What is ankylosing spondylitis? Why is it misdiagnosed?

[#Man stayed up late for a long time with sudden cerebral hemorrhage and half body paralyzed#, suddenly aphasia, only eyes can move] Recently, Shenzhen. Mr. Yang suddenly lost his speech when he was looking at his mobile phone at night. He couldn’t move his right limb and could only open his eyes. After being rushed to the hospital, a CT examination showed that he had a brain hemorrhage of about 20 milliliters. The doctor said that Mr. Yang’s sudden illness was related to his staying up late. After treatment, Mr. Yang’s condition improved significantly.