Brief Answer: Few months according to the severity Detailed Answer: Myelitis means inflammation of the spine and spine is the part of nervous system that connects nerves from brain to the rest of the body. When myelitis occurs at a particular level the connection of the nerves with the body below that part is broken in a simple language and so they are unable to work properly. There are various causes of the myelitis and many times even the most detailed investigations might come out to be negative and then we call it idiopathic, assuming most of the times that it to be post viral fever. Steroids or methylprednisolone pulse is given to decrease the swelling and reduce the inflammatory response; but the recovery would depend on the causation of the myelitis. Please note that steroids in most of the cases would be continued from 6- 8 weeks post hospitalization in most of the cases. Though regimes would differ from individual to individual. Assuming it has been due to post viral cause, I would predict she would respond well in few months duration. Let's hope your sister responds to the pulse steroid therapy and recovers soon but many myelitis patients might need at least few months to recover from their weakness.... Hope I answered your query. Let me know if you need clarifications. Regards

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