AIDS-ASSOCIATED PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY REVEALED BY NEW-ONSET SEIZURES

PURPOSE: TO describe the clinical features of new-onset seizures in HI V-1-infected persons with progressive multifocal leukoencephalopathy ( PML), and to discuss potential mechanisms. PATIENTS AND METHODS: Forty -nine consecutive HIV-1-infected patients with PML attended our instit utions between January 1988 and September 1993. We retrospectively ana lyzed cases with seizures as the presenting symptom of PML. RESULTS: T wenty percent of the HIV-1-infected patients with PML presented with n ew-onset seizures of various types, generalized or partial. None of th em met the criteria of the AIDS dementia complex or had a concomitant opportunistic infection. Their mean CD4 cell count was <60/mm(3). Brai n magnetic resonance imaging showed areas of increased signal intensit y on T-2-weighted images in 9 cases, and atrophy in only 1 case. Lesio ns most often involved subcortical white matter in parieto-occipital o r frontal lobes, but 2 patients had posterior fossa lesions. Image-gui ded stereotactic brain biopsies in 8 cases and postmortem examination in 2 confirmed the diagnosis of PML. Typical histological lesions were observed in all cases, and positive immunolabelling of oligodendrogli al nuclei was obtained in all cases with the polyclonal antibody direc ted against late SV40 antigens. Putative causative factors for the sei zures include demyelinated lesions adjacent to the cerebral cortex act ing as irritative foci, axonal conduction abnormalities, or disturbanc es of the neuron-glia balance. CONCLUSION: These cases illustrate that PML should be considered as a possible cause of new-onset seizures in patients with HIV-1 infection.