Progressive Multifocal Leukoencephalopathy Mimicking a Cerebral Vasculitis Flare.

Area of Science:

• Neuroimmunology
• Infectious Diseases
• Neurology

Background:

• A 68-year-old woman with a history of primary cerebral vasculitis presented with recurrent neurological symptoms.
• The patient was on maintenance azathioprine and had previously received rituximab and cyclophosphamide for her vasculitis.

Observation:

• The patient developed new-onset expressive dysphasia, right upper limb weakness, and right facial weakness.
• Initial CT head showed no acute findings, but subsequent imaging revealed white matter hyperintensities suggestive of PML.
• Cerebrospinal fluid analysis confirmed the presence of JC virus DNA.

Findings:

• The case demonstrates a rare presentation of progressive multifocal leukoencephalopathy (PML) in an immunocompromised patient.
• PML was diagnosed based on characteristic MRI findings and confirmed by JC virus detection in CSF.
• The patient's neurological deficits were attributed to PML, occurring despite immunosuppressive therapy for cerebral vasculitis.

Implications:

• PML should be considered in the differential diagnosis of immunocompromised patients presenting with new stroke-like neurological deficits.
• Early diagnosis and recognition of PML are critical for appropriate management in at-risk populations.
• This case underscores the importance of considering opportunistic infections in patients with autoimmune diseases undergoing immunosuppressive therapy.