ABSTRACT
Demonstration of the direct involvement of cranial blood vessels by varicella zoster virus (VZV) is facilitated by immunohistochemistry (IHC), in situ hybridization (ISH) and polymerase chain reaction (PCR) techniques. The extent to which an inflammatory vasculitis serves as the pathogenic mechanism for VZV encephalomyelitis (VZVE) is still, however, debated. Most VZVE patients are immunocompromised and show little inflammation, either pre-mortem in cerebrospinal fluid (CSF) or at autopsy. We describe an HIV-positive patient with a moderately depressed CD4 count (304) who presented with massively elevated CSF protein (1800 mg/dl), bloody CSF and pleocytosis (1300 white blood cells (WBC)/mm3). His CSF was positive for VZV DNA by PCR. He was treated with acyclovir and foscarnet, but died. At autopsy, an unusually widespread, inflammatory, transmural vasculitis caused by VZV affected meningeal vessels at virtually all brain stem and spinal cord levels, causing multiple subpial hemorrhages and necrosis. Virus DNA in multiple areas of brain, brainstem and spinal cord was readily revealed by PCR, but not by the presence of viral inclusions, IHC or ISH. This case, with a clinically confusing presentation for VZVE, illustrates the extensive, albeit infrequent, degree of necrotizing vasculitis and CSF abnormalities that VZV is capable of producing. Antiviral therapy may have inhibited VZV genome replication and subsequent antigen production, resulting in negative ISH and IHC studies, but generated increased VZV genomic fragments that were detectable by the more sensitive PCR technique.
