Fulminating encephalopathy with perivenular demyelination and vacuolar myelopathy as the initial presentation of human immunodeficiency virus infection

Objective: To study the neuropathologic features in a case involving a 22-year-old woman in whom a fulminating encephalopathy developed as the initial manifestation of human immunodeficiency virus (HIV) infection. Design: Case report. Setting: Tertiary care hospital. Patient: The patient presented with rapidly progressive mental status changes, cranial nerve abnormalities, and quadriplegia, which led to her death 5 months later. Serologic tests for HIV were initially indeterminate on Western blot analysis but were positive 1 week later. Methods: A complete autopsy, including examination of the brain and spinal cord, was performed. Paraffin-embedded sections of the brain and spinal cord were examined using standard histologic staining procedures and immunohistochemical techniques. Results: Neuropathologic examination revealed discrete foci of perivenular demyelination disseminated throughout the brain and spinal cord, as well as severe vacuolar myelopathy. Lesions typical of HIV encephalitis were not present. Human immunodeficiency virus-infected monocytes and microglia were observed in the vicinity of, but not restricted to, the perivenular demyelinating lesions. No other infectious agents were identified. Conclusions: The patient's acute encephalopathy was most likely the direct result of a widespread demyelinating process resembling acute disseminated encephalomyelitis. We suggest that the perivenular demyelination may represent an autoimmune reaction, possibly due to a nonspecific viral infection, occurring in the setting of chronic immunosuppression secondary to HIV. Although less likely, we cannot exclude the possibility that HIV could have directly triggered an autoimmune response that caused the acute disseminated encephalomyelitis-like lesions.