Review Note

Last Update: 04/01/2024 02:30 AM

Current Deck: Neurology::Neuroimmunology/NeuroID

Published

Classic MRI findings in {{c1::PML}} consist of multiple demyelinating, non-enhancing lesions with no mass effects in an immunocompromised patient.

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY (PML)

Caused by: the John Cunningham (JC) virus. Infection is acquired in childhood. About 55% to 85% of adult population is seropositive.
Opportunistic CNS infection due to reactivation of latent JC virus in tonsil, bone marrow, and spleen
Seen in immunodeficiency (5% of AIDS patients have PML when CD4 <200 cells/microliter), hematologic malignancies, and organ transplantation
Seen in patients on immunomodulatory therapy with natalizumab, rituximab, and efalizumab f. Pathogenesis: reactivation of virus, dissemination to CNS, and infection of oligodendrocytes (demyelination) and astrocytes (neuronal dysfunction)
Clinical: Cognitive decline, visual field deficits, cranial neuropathies, sensory deficits, motor deficits, speech disturbances, and ataxia progressing to dementia; headaches, extrapyramidal syndromes, and seizures are rare.
Diagnosis:

Confirmed by detecting JC virus particles or antigens in brain tissue, isolating the virus from brain, or PCR
MRI brain: confluent multifocal white-matter lesions with T2 prolongation, typically within cerebral subcortical white matter and brainstem
Pathology: oligodendrocytes contain eosinophilic intranuclear inclusions; bizarre astrocytes.