My wife went through something like this back in 1985. In a few hours time she was a permanent quadriplegic. She showed classic Polio deformities in her limbs that were obvious by the therapist measurements hinting that at some point early in life she possibly also had Polio. Her final diagnoses was Transverse myelitis with several contributing factors such as possible previous Polio as a child in the early 1950's, a weakened physical state due to some stress in her life when it hit, and a narrowing in her spinal cord at C-5/C-6.
It took a year for a diagnoses and she was hospitalized for six months. She got use of her arms and hands back enough to feed herself and write. The Neurologist kept asking about any previous shots such as at that time the flu vaccine which was causing some patients to develop GuillainBarré Syndrome. They ruled it out in about the second week.