post viral syndrome question. (although I have MS)

Prior to my MS diagnosis in 1998,..all the drs kept saying I had a post viral syndrome. Does that have any bearing at all now that we know I have MS?....It was very confusing to me at the time. My symptoms at the time were diarrhea for 8 days straight , followed by diplopia (double vision) 6 days later,..followed by paresthesia that started in the feet after an "unexplained" fall which progressed within days to the T-3 level (chest).  The drs were stumped as they kept insisting post viral syndrome. I was finally diagnosed with MS about 8 months later. My question is this,...What was all the talk of a post viral syndrome when it would up being MS? Now that we know it is MS, does post viral syndrome have anything to do with this or they just didn't know? Even with the small white matter lesions on the MRI they were saying they believed post viral syndrome rather than MS....Lastly,..Can my diagnosis with certainty now rule out post viral syndrome? These are things I have always wanted to understand.

I would really like a doctor to tell me detailed thoughts. Thank You.