Makindo Medical Notes.com

• 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-a
• Infliximab Anti-TNF-a
• Etarnecept Anti-TNF-a
• 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

• Progressive multifocal leukoencephalopathy: new concepts