Non-radiographic axial spondyloarthritis, or nr-axSpA, is a form of arthritis in the family of spondyloarthritis diseases. Nr-axSpA primarily affects the spine, but other parts of the body are also often involved. It causes inflammation in the spine and elsewhere that can lead to various symptoms including pain and stiffness.
Here is a breakdown of the terms associated with non-radiographic axial spondyloarthritis:
- Axial – Relating to or situated in the central part of the body, encompassing the full spine and pelvis.
- Spondyloarthritis – Inflammatory arthritis involving the spine and peripheral joints.
- Non-Radiographic – No definitive damage seen on x-rays of spine, specifically in the sacroiliac (SI) joints.
Non-radiographic axial spondyloarthritis (nr-axSpA) is most closely associated with a highly similar condition, radiographic axial spondyloarthritis (r-axSpA), which is more commonly called ankylosing spondylitis.
Non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) are two sub-types of axial spondyloarthritis. They can be thought of as two ends of the spectrum of axial spondyloarthritis. The difference is that in nr-axSpA, the sacroiliac (SI) joints do not show definitive damage on x-rays, as seen in AS.
Non-radiographic Axial Spondyloarthritis FAQs
Non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) are two forms of axial spondyloarthritis with many overlapping symptoms. The main difference is what an X-ray shows. AS causes definite changes in the sacroiliac joints that can be seen on X-ray, while nr-axSpA does not.
Some people with nr-axSpA go on to develop AS, but many do not. Studies estimate that about 5% to 30% of people with nr-axSpA progress to AS over two to 30 years. Even without this progression, nr-axSpA can cause symptoms as severe as those experienced by people with AS.
A normal X-ray does not rule out nr-axSpA. Diagnosis is based on a combination of symptoms, physical exam, medical and family history, blood tests, and imaging.
Yes. Although nr-axSpA does not cause definitive changes in the sacroiliac joints that can be seen on X-rays, an MRI can detect inflammation in those joints. This can help doctors identify nr-axSpA earlier, before structural changes become visible on X-rays.
Non-radiographic axial spondyloarthritis often feels like ongoing pain and stiffness in the lower back and buttocks. These feelings tend to be worse in the morning or at night and may improve with movement or exercise rather than rest. However, the pain can also affect the neck, hips, shoulders, ribs, knees, or heels, and some people experience fatigue or inflammation in the eyes, skin, or digestive system.
What is Nr-axSpA? Introducing SAA’s newest animated awareness video. Watch as we discuss common signs and symptoms of nr-axSpA, and share helpful information and resources for those impacted.
We thank UCB for their financial support of this educational video. SAA is solely responsible for the content of this video.
Some people with nr-axSpA progress to developing AS, although many do not. Studies have found rates of progression from nr-axSpA to AS ranging from 5% to 30% over 2 to 30 years. In general, male sex, a high level of C-reactive protein in the blood, and a high degree of inflammation as seen on an SI joint MRI are risk factors for progression from nr-axSpA to AS.
The primary feature of nr-axSpA is the involvement of the sacroiliac (SI) joints, which are located at the base of the spine, where the spine joins the pelvis. Nr-axSpA can also cause inflammation, pain, and stiffness in other areas of the body such as the neck, shoulders, hips, ribs, heels, and joints of the arms and legs. Inflammation can also impact the eyes (causing iritis or uveitis), the skin (causing psoriasis), and the gut (causing intestinal pain and other problems).
One key takeaway from recent research is that pain, stiffness, and other symptoms are as severe in people with nr-axSpA as they are in those with ankylosing spondylitis.
Symptoms
The first symptoms of nr-axSpA are often described as persistent pain and stiffness in the lower back and buttocks, which come on gradually over the course of a few weeks or months. At first, discomfort may only be felt on one side, or alternate sides. The pain is usually dull and diffuse, rather than localized. Sometimes, these symptoms can be severe. A person’s sex can affect the location of initial pain in nr-axSpA. For some women, the neck and peripheral joints are often affected first, whereas in men it is more likely to be the lower back.
Diagnosis
A rheumatologist is generally the type of physician who will diagnose and treat nr-axSpA. A rheumatologist has special training in diagnosing and treating disorders that affect the joints, tendons, ligaments, connective tissues, muscles, and bones. Unfortunately, there is no clear diagnostic test for nr-axSpA. This means that a thorough physical exam by a knowledgeable doctor, along with proper blood tests, consideration of family history, and imaging when appropriate are truly key.
While knowledge and awareness of this condition have grown in recent years, unfortunately, many people still go undiagnosed for years, visit numerous physicians with no answers, and are even misdiagnosed with something else before arriving at their nr-axSpA diagnosis. Various factors contribute to an average diagnostic delay of 7-10 years, which translates to delays in accessing effective treatment. This is why visiting a rheumatologist is so important.
Is There a Cure?
There may be no cure yet, but that doesn’t mean there’s no help. Important recent advances have offered more insight into what triggers the condition, and how best to treat it. A holistic approach to nr-axSpA, which treats the whole person, includes exercise, wellness practices, stress management, good nutrition, and medications when you and your doctor determine them to be appropriate.
Who Gets Nr-axSpA?
It is estimated that roughly 1.6 million adults in the U.S. have nr-axSpA (while 3.2 million people have axial spondyloarthritis in general). Nr-axSpA and related conditions often start in young people, usually under the age of 45. They can also sometimes occur early in life, in juveniles (these cases are called juvenile spondyloarthritis).
The male to female ratio in nr-axSpA is close to 1:1. Recent studies have found that women are slightly more likely to have nr-axSpA, with demographic reviews showing that 55%-60% of those with nr-axSpA are women.
The HLA-B27 genetic marker is associated with spondyloarthritis, including nr-axSpA. This association is especially strong in Caucasians: while the marker is found in 7.5% of the general Caucasian population, it is found in up to 70% of Caucasians with nr-axSpA. The gene prevalence varies in other ethnicities.
While testing for the gene can be helpful in making a diagnosis, it is not a diagnostic test. It is simply one possible tool in the search for a diagnosis.
Disease Course/Prognosis
Podcasts
Spondyloarthritis 101
Rheumatologist Abhijeet Danve, MBBS, MD, MHS provides an overview of spondyloarthritis including ankylosing spondylitis, non-radiographic axial spondyloarthritis, and other related diseases.
Gender Differences in Spondyloarthritis
Dr. Bittar provides an overview of spondyloarthritis and gender differences in Spondyloarthritis
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