Progressive multifocal leukoencephalopathy: A retrospective study of 30 cases

We performed a retrospective review of progressive multifocal leukoencephalopathy (PML) in 30 patients, all of whom were HIV positive (1.6% of all HIV patients admitted for the study period). PML was the first AIDS illness hi 53% of patients. The median CD4 count was 30 cells/μl. Unifocal disease as determined by clinical examination occurred in 60%, by computed tomography in 50% and by magnetic resonance imaging hi 27%. Hemiparesis and cerebellar ataxia were the commonest presenting clinical syndromes (60% and 43%). Most imaging revealed low density, non-enhancing lesions without mass effect. Definitive or suggestive pathological diagnosis by light and electron microcopy and in situ hybridization was made in 80% of biopsied patients. No one pathological method was definitive in all cases. Nineteen patients commenced treatment with cytosine arabinoside (ara-C). The median survival of the whole group was 4 weeks (range 1-120; mean 12.6 weeks), with four patients surviving for more than 24 weeks. A CD4 count of more than 50 cells/μl was significantly associated with improved survival (12 weeks versus 4 weeks if CD4 count was less than 50). As a whole treatment with ara-C did not significantly improve survival although there appeared to be individual exceptions.