Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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December 18, 2014
Progressive Multifocal Leukoencephalopathy
- Progressive multifocal leukoencephalopathy (PML) is a subacute demyelinating disease with focal or multifocal neurologic deficits due to reactivation of JC virus, generally in patients with severe immunosuppression. It may lead to the development of immunereconstitution inflammatory syndrome (IRIS) in patients starting HAART.
- Clinical Presentation: Nonspecific, including headache, seizures, and focal neurologic deficit
- Diagnosis usually rests on neuroimaging and is further confirmed by cerebrospinal fluid polymerase chain reaction (PCR) for JC virus DNA
- Key Diagnostic Features
- Single or multiple asymmetric white matter lesions, often T1-hypointense, T2-hyperintense. A leading edge of diffusion restriction may be seen, which reflects active of demyelination.
- Most lesions are either periventricular or subcortical, scalloping the U-fibers.
- Occasionally, cerebellum and brain stem involvement is seen.
- Gray matter inolvement is uncommon.
- Minimal mass effect for the size of the lesions
- Often no enhancement, although sometimes marginal or punctate intralesional enhancement can be seen.
- DDx:
- Lymphoma
- New multiple sclerosis in patients being treated with monoclonal antibodies (eg, Tysabri)
- ADEM
- Rx: No known cure; HAART is helpful
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