventable. Given the morbidity and mortality attached to such infections, provider and patient education are the best approach available to prevent these potentially devastating illnesses.

Herpes simplex virus encephalitis temporally associated with dimethyl fumarate-induced lymphopenia in a multiple sclerosis patient.

BACKGROUND: Dimethyl fumarate (DMF) is approved as first line therapy for relapsing-remitting multiple sclerosis (RRMS). In some (3%) patients, DMF induces a marked lymphopenia. Herpes simplex encephalitis (HSE) may occur in lymphopenic subjects under treatment with immune-suppressive drugs. CASE PRESENTATION: We report a case of a 39-year-old female patient with RRMS that developed HSE temporally associated with a marked and sudden drop in lymphocyte count, from 1200/µl to 600/µl, in the peripheral blood. HSE DNA was demonstrated in the cerebrospinal fluid. HSE had the features that characterize HSE occurring in immunosuppressed subjects, i.e. less prominent CSF pleocytosis, bilateral and mainly cortical involvement and less extensive tissue necrosis. Antiviral therapy determined a progressive, although incomplete, improvement. Three months later the patient presented only a mild short-term memory deficit and sporadic episodes of inappropriate emotionality. Lymphocyte count returned to normal values (1120/µl) after DMF discontinuation. CONCLUSION: Our case of HSE in a lymphopenic DMF-treated RRMS patient, points out the necessity of further studies on DMF-related lymphopenia, especially whether it implies an impaired immunity against viruses.

Insights into the pathogenesis of herpes simplex encephalitis from mouse models.

A majority of the world population is infected with herpes simplex viruses (HSV; human herpesvirus types 1 and 2). These viruses, perhaps best known for their manifestation in the genital or oral mucosa, can also cause herpes simplex encephalitis, a severe and often fatal disease of the central nervous system. Antiviral therapies for HSV are only partially effective since the virus can establish latent infections in neurons, and severe pathological sequelae in the brain are common. A better understanding of disease pathogenesis is required to develop new strategies against herpes simplex encephalitis, including the precise viral and host genetic determinants that promote virus invasion into the central nervous system and its associated immunopathology. Here we review the current understanding of herpes simplex encephalitis from the host genome perspective, which has been illuminated by groundbreaking work on rare herpes simplex encephalitis patients together with mechanistic insight from single-gene mouse models of disease. A complex picture has emerged, whereby innate type I interferon-mediated antiviral signaling is a central pathway to control viral replication, and the regulation of immunopathology and the balance between apoptosis and autophagy are critical to disease severity in the central nervous system. The lessons learned from mouse studies inform us on fundamental defense mechanisms at the interface of host-pathogen interactions within the central nervous system, as well as possible rationales for intervention against infections from severe neuropathogenic viruses.

A Case of Herpes Simplex Virus Type 1 (HSV-1) Encephalitis as a Possible Complication of Cosmetic Nasal Dermal Filler Injection.

BACKGROUND Dermal fillers are increasingly used for medical and aesthetic purposes in clinical practice. Common complications following filler injections include bruising, itching, infections, allergic reactions, and tissue necrosis. This case is the first report of Herpes simplex virus type 1 (HSV-1) encephalitis as a possible complication of dermal filler injection. CASE REPORT A 27-year-old woman with no past medical history presented with altered mental state, headaches, and seizures. She had a nasal dermal filler injection for aesthetic purpose five weeks before her acute presentation. A diagnosis of HSV-1 encephalitis was made based on brain imaging with computed tomography and magnetic resonance imaging (MRI) findings that showed bilateral frontotemporal lobe hyperintensity. Analysis of her cerebrospinal fluid (CSF) confirmed the presence of HSV-1 DNA. Despite anti-viral treatment with acyclovir, she developed postencephalitic syndrome. CONCLUSIONS This case report highlights the possibility that among the complications of the use of cosmetic dermal fillers, the transmission of HSV-1 and the development of HSV-1 encephalitis should be recognized.

