Abstract
BACKGROUND: Multiple sclerosis (MS) and Takayasu's arteritis (TAK) are two autoimmune diseases that affect the Central nervous system (CNS), but the relationship between them has not been established. CASE PRESENTATION: Here we report the emergence of MS during treatment. Takayasu's arteritis in a 24-year-old Iranian woman with a severe presentation. She was treated aggressively with IV methylprednisolone 1 g/day for 3 days and continued with oral prednisolone, also IV cyclophosphamide monthly. After 2 months, loss of vision led to a diagnosis of Optic neuritis (ON) caused by concomitant MS. CONCLUSION: Differentiating CNS vasculitis associated with Takayasu's arthritis from coexisting MS affecting the CNS is challenging and what is important is to avoid giving a TNF inhibitor.