I for one was diagnosed despite a negative LP. I live in NY and I first went to the top MS specialist at one of the teaching hospitals . He ordered the usual testing and did not make the diagnosis at first,partially due to the negative LP. He ordered a follow up MRI at four months and made a definate dignosis at that time.
He retired about six months later and recomended a doctor at another teaching hospital who upon reading the MRI's confirmed the diagnosis. I have asked about doing another LP a few times over the years but he says it will not tell us anything new.
Policy does not allow us to name doctors but all of the major teaching hospitals in NY run MS centers most of which are very good.
A google search will find you the names of the centers and the doctors who run them and that should give you a starting point if you want to try the NY area.
I had a pain like that earlier in the year and was diagnosed with epidemitis which my urioligest said was, due to not clearing the bladder and urinary tract completely. It can be linked to STD's but not exclusively so do not let a doctor tell you otherwise . (happened to a friend of mine years ago and nearly ended his marrige)
I am not a doctor but what you describe sounds like that including the irregular bowel movements.
I think you should find a urioligest and have it checked out.
It is very rare and there seems to be different types of dyes involved but it does happen. If you enter gadolinium in the search this community at the top of this page you will see a previous disscussion we had on this topic.
It is more than possible to have both. My sister was dignosed after an MRI that was done to check the extent of her disc disease.
I do not know if about the positive lumbar but , it used to be seen as the final test but now a lot of neuro's will not make a diganosis based solely on that. The look for lesions on MRI's as well or a neuro work up that indicates a neurological problem.
I cann't tell you if you have one or the other or both but a second opinion on the MS may not be out of order and if anything can be done to help with your back problem you should check them out as well as the will likely get worse.
The usual MRI protocol includes MRI's of the brain with and without contrast . The contrast is a Dye that shows active inflamation in lesions which can be the cause of a flair. one word of warning is that some people have an allergic reaction to it ,I am always asked if I have seafood allergy so I guess it is related to that in some way.
You say you have evoked potenial testing lined up and you probably should have an lumbar puncture as well.
All this may not lead to a diagnosis of MS but none of them can rule it out completely. My advice would be to find a neuro who specialises in MS or an MS care center for further testing as I would be worried about a neuro who rules out MS after one MRI.
Keep a symptom log and any triggers you notice such as heat cold stress and others.
Let us know how you are doing and any results you get, in the mean time feel free to seekwisdom here or better yet bring some we could all use it.
The simple answer is no a negative spinal does not rule out MS . I know this because I was dignosed despite a negative spinal.
If a neuro told you this he/she is not up on MS.
I have no way of knowing if you have MS or not but as much as I respect your decision to hop of the doctor bandwagon, you may have to go to at least one more for a final diagnosis otherwise if it is MS it may get worse if untreated.
Sorry if that sounds harse but I think it is true,