Delayed Recurrence of Herpes Simplex Virus Infection in the Central Nervous System After Neonatal Infection and Completion of Six Months of Suppressive Therapy.

A 10-day-old child was treated for neonatal herpes simplex virus (HSV) central nervous system (CNS) disease with 21 days of intravenous acyclovir and 6 months of oral acyclovir. She presented 7 years later with HSV CNS disease and new lesions in her brain, illustrating the non-benign nature of delayed recurrent HSV CNS disease.

Herpes simplex type 2 encephalitis and methotrexate medication: a fortuitous or causative association in a patient with spondyloarthritis?

It is unclear whether immunosuppression is a risk factor for herpes encephalitis. Herein, we describe a rare case of herpes simplex virus type 2 encephalitis in a patient treated with low-dose methotrexate for HLA-B27-associated spondyloarthritis. The patient was successfully treated with acyclovir but presented sequelae of encephalitis. Here we discuss the possible role of low-dose methotrexate therapy as a risk factor of neurological herpes reactivation and severe disease. The host-related and viral risk factors are also addressed.

Acyclovir resistance in herpes simplex virus type I encephalitis: a case report.

Acyclovir resistance is rarely seen in herpes simplex virus (HSV) type I encephalitis. Prevalence rates vary between 0.5 % in immunocompetent patients (Christophers et al. 1998; Fife et al. 1994) and 3.5-10 % in immunocompromised patients (Stranska et al. 2005). We report a 45-year-old, immunocompetent (negative HIV antigen/antibody testing), female patient, without previous illness who developed-after a febrile prodromal stage-aphasia and psychomotor slowing. Cerebral magnetic resonance imaging (cMRI) showed right temporal and insular T2-hyperintense lesions with spreading to the contralateral temporal lobe. Cerebrospinal fluid (CSF) analysis yielded lymphocytic pleocytosis and elevated protein level. Polymerase chain reaction testing for HSV type I showed a positive result in repeat lumbar puncture. HSV type I encephalitis was diagnosed and intravenous acyclovir treatment was initiated (750 mg t.i.d.). Acyclovir treatment was intensified to 1000 mg t.i.d., due to clinical deterioration, ongoing pleocytosis and progression on cMRI 5 days after initiation of antiviral therapy. In parallel, acyclovir resistance testing showed mutation of thymidine kinase gene at position A156V prompting foscarnet therapy (60 mg t.i.d.). Patient's condition improved dramatically over 2 weeks. Acyclovir resistance is rare but should be considered in case of clinical worsening of patient's condition. To our knowledge, this is the first report of acyclovir resistance in HSV type I encephalitis of an immunocompetent and previously healthy patient in Austria.

HIV positive patient with HSV-2 encephalitis: case report.

Incidence of brain infections in Human Immunodeficiency Virus (HIV) positive patients is reduced after the availability of current high active antiretroviral therapy (HAART). Herpes Simplex Virus type 2 (HSV-2) is an infrequent cause of encephalitis in HIV patients despite it is frequently involved in sexual transmitted infections. Here, we report a case of HSV-2 encephalitis occurring in a patient without full suppression of HIV replication within the brain. A 38 year-old HIV infected man was admitted to our department because of recurrent generalized seizure and fever during the previous 24 hours. Eight months before our observation the patient was switched from a protease inhibitor based regimen to a rilpivirine-based regimen without any evidence of HIV-RNA replication in the plasma. When the patient was admitted in our hospital, he was febrile and moderately confused, no deficit of cranial nerves was reported, motility was conserved, but he was unable to walk. Laboratory examinations performed at admission demonstrated an increase of cerebrospinal fluid (CSF) protein and cells with lymphocyte prevalence, and normal CSF glucose. HSV-2-DNA and HIV-RNA were present within CSF at admission. Nuclear Magnetic Resonance imaging of the brain revealed lesions of the medial part of both temporal lobes including hippocampus without any sign of bleeding. A 21-day course of acyclovir therapy was administered with consistent improvement of clinical findings and disappearance of HSV-2-DNA within CSF. After the episode, HAART was switched to a regimen with high CSF penetrability containing abacavir, lamivudine, darunavir and ritonavir. Twelve months after HSV-2 encephalitis neurologic evaluation was normal, but symptoms of depression were reported, HIV-RNA remained undetectable both in the plasma and CSF, and CD4+ lymphocytes were above 500/µL. No opportunistic infection was reported. Patients switched to regimen well tolerated such those containing rilpivirine, that have poor drug concentration within CSF could be considered at risk for opportunistic infection of the brain. Further larger investigation needs to confirm this finding.

Herpes simplex encephalitis without cerebrospinal fluid pleocytosis in a patient with bullous pemphigoid: a case report.

A 78-year-old woman was diagnosed with bullous pemphigoid 2 months ago, and she had been treated with steroid and plasmapheresis. She developed sudden fever, vomiting, disorientation, and abnormal behavior. Diffusion weighted images and fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) images showed high-intensity signals in the right temporal lobe hippocampus and right insular cortex. Cerebrospinal fluid (CSF) examination showed normal cell count (4/mm(3)), but was positive for HSV1-DNA by PCR. She was diagnosed with herpes simplex encephalitis (HSE), and acyclovir was started on the first day of admission. She had complete recovery, and was discharged. She didn't show CSF pleocytosis throughout her course of HSE. No CSF pleocytosis could be due probably to her immunosuppressed state under the steroid therapy for bullous pemphigoid. Because the morbidity and mortality of HSE is drastically reduced by early antiviral treatment, it is important to accelerate the diagnosis and treatment of HSE, especially in immunosuppressed or immunocompromised hosts.

Herpes Simplex Type 2 Encephalitis After Craniotomy: Case Report and Literature Review.

BACKGROUND: Herpes simplex encephalitis (HSE) after neurosurgical procedures is extremely uncommon, and the few published case reports mainly described herpes simplex virus type 1 (HSV-1) as being culpable. We present a rare case of HSV-2 encephalitis after craniotomy and describe its pathophysiology and optimal management. CASE DESCRIPTION: A 70-year-old woman underwent an elective resection of a recurrent left sphenoid wing meningioma and clipping of a left middle cerebral artery aneurysm, the latter having been found incidentally. She returned to our department with clinical findings suggestive of meningitis 12 days after the operation. Her lack of response to empiric antibiotic treatment, taken together with the lymphocyte-predominant initial cerebrospinal fluid obtained by lumbar puncture and the electroencephalographic indications of encephalopathy, led to the suspicion of a diagnosis of HSE, which was later confirmed by a polymerase chain reaction test positive for HSV-2. The patient was then successfully treated with intravenous acyclovir for 2 weeks followed by another week of oral acyclovir treatment before being discharged. CONCLUSIONS: The present case stresses the importance of recognizing the relatively rare entity of HSE after craniotomy. Timely correct diagnosis will expedite the initiation of appropriate treatment.

A case of herpes simplex-associated encephalitis after brain irradiation for lung cancer metastases.

BACKGROUND: Encephalitis caused by Herpes Simplex Virus-1 is a devastating disease with high mortality and disability rates despite adequate treatment. No clear risk factors have been identified although iatrogenic immunosuppression has been suggested, among others. CASE REPORT: A 59-year-old male smoker was diagnosed with metastatic lung adenocarcinoma and was treated with brain and spinal irradiation. Ten days after the completion of radiotherapy and before initiating platinum-based front-line chemotherapy, he developed low grade fever and personality change. Over the next few days, high fever and refractory seizures developed and the patient was diagnosed with Herpes simplex-associated encephalitis after detection of viral DNA in the cerebrospinal fluid via polymerase chain reaction. Despite treatment with acyclovir, the patient remained comatose and died three months after the initial presentation. CONCLUSION: This case illustrates a possible association between brain irradiation and increased risk for Herpes simplex-associated encephalitis. However, the underlying mechanisms have not been elucidated.