It's interesting that you say it takes 10 years for damage to show up. The rheumatologist I saw before basically told me that if the scan was clear there was no arthritis or Inflammatory process happening and it was fibromyalgia. So, going off everything I have been told in the last few days, it sounds like he should of at least monitored things to see how they progressed?
So, it is true that it can take up to 8-10 years for x-ray damage to show up for SpA. When there is damage visible on x-ray, it is called AS. AS is different from axial SpA or peripheral SpA or enteropathic arthritis. They are all in the same family, but they are all a little bit different.
Inflammation should be visible on an MRI if it is Spondyloarthritis -- inflammation shows up immediately and does not take time to show the way damage does. If it's a peripheral joint, like a knee, then even an ultrasound should be able to show inflammation (though obviously an MRI is more accurate).
I think I remember you having a nuclear bone scan? Those are not used anymore for diagnosing SpA. They are not very accurate. An x-ray or an MRI is really the gold standard, with of course, a clinical examination.
The rheumatologist is usually able to tell from examining the joint whether there is inflammation. An inflamed joint is often red, warm or swollen. However, in SpA, joints don't just get inflamed, tendons do too. Enthesitis is inflammation where tendons and ligaments insert into the bone. Sometimes you can see swelling, other times, not so much. Right above the knee is a common enthesitis site. The heels are also common enthesitis sites.
The blood test for AS is usually HLA B27 - a gene. If you have it, you are more likely to have SpA or AS. But even if you are negative for it, you can still have some sort of SpA (just much less likely that it is AS).
You also may have elevated ESR and CRP, but 40% of people with SpA don't, so you might not.
For an AS diagnosis, you need damage to the SI joints on x-rays. For SpA, you just need evidence of inflammation - enthesitis or arthritis or both.
Here are the criteria for SpA:
New ASAS Classification Criteria
There are two sets, or arms, of the ASAS criteria: the imaging arm and the clinical arm.5 Each set is applied to patients with chronic (more than three months) back pain, the onset of which occurs at less than 45 years of age.
The imaging arm requires only one clinical parameter plus sacroiliitis (X-rays or MRI):
The sacroiliitis should show definite radiographic disease at grade 2 bilateral or grade 3 to 4 unilateral (according to modified NY criteria 1984); or
There should be active (acute) inflammation of sacroiliac joints on MRI, highly suggestive of sacroilliitis associated with SpA.
The clinical arm requires a positive HLA-B27 test plus two other clinical parameters, such as:
IBP;
Arthritis;
Enthesitis;
Uveitis;
Psoriasis;
Crohn’s disease/ulcerative colitis;
Good response to NSAIDs;
Family history of SpA;
Elevated C-reactive protein; and
Presence of HLA-B27.
It does place emphasis on SI joints but you can have what's called "peripheral SpA" without having SI joint involvement.
It's all a bit confusing, but a rheumatologist should be able to tell by examining you and hopefully doing an MRI or ultrasound whether your joints are actually inflamed or whether they just hurt.
If they are just painful, that's called arthralgia and that is part of Crohn's. It does not need to be treated independently of the Crohn's - it should get better when the Crohn's gets better.
Your IBD team should be able to order an MRI but really you should be seeing a rheumatologist. I know that is difficult though, so maybe they should just focus on treating it for now. I would ask to be referred to a rheumatologist at some point - if you do have inflammatory arthritis, you need to be monitored. There is the possibility of joint damage and you need to make sure you are being treated aggressively enough -- and only a rheumatologist can determine the state of your joints.
