Vikas Majithia, MD, on Nonradiographic Axial Spondyloarthritis

Dr Majithia clarifies differences and similarities between radiographic and nonradiographic axial spondyloarthritis, including diagnosis, treatment, and progression.

Vikas Majithia, MD, is a senior associate consultant and division chair of rheumatology at Mayo Clinic-Florida in Jacksonville.

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Transcript:

Dr Vikas Majithia:
Hi, I'm Vikas Majithia, Senior Associate Consultant at Mayo Clinic-Florida, currently the division chair. I'm excited to talk about axial spondyloarthritis.

This is a heartened topic and frequently confusing, regarding the clinical presentation. By and large, these patients who have axial spondyloarthritis present with two kinds of clinical presentations. Some of these patients who have inflammatory back pain and are diagnosed with axial spondyloarthritis will have radiographic findings. That means you can see changes on plain radiographs. Some of these patients who do have radiographic changes will have Modified New York Criteria positive. But a number of these patients do not have radiographic findings, which can be seen on plain radiographs of their spine or sacroiliac joints. These are the patients who have non-radiographic axial spondyloarthritis, and that's where the confusion comes. So who are these patients who have non-radiographic axial spondyloarthritis and how to diagnose them? So these patients tend to have clinical features.

A number of them have HLA-B27 positivity, but not all, and they tend not to have findings on the radiographs, but some of them have findings on MRI, which would involve inflammatory changes on MRI of the spine, as well as the sacroiliac joints. But I also want to caution the audience that these patients can be diagnosed with the clinical features alone. If they meet some of the clinical features in the ASAS classification criteria, they have non-radiographic axial spondyloarthritis. A number of these patients of course, have inflammatory back pain, but they also can have history of psoriasis, inflammatory bowel disease or uveitis. Some of these patients have dactylitis and enthesitis. So these are the clinical features you are looking for. Some of these patients have a very strong family history. What is the other thing, which is confusing, whether there is a continuum between patients who have non-radiographic axial SpA and radiographic axial SpA.

This has been looked at in a number of ways. So I would like for everybody to think about a flowing stream, which has blockages as well as it can change into and runs into the ocean at the end, or can form a lake. So it can be various stages at various times. Some of the patients will have just inflammatory back pain and they will never be diagnosed with any of the axial SpAs. The ones who get diagnosed at the early stage, they will usually be diagnosed with non-radiographic axial SpA. Some of these patients will progress to having radiographic stage. Some of them will remit spontaneously and some of them will continue to stay at non-radiographic axial SpA. So about 6% of patients in United States have inflammatory back pain, but a very small percentage of them will lead to having actual diagnosis of these disorders.

When we look at a recent study presented at [inaudible 00:03:28], about 16% of these patients who had non-radiographic axial SpA progressed to having radiographic axial SpA. The rest of them either remained in the same stage or remitted or had a different outcome. So it's important to know that not everybody who has non-radiographic axial SpA will lead on to having radiographic axial SpA. There are risk factors, male sex being one of them, HLA-B27 positivity being another one of them, which can increase the risk of them developing the radiographic stage. The second thing, which is almost always confusing, is this a milder form of disease, since they don't have radiographic changes? The answer is no. When you look at the disease burden as well as the clinical symptoms, they are about the same. Then one more question which is asked is what about the sex differences?

That's where it gets tricky, and it is true. Women tend to have more non-radiographic axial SpA and men tend to have more radiographic axial SpA. Similarly, there are sex differences in the way they present, some of the clinical features and some of the cause. In a recent study, it has also been found that they may also be responding differently amongst different sexes to the therapy. So all that has to be considered in these patients, but by and large, they are not any milder than patients who have radiographic disease. Hence, the last question, which is confusing and should be answered is how do we manage them? We manage them the same way. Both of these patients, if they have appropriate reason to go on a biologic, if they have failed NSAIDs and they have significant clinical symptoms and disease burden, they should be managed in the same way, whether they have radiographic disease or non-radiographic disease. I hope that clarifies some of the confusing points between the presentations of axial spondyloarthritis. Thank you.