Varicella zoster virus cerebral aneurysmal vasculopathy presenting in a newly-diagnosed HIV-positive patient

Central nervous system infections produced by varicella zoster virus

PURPOSE OF REVIEW

Varicella zoster virus (VZV) causes varicella, establishes latency, then reactivates to produce herpes zoster. VZV reactivation can also cause central nervous system (CNS) disease with or without rash. Herein, we review these CNS diseases, pathogenesis, diagnosis, and treatment.

RECENT FINDINGS

The most common CNS manifestation of VZV infection is vasculopathy that presents as headache, cognitive decline, and/or focal neurological deficits. VZV vasculopathy has also been associated with cerebral amyloid angiopathy and moyamoya syndrome. Rarely, VZV will produce a meningitis, encephalitis, cerebellitis, and myelopathy. Pathogenic mechanisms include direct VZV infection of affected tissue, persistent inflammation, and/or virus-induced hypercoagulability. Diagnosis is confirmed by the temporal association of rash to disease onset, intrathecal synthesis of anti-VZV antibodies, and/or the presence of VZV DNA in CSF. Most cases respond to intravenous acyclovir with corticosteroids.

SUMMARY

VZV produces a wide spectrum of CNS disorders that may be missed as some cases do not have an associated rash or a CSF pleocytosis. Clinicians must be vigilant in including VZV in their differential diagnosis of CNS infections as VZV is a ubiquitous pathogen; importantly, VZV CNS infections are treatable with intravenous acyclovir therapy and corticosteroids.

Determinants of neurological syndromes caused by varicella zoster virus (VZV)

Varicella zoster virus (VZV) is a pathogenic human herpes virus which causes varicella as a primary infection, following which it becomes latent in peripheral autonomic, sensory, and cranial nerve ganglionic neurons from where it may reactivate after decades to cause herpes zoster. VZV reactivation may also cause a wide spectrum of neurological syndromes, in particular, acute encephalitis and vasculopathy. While there is potentially a large number of coding viral mutations that might predispose certain individuals to VZV infections, in practice, a variety of host factors are the main determinants of VZV infection, both disseminated and specifically affecting the nervous system. Host factors include increasing age with diminished cell-mediated immunity to VZV, several primary immunodeficiency syndromes, secondary immunodeficiency syndromes, and drug-induced immunosuppression. In some cases, the molecular immunological basis underlying the increased risk of VZV infections has been defined, in particular, the role of POL III mutations, but in other cases, the mechanisms have yet to be determined. The role of immunization in immunosuppressed individuals as well as its possible efficacy in preventing both generalized and CNS-specific infections will require further investigation to clarify in such patients.

Fungal aneurism of the right posterior inferior cerebellar artery (PICA)

In this case-report, the Authors show the case of a sudden death occurred in a 38-year-old woman submitted to surgical excision of a right acoustic neurinoma. At the autopsy, was detected a cerebral hemorrhage with multifocal localization by a ruptured rare fungal aneurysm of the Posterior Inferior Cerebellar Arthery (PICA). The PCR analysis, carried out on formalin-fixed paraffin-embedded tissue, identified the Aspergillus Penicillioides as the involved pathogen. We discuss the main points of infectious aneurysms, being a potential neurosurgical complication.