Progressive Multifocal Leukoencephalopathy in a 62-Year-Old Immunocompetent Woman

Progressive multifocal encephalopathy (PML) is a rare demyelinating disease that typically presents in immunodeficient patients. We report a case of a previously healthy 62-Year-Old woman who suffered from an unsteady gait, throbbing headaches, and progressive left-sided weakness and numbness. Stroke was initially suspected based on imaging and symptoms. A series of follow-up magnetic resonance images of the brain showed a right parietal lesion growing in size as the patient became unable to walk and experienced increasing lethargy and confusion. A biopsy of the lesion was positive for the John Cunningham virus (JCV). A diagnosis of PML was made and she was started on mefloquine. No improvement was seen on this treatment and her condition worsened. Although PML remains uncommon in immunocompetent individuals, it cannot be ruled out based on their immune status. Although the exact cause remains uncertain, underlying or transient states of immunosuppression may be responsible for reactivation of the JCV in these patients. 1. Introduction Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system that typically occurs in immunosuppressed individuals. It is caused by reactivation of the John Cunningham virus (JCV) and infection of glial cells. It is often fatal, with a median life expectancy of less than six months following onset of symptoms [1]. Reports of PML afflicting immunocompetent patients are extremely rare but not unknown. We describe a patient with no previous medical issues and an intact immune system who presented with PML. 2. Case Presentation A 62-year-old female with no past medical history presented to the emergency department after a one-month history of progressive left-sided numbness, weakness, and unsteady gait. She had also experienced multiple falls and bladder incontinence over the past two weeks. She complained of frequent throbbing headaches in the occipital area that were not relieved by analgesics. The patient denied fever, chills, confusion, visual changes, or seizures. She had not sought any medical attention prior to this point and was not on any medication. She was of Portuguese origin and was married with two adult children. She had previously worked as a salesperson. She had never smoked and had no history of illicit drug or alcohol use. She denied recent travel, sick contacts, or exposure to wildlife. Family history was unremarkable. On examination, she was alert and oriented to person, time, and place. Some slight left-sided tongue deviation as well as decreased motor