What caused an interruption to, and almost the end of, FDR's political career in 1921?

Franklin D. Roosevelt's political career almost came to a quick end in 1921 due to his polio diagnosis. At the young age of 39, FDR was diagnosed with polio after experiencing several different concerning health symptoms. This included numbness, a constant high fever, and the inability to feel his face. Ultimately, this diagnosis left FDR in a wheelchair from 1921 onward. Even though he was in a wheelchair, the public never really saw him in this state as he arranged photo opportunities and speeches so that he was propped up or sitting down in a standard chair.