Asymptomatic progressive multifocal leukoencephalopathy during natalizumab therapy with treatment

Area of Science:

• Neuroimmunology
• Neurovirology

Background:

• Progressive multifocal leukoencephalopathy (PML) is a rare, often fatal, demyelinating disease caused by the John Cunningham virus (JCV).
• Natalizumab therapy for multiple sclerosis (MS) is associated with an increased risk of PML.
• Early detection and management are crucial for improving outcomes in natalizumab-associated PML.

Observation:

• A 40-year-old patient with a history of aggressive MS, prior mitoxantrone, and 5 years of natalizumab monotherapy presented with asymptomatic PML detected on routine MRI.
• The initial MRI findings suggestive of PML were subtle and atypical.
• The patient was John Cunningham Virus (JCV) positive.

Findings:

• Early diagnosis of PML through vigilant MRI screening enabled timely intervention.
• Proactive management of immune reconstitution inflammatory syndrome (IRIS) with high-dose steroids was initiated.
• Empirical treatment with mirtazapine and mefloquine was administered.

Implications:

• This case underscores the significance of regular MRI surveillance in high-risk MS patients on natalizumab.
• Early detection and a multi-faceted treatment approach, including IRIS management, can lead to a favorable prognosis for PML.
• The findings suggest potential therapeutic roles for mirtazapine and mefloquine in managing PML, warranting further investigation.