Short-term therapy with corticosteroids can lead to progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a disease of the central nervous system caused by JC virus infection. As a general rule PML patients suffer from an acquired or congenital immune deficiency syndrome. Here we present the history of a 78-year-old female patient who was treated with corticosteroids (25–75 mg Prednisolone) for suspected pulmonary sarcoidosis. The patient developed an acute brachio-facial hemiparesis. The cerebral imaging showed focal demyelination but an analysis of the cerebrospinal fluid did not point towards an inflammatory cause of these alterations. Assuming a cerebral manifestiation of the pre-diagnosed sarcoidosis, the dose of the glucocorticosteroids was increased. Soon after admission, the patient's pulmonary capacity deteriorated sharply and she required intubation with artificial ventilator therapy. She subsequently died due to complicating fungal pneumonia. While pathological findings could confirm the diagnosis of pulmonary aspergillosis, the neuropathological workup surprisingly revealed PML as the underlying reason for her neurological symptoms. This unfavourable disease course highlights that even short-term immunosuppression with routine dosages of glucocorticosteroids may lead to PML, despite the lack of indicative clues in the CSF.