You are a PA working in the neurology ward. A 26-year-old lady is referred from her GP with 3/52 history of progressive clumsiness and left leg stiffness. She works as an ICU nurse and has been unable to go to work for the last 5 days.On examination, there is increased tone in the left knee. Dorsiflexion of the foot causes 5 clonus beats and plantar reflexes are upgoing. Power in left hip and knee are 4/5 with no sensory involvement. Her cranial nerves are intact except upon doing a fundoscopy, you visualise a pale disc. On further questioning, before her admission, she had 3 episodes of blurred vision in her right eye, which lasted for a couple of weeks each and resolved spontaneously. Upon discussing this case with your consultant, what do you think would be the most appropriate initial treatment?