Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
July 2017
Next Case of the Month coming August 1...
Progressive Multifocal Leukoencephalopathy (PML)
- Background:
- Opportunistic infection almost always caused by JC polyomavirus (JCV)
- Destroys oligodendrocytes, which results in demyelination in immunocompromised patients
- Associated with immunosuppression—most commonly AIDS—but also seen in patients treated with immunosuppressive monoclonal antibodies such as rituximab
- Clinical Presentation:
- Altered mental status and headache +/- focal neurologic symptoms in an immunocompromised patient
- Key Diagnostic Features:
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T2 hyperintense demyelinating plaques commonly extending to juxtacortical white matter, causing “scalloped” appearance
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Typically bilateral and asymmetric; most commonly seen in the parietoccipital region
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Very rarely can be seen in the cerebellum or brainstem (as in this case)
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No contrast enhancement or mass effect acutely
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Can see enhancement after immune reconstitution
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Can be hypometabolic on PET, although limited case reports demonstrate some conflicting conclusions
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- Differential Diagnoses:
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HIV encephalitis: can look similar or coexist, although pure HIV encephalitis tends to be less focal
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Acquired CMV: also tends to be diffuse/less focal; can see ventriculitis and retinitis
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CNS lymphoma: more mass effect and enhancement
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Toxoplasmosis: also more mass effect
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Immune reconstitution inflammatory syndrome (IRIS): can coexist with PML and change the appearance of preexisting lesions (new enhancement)
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- Treatment:
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Highly active antiretroviral therapy (HAART) improves survival
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Results in death without treatment; early recognition critical
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