This comparative effectiveness trial (CET) in children with suspected focal cerebral arteriopathy (FCA) presenting with arterial ischemic stroke (AIS) or transient ischemic attack (TIA) will compare the use of early corticosteroid treatment (Arm A) versus delayed/no corticosteroid treatment (Arm B). Delayed corticosteroid treatment is given only for those demonstrating disease progression and is initiated as soon as the progression is detected (at any time after randomization). All participants will also receive standard of care therapy (aspirin and supportive care). Sites will randomize participants 1:1 to Arm A or B. Participants will be enrolled and randomized as soon as possible after their stroke/TIA up until 96 hours following the initial stroke/TIA event.
