Atypical progressive multifocal leukoencephalopathy in HIV with a high CD4 count: the use of magnetic resonance imaging plus spectrometry studies

Abstract

Progressive multifocal leukoencephalopathy (PML) is still a underinvestigated central nervous system infection, often linked to HIV-related immunodeficiency. We present an unusual case report characterized by motor involvement, which occurred as the first AIDS-defining event in the absence of appreciable immunodeficiency in a patient with previously undiagnosed HIV infection, who was also assessed by a functional–metabolic magnetic resonance imaging technique (MRI–spectrometry). A 45-year-old patient had HIV infection detected after the appearance of motor abnormalities, in the absence of other signs or symptoms. No significant immunodeficiency was found (initial CD4+ lymphocyte count of 566 cells/µL), and HIV viral load was 24,000 RNA copies/mL. Combination antiretroviral therapy was started with lamivudine, abacavir and lopinavir/ritonavir, with subsequent addition of efavirenz and enfuvirtide. Elevated cerebrospinal fluid levels of JC virus (JCV) (11,668 copies/µL) and consistent neuroradiological findings at contrast-enhanced computed tomography and MRI scans confirmed a diagnosis of PML. Despite the aggressive therapeutic approach, which achieved undetectable HIV viraemia, a CD4+ count above 700 cells/µL and disappearance of JCV after 20 days, the neurological motor involvement rapidly deteriorated, yet associated cognitive impairment never occurred. Clinical and neuroradiological deterioration occurred, and our patient died five months after the diagnosis due to respiratory failure. Combined MRI–spectrometry studies performed 10 days before death included proton (1H) spectrometry, and an MRI study-calculation of water diffusion and anisotropy: through this innovative technique combining morphological and metabolic findings, multiple abnormalities involving the subtentorial white matter were detected (with multiple encephalic trunk and ponto-bulbar lesions), which usually are not part of the PML course.