A 64-year-old male with a long history of back problems was in the swimming pool when he suddenly noticed that his legs had become weak. He struggled out of the pool and called emergency medical services. In the emergency department, he reports that his legs suddenly had no strength, and he was not able to move them. He denies any trauma, loss of consciousness, or visual or speech loss. His only other complaint is an inability to pass urine. On examination, he has significant motor weakness in both legs with numbness all the way from the buttocks to the soles of the feet. He has no sensation in the perineal area and the rectal tone is absent. A Foley catheter is placed and it puts out 800 ml of urine. Which of the following is best for the management of this patient?