The people who are on prolonged steroids, there are always few thing, which need to be considered;
1) The occult infection. These infections are of rare variety and are not detectable by the common cultures. The virus and fungal infection or rare type needs to be considered. The condition is considered as immunocompromised host and opportunistic infection needs to be looked by the infectious disease specialist. A persistent look out in urine, blood, stool, sputum by different cultures would help identify the organisms. Atypical mycobacterium is also a possibility.
2) The second consideration would be looking for the secondary systemic complication of the Crohn's disease. Despite going in remission and main disease being quiescent, the systemic complications can progress and since it is an autoimmune process, can involve other systems.
3) A third possibility to be considered is neuropathy. Deficiency of vitamins B1, B6, B12 can cause all these symptoms. To start with, a serum vitamin B12 levels should be ascertained. A normal level of this should be followed for the other deficiency disorders to looked for. Prolonged steroids and long history of Crohn's disease, both predisposes for the deficiency disorders. Steroid myopathy, and autonomic neuropathy and toxic neuropathy would be other things to be considered by the neurologist.
Hope this helps.
Please feel free for your follow up questions.