Herpes simplex reactivation following neurosurgery: case report and review of the literature

A rare case of herpes simplex virus encephalitis from viral reactivation following surgically treated traumatic brain injury

OBJECTIVE

Herpes simplex virus encephalitis (HSVE) is associated with significant morbidity and mortality. Here, we present the occurrence of HSVE in a 36-year-old immunocompetent patient following craniotomy for a traumatic acute subdural hematoma (ASDH).

METHODS

Imaging after four days of progressive headache following a fall with head-strike demonstrated a 1 cm thick left holohemispheric ASDH with significant cerebral compression, edema, and 8 mm of left-to-right midline shift, and an emergent craniotomy and ASDH evacuation were performed, with additional treatment needed for reaccumulation. Postoperatively, the patient developed a worsening leukocytosis, became febrile, and was hypotensive requiring vasopressor support.

RESULTS

Despite empiric antibiotics, the patient remained persistently febrile with significant leukocytosis. Repeat head CT showed a new left insular hypodensity and a subsequent viral encephalitis panel was positive for HSV-1. The patient was then started on intravenous acyclovir, with progressive neurological exam improvement. Of note, the patient was noted to have a positive serum HSV-1 IgG antibody titer, indicative of prior infection.

CONCLUSIONS

Given the known systemic immunosuppression in brain injury and the high prevalence of HSV seropositivity, clinicians should consider the possibility of HSVE from HSV reactivation in TBI patients with persistent fever, leukocytosis, and/or neurological deficits without an obvious etiology.

State of the Art: Acute Encephalitis

Encephalitis is a devastating neurologic disease often complicated by prolonged neurologic deficits. Best practices for the management of adult patients include universal testing for a core group of etiologies, including herpes simplex virus (HSV)-1, varicella zoster virus (VZV), enteroviruses, West Nile virus, and anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibody encephalitis. Empiric acyclovir therapy should be started at presentation and in selected cases continued until a second HSV-1 polymerase chain reaction test is negative. Acyclovir dose can be increased for VZV encephalitis. Supportive care is necessary for other viral etiologies. Patients in whom no cause for encephalitis is identified represent a particular challenge. Management includes repeat brain magnetic resonance imaging, imaging for occult malignancy, and empiric immunomodulatory treatment for autoimmune conditions. Next-generation sequencing (NGS) or brain biopsy should be considered. The rapid pace of discovery regarding autoimmune encephalitis and the development of advanced molecular tests such as NGS have improved diagnosis and outcomes. Research priorities include development of novel therapeutics.

Understanding Herpes Simplex Virus Type 1 Versus Herpes Simplex Virus Type 2 Encephalitis After Neurosurgery: A Case Series and Literature Review

Abstract Background: Herpes simplex virus encephalitis (HSVE) is a rare post-operative infection that can be fatal if treatment is delayed. Herpes simplex virus type 1 (HSV-1) is a more common cause of encephalitis than herpes simplex virus type 2 (HSV-2), however, a significant overlap exists. The goal of this project was to understand the frequency and trend of HSVE after neurosurgery through a case series at our institution and in the literature with a focus on comparing HSV-1 versus HSV-2. Patients and Methods: A literature review of all published cases and case series of HSVE after neurosurgery was performed. Descriptive statistics comparing HSV-1 and HSV-2 encephalitis were computed. Data on demographics, symptoms, surgery, treatment, immunosuppression, imaging findings, steroids, and mortality were collected. Results: We identified 55 total cases of HSVE post-neurosurgery. These included 28 cases of HSV-1, 10 cases of HSV-2, and 17 cases of HSV-unspecified encephalitis. There were no differences in age, gender, symptoms, surgery, or latency between surgery and symptom onset between HSV-1 and HSV-2. Mortality was higher with HSV-1 versus HSV-2 although not statistically significant. The primary surgical indication varied substantially between HSV-1 and HSV-2. Conclusions: Herpes simplex virus encephalitis is often overlooked in the setting of encephalitis after surgery. A high index of suspicion is needed to prevent a delay in treatment.

Herpes simplex encephalitis in a patient abusing morphine: a case report from Nepal

Herpes simplex encephalitis results from either primary infection with the herpes simplex virus (HSV) or reactivation of latent HSV residing within the nuclei of sensory neurons. Opioid's administration is known to reactivate HSV infection.

Case presentation

We report a 46-year-old male who was in a rehabilitation center for 17 days for abusing morphine for 2 years.

Discussion

Chronic morphine use weakens immune system thereby, making body prone for development of infection. Opioids may reactivate HSV infection because of their immunosuppressive function.

Conclusion

Herpes simplex encephalitis is a potentially fatal condition but can be treated with early diagnosis and intervention.

Small molecule RAF265 as an antiviral therapy acts against HSV-1 by regulating cytoskeleton rearrangement and cellular translation machinery

Host-targeting antivirals (HTAs) have received increasing attention for their potential as broad-spectrum antivirals that pose relatively low risk of developing drug resistance. The repurposing of pharmaceutical drugs for use as antivirals is emerging as a cost- and time- efficient approach to developing HTAs for the treatment of a variety of viral infections. In this study, we used a virus titer method to screen 30 small molecules for antiviral activity against Herpes simplex virus-1 (HSV-1). We found that the small molecule RAF265, an anticancer drug that has been shown to be a potent inhibitor of B-RAF V600E, reduced viral loads of HSV-1 by 4 orders of magnitude in Vero cells and reduced virus proliferation in vivo. RAF265 mediated cytoskeleton rearrangement and targeted the host cell's translation machinery, which suggests that the antiviral activity of RAF265 may be attributed to a dual inhibition strategy. This study offers a starting point for further advances toward clinical development of antivirals against HSV-1.

[Reactivation of latent viruses in Neurology]

After establishing latent infection, some viruses can be reactivated by the alteration of host immunological conditions. First, we reviewed viruses that can cause neuronal damage by reactivation. Then we focused on the herpes simplex virus (HSV). The reactivation leads to neuronal damages through two possible mechanisms; "reactivation of a latent herpes virus" by which viruses can cause direct virus neurotoxicity, and "post-infectious immune inflammatory response" by which a focal reactivation of HSV leads to an inflammatory reaction. The former is radiologically characterized by cortical lesions, the latter is characterized by subcortical white matter lesions. We experienced a female, who underwent the right posterior quadrantectomy and then developed recurrent herpes encephalitis caused by herpes simplex reactivation, which pathologically demonstrated inflammation in the white matter, suggesting a post-infectious immune inflammatory response. The patient was successfully treated with immunosuppressants. The reactivation of the HSV is extremely rare in Japan. Neurologists should recognize this condition because this disorder will increase as epilepsy surgery gains more popularity.

Clinical features of herpes simplex virus reactivation after microvascular decompression for trigeminal neuralgia: Experience of 200 patients and a literature review

Background:

Herpes simplex virus (HSV) reactivation occasionally develops in the early postoperative period after microvascular decompression (MVD) for trigeminal neuralgia (TN). Therefore, the present study investigated the clinical features of this phenomenon.

Methods:

The study cohort comprised 200 patients with 125 women aged between 17 and 90 years (median age, 66 years) who underwent MVD for TN between January 2010 and December 2020. Characteristics were compared between patients with and without HSV reactivation and clinical features were analyzed.

Results:

Twenty patients had HSV reactivation: herpes labialis in 18 and herpes zoster (final diagnosis) in 2. A multivariate analysis revealed independent correlations between postoperative HV reactivation and a previous history of herpes labialis (odds ratios [OR]: 6.32, P = 0.0003) and reoperation for recurrent or persistent pain (OR: 5.06, P = 0.0211). No significant differences were observed in pain relief, postoperative facial numbness, or Barrow Neurological Institute Pain Intensity/Facial Numbness Scores in the past follow-up between patients with and without HSV reactivation. HSV reactivation manifested at a median of the 4^th postoperative day (1–10 days) and its location was not related to the preoperative distribution of facial pain. All patients were treated with local acyclovir and were completely cured within 1–2 weeks.

Conclusion:

HSV reactivation occurred in 10% of patients after MVD including 1% of herpes zoster. A previous history of herpes labialis and reoperation was identified as risk factors for reactivation. Symptoms were completely cured by antiviral drugs within 1–2 weeks. It is important to note that cases of herpes zoster may be confused with cases of HSV after MVD.

Herpes Simplex Virus Meningoencephalitis Following Pulse-Dose Methylprednisolone: A Case Report and Literature Review

Patient: Male, 76-year-old

Final Diagnosis: Herpes simplex virus type 1 (HSV-1) encephalitis

Symptoms: Encephalopathy

Medication: —

Clinical Procedure: Lumbar puncture

Specialty: Critical Care Medicine

Acute HSV and anti-NMDA encephalitis occurring as a neurosurgical complication

We present a 24-year-old man with a 2-year history of progressive right-sided monocular vision loss with no other symptoms. An MRI showed a meningioma compressing the right optic nerve and the cavernous sinus. The tumour was partially resected. Eight days after discharge the patient was admitted with fever, a severe stabbing headache, insomnia, nausea and vomiting. A FilmArray panel and a cerebral biopsy were performed which were positive for herpes simplex virus 1 (HSV-1). An MRI of the brain showed asymmetric bilateral lesions in the frontobasal region with predominance of the right side. Acyclovir was started and continued until completing 21 days. A month after discharge, he started experiencing insomnia, trichotillomania, limb tremor, persistence of abulia, apathy and emotional lability. An HSV-1 encephalitis relapse was suspected, acyclovir and foscarnet were started. Due to the poor response to antiviral therapy CSF was tested, which was positive for anti-NMDA receptor encephalitis. A treatment course of intravenous immunoglobulin was started with a favourable outcome.

Herpes simplex virus type 1 infection leads to neurodevelopmental disorder-associated neuropathological changes

Neonatal herpes simplex virus type 1 (HSV-1) infections contribute to various neurodevelopmental disabilities and the subsequent long-term neurological sequelae into the adulthood. However, further understanding of fetal brain development and the potential neuropathological effects of the HSV-1 infection are hampered by the limitations of existing neurodevelopmental models due to the dramatic differences between humans and other mammalians. Here we generated in vitro neurodevelopmental disorder models including human induced pluripotent stem cell (hiPSC)-based monolayer neuronal differentiation, three-dimensional (3D) neuroepithelial bud, and 3D cerebral organoid to study fetal brain development and the potential neuropathological effects induced by the HSV-1 infections. Our results revealed that the HSV-1-infected neural stem cells (NSCs) exhibited impaired neural differentiation. HSV-1 infection led to dysregulated neurogenesis in the fetal neurodevelopment. The HSV-1-infected brain organoids modelled the pathological features of the neurodevelopmental disorders in the human fetal brain, including the impaired neuronal differentiation, and the dysregulated cortical layer and brain regionalization. Furthermore, the 3D cerebral organoid model showed that HSV-1 infection promoted the abnormal microglial activation, accompanied by the induction of inflammatory factors, such as TNF-α, IL-6, IL-10, and IL-4. Overall, our in vitro neurodevelopmental disorder models reconstituted the neuropathological features associated with HSV-1 infection in human fetal brain development, providing the causal relationships that link HSV biology with the neurodevelopmental disorder pathogen hypothesis.

HSV-1 is one of the most prevalent human pathogens that can spread into the fetal central nervous system by maternal-fetal transmission, and thus resulting in long-term neurological sequelae in adult, including cognitive dysfunction and learning disabilities. However, there is a very limited progress in understanding the role of HSV-1 on human fetal brain development due to limited access to fetal human brain tissue as well as the limitations of existing neurodevelopmental and infection models. Here, we generated the in vitro neurodevelopmental disorder models including hiPSC-based monolayer neuronal differentiation, three-dimensional (3D) neuroepithelial bud, and 3D cerebral organoid to study the neurodevelopmental disorder-associated neuropathological changes with HSV-1 infection in human fetal brain development. Our results revealed that HSV-1 infection led to impaired neural differentiation and dysregulated neurogenesis in the fetal neurodevelopment. Additionally, HSV-1 infection impaired neuronal differentiation and dysregulated brain regionalization in our cerebral organoid model. Furthermore, the cerebral organoid model showed that HSV-1 infection led to the abnormal microglial proliferation and activation, accompanied by the induction of inflammatory factors including TNF-α, IL-6, IL-10, and IL-4. Taken together, our study provides novel evidence that HSV-1 infection impaired human brain development and contributed to neurodevelopmental disorder pathogen hypothesis, and would have implications for raising the therapeutic opportunities for targeting of viral reservoirs relevant to neurodevelopmental disorder.