It’s not easy to get diagnosed with a condition that most people — including some doctors — are not familiar with. Such is the case with non-radiographic axial spondyloarthritis (nr-axSpA), a form of inflammatory back pain that is part of a spectrum of disease known as axial spondyloarthritis (axSpa).
Non-radiographic axial spondyloarthritis falls under the umbrella term of axial spondyloarthritis, which includes types of inflammatory arthritis that primarily affect the spine and the sacroiliac (SI) joints that connect the lower spine to the pelvis, resulting in pain in the lower back, hips, and buttocks. There are two subtypes of axSpA:
Inflammatory back pain means the pain is due to an overactive immune system causing inflammation in the joints in the spine and pelvis. This is different from mechanical back pain, which means the pain is due to a disruption in the way the components of the back (the spine, muscle, intervertebral discs, and nerves) fit together and move, according to the National Institute of Neurological Disorders and Stroke.
Mechanical back pain can be due to muscle strains or slipped discs, whereas inflammatory back pain can be more like having an autoimmune condition.
But many people with symptoms of non-radiographic axial spondyloarthritis have no idea what it is, or what the difference is between inflammatory and