Re: Could it be RA?
If tests for RA and lupus have been negative, it is quite possible this could be ankylosing spondylitis with the general joint pains preceding the spinal symptoms. AS usually causes pain and stiffness in the sacroliac joints, felt in low back below waist and into the buttocks. It causes low back pain that progresses upward over time until the joints actually fuse. With high CRP, low complement, plus your symptoms, there is certainly something going on as far as inflammation, and the HLA B27 is specific for AS. It is treatable to reduce the inflammation and slow the progression of the arthritis. Sacroiliac xrays or MRI can be done if you have pain in those joints. I think the rheum clinic would be a good idea. The clinic will have numerous physicians working together, and they often consult with one another on cases that are tricky. I would encourage you to try that, and when you call for an app't, ask to see whatever physician has a special interest in AS if there is one. I think it is your best bet in getting diagnosed and treated.