Learning objectives
- Relevant as a stroke mimic
- Understand what is PML
- Recognition of PML
- Treatment of PML
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Introduction
- JC Virus Encephalopathy seen in immunocompromised
- AIDS-related condition of the brain
- Oligodendrocytes are the preferred CNS cells infected by JCV
- JC is a ubiquitous human papovavirus
Aetiology
- The cause is felt to be JC virus which is a common infection
- 40-90% of the general population have been exposed to JC virus
- Usually asymptomatic and trivial unless immunocompromised
- Infection of oligodendrocytes and demyelination
- Advanced cancer or bone marrow transplants
- HIV with very low CD4+ cell counts
Drug Causes
- Tysabri (natalizumab) Anti- a4 integrin
- Gilenya (fingolimod)
- Tecfidera (dimethyl fumarate)
- Rituximab Anti-CD20 Efalizumab Anti-CD11a
- Adalimumab Anti-TNF-α
- Infliximab Anti-TNF-α
- Etarnecept Anti-TNF-α
- Ruxolitinib Inhibitor of Janus kinases (JAKs) 1 and 2
Clinical
- Focal neurology depending on site and size of white matter lesions
- Weakness, sensory loss, ataxia, brainstem signs
- Altered cognition, visual loss
Differentials
- Multiple sclerosis
- Susac syndrome
- Progressive multifocal leukoencephalopathy
Differentials in the AIDS patient
- Toxoplasmosis
- CNS lymphoma
- AIDS dementia complex
- Cryptococcal meningitis
- HIV encephalopathy
- Cytomegalovirus (CMV) infection
- Herpes infections
Investigations
- FBC, U&E, CRP may be elevated
- HIV test, syphilis
- MRI brain shows single or multiple T2 weight lesions in the white matter. Can involve the corpus callosum similar to Glioma or lymphoma
- LP with PCR for Herpes viruses, JC virus etc. Cell count.
- Brain biopsy
Management
- Diagnosis depends on clinical symptoms with MRI and CSF changes and Serology.
- If HIV and low CD4 start HAART but 10-20% experience immune reconstitution inflammatory syndrome (IRIS) which can cause brain swelling and herniation
- Cytosine arabinoside (ara-C, cytarabine, Cytosar-Ur), is given through a shunt directly into the brain
- Studies of the anti-CMV drug, cidofovir, first looked encouraging for treating PML.
- Some with CD4 > 200 recover without treatment other than anti-HIV therapy
- May be a role for steroids
Reference
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