A 40-year-old female who initially presented with rapidly progressive right-sided weakness headache, urinary incontinence, and global aphasia. MRI brain showed a large T2 hyperintense frontal lesion with hemorrhagic component in addition to smaller left frontal and right midbrain lesions. She rapidly worsened over the next few days with transtentorial herniation requiring decompressive hemicraniectomy. The lesion was biopsied, and pathology evidence of demyelination with perivascular inflammation. Serum MOG antibodies were positive with a low titer of 1:40. She was diagnosed with AHLE and treated with a 5-day course of IV methylprednisolone followed by a 6-week prednisone taper. She had significant clinical and radiologic improvement over the next few months.
Eight months later, she presented with generalized tonic-clonic seizures. MRI showed a new hemorrhagic lesion in the left frontal lobe and another large right frontal periventricular T2 hyperintense lesion. CSF studies showed WBC 47/cumm (96% neutrophilic), protein 49mg/dl, and 19 (>2 unique) oligoclonal bands. Serum MOG antibodies were positive with a low titer of 1:40. She was treated with a 5-day course of IV Methylpednisolone followed by oral prednisone taper. Given the relapsing episodes of AHLE, Rituximab was started to prevent further episodes. She remains relapse-free nine months later. She is clinically stable with persistent expressive aphasia and infrequent breakthrough focal seizures.