Bulbar encephalitis complicating trigeminal zoster in the acquired immune deficiency syndrome.

A 30-year-old homosexual man with the acquired immune deficiency syndrome and a recent history of zoster involving the mandibular division of the right trigeminal nerve was found at autopsy to have a predominantly demyelinating lesion restricted to the ipsilateral spinal trigeminal tract and nucleus. Cowdry A inclusions were readily apparent in the nuclei of numerous glia and isolated neurons, and inclusion-bearing cells were immunoreactive with an antiserum to the varicella zoster virus (VZV). This represents the first demonstration that zoster-associated trigeminal encephalitis is the result of brainstem invasion by VZV. The restricted topography of this lesion implicates axonal transport in its pathogenesis.