Migraine, Head, Legs Effected, Vomit. Blood In Urine. What Could Be Causing These?

Hi. I am trying to find out what could possibly be wrong with my wife. She has been in hospital since 12 February unable to walk or even stand up. This problem came on following a migraine which affected the right side of her head. She also vomited heavily as a result of the migraine. From the next day she had no power or movement in her legs. She is able to move her feet slightly but the legs themselves do not move. Her upper body is functioning as normal and she no longer has a headache. Doctors have done lots of tests including MRI scans of head and back, a myriad of blood tests and an ultrasound of her stomach area. All of these have shown nothing that would be causing these symptoms. The doctors think, therefore, that this could have been caused by a virus but cannot pinpoint which virus or how it should be treated. They are running out of ideas so what I would like to know is has anyone else had this kind of problem and what caused it, and what other tests should we consider getting done? It is now basically three weeks. It may be unconnected but she may also have a bladder infection as today she has passed some blood in her urine. Any help or ideas appreciated.