May is a 25 year-old woman with relapsing-remitting multiple sclerosis (RRMS) who comes to your office for follow-up. She has been doing well on a disease modifying drug (DMD) for the last three years. At the age of 20, May had a bout of optic neuritis and the MRI of the brain and cervical spine showed demyelinating lesions consistent with the diagnosis of MS. With the administration of IV steroids, May recovered to baseline. Two years later May developed subtle weakness of the left arm associated with parasthesias. Her MRI was consistent with an MS flare and she received IV steroids with return to near baseline.