Parainfectious Acute Disseminated Encephalomyelitis (ADEM) associated with Pneumococcal Pneumonia: A case report

Objective: To describe a case of parainfectious acute disseminated encephalomyelitis (ADEM) associated with pneumococcal pneumonia. Case report: A 48-year-old man presented with cough, dyspnea, and fever. His past medical history was unremarkable. A chest x-ray revealed severe pneumonia with positive urine antigen. Intravenous antibiotic therapy was started, with improvement. Six days later, he complained urinary retention and lower limbs weakness; neurological examination revealed confusion, paraplegia with brisk tendon reflexes and bilateral ankle clonus. Spinal MRI scan showed elongated signal changes from the lower cervical spine to the conus medullaris throughout the whole central area of the spinal cord. Brain MRI scan revealed abnormal signal of the right cerebral peduncle, extending cranially to the internal capsule and caudally to the anterolateral region of the upper brainstem, and a smaller lesion within the left superior cerebellar peduncle. CSF analysis showed increased proteins (116 mg/dL), 26/uL white blood cell count (mainly mononuclear cells), and a concentration of glucose of 51 mg/dL. Blood and CSF culture showed no bacteria and viral screening via Multiplex-PCR tested negative. Oligoclonal bands on serum and CSF were positive with a mirror pattern. Anti-AQ4 antibodies on serum were negative, while anti-MOG antibodies were positive. A nine-day course of intravenous methylprednisolone was administered, followed by oral prednisone. The patient was admitted to a rehabilitation unit for three months and showed a gradual improvement of the mental status and lower limb strength. At one month follow-up visit, he was able to walk without aids, but the bladder function remained impaired with self-catheterization needs. After three months the MRI scan showed a marked reduction of the lesions. Discussion: In the present case, the clinical course, laboratory data and neuroimaging were consistent with parainfectious ADEM [2]. As far as we know, ADEM has never been reported following pneumococcal pneumonia.