Breakthrough Disease While on Multiple Sclerosis Immunomodulatory Therapy

A 36-year-old woman with a history of relapsing-remitting multiple sclerosis was evaluated for new multiple sclerosis symptoms accompanied by new, enhancing, white matter lesions on brain magnetic resonance imaging. Her multiple sclerosis presented with L’hermitte sign when she was 24 years old. She had onset of bilateral lower extremity and left upper extremity tingling at age 26 years. Magnetic resonance imaging and cerebrospinal fluid examination at the time were supportive of the diagnosis of multiple sclerosis, and disease-modifying therapy was recommended by her neurologist. She initiated therapy with dimethyl fumarate at age 30 years after several further relapses. Surveillance magnetic resonance imaging showed new gadolinium-enhancing lesions on brain magnetic resonance imaging on each of 3 consecutive yearly scans. Urine culture and sensitivity tests were performed to rule out occult urinary tract infection; results of this testing were negative. magnetic resonance imaging of the brain concurrently showed new enhancing white matter lesions. The patient was diagnosed with clinical and radiographic breakthrough disease activity while receiving therapy for multiple sclerosis. The patient was treated with 5 days of intravenous methylprednisolone for her relapse. After discussion with the patient, it was decided to transition therapy from dimethyl fumarate to ocrelizumab infusions for her breakthrough disease activity. This decision was further supported by the patient’s concerns that she might be entering an early progressive phase of the disease. In patients with spinal-predominant multiple sclerosis, or with symptoms potentially indicating new spinal cord involvement, it may be necessary to include spinal cord imaging to assess for new disease activity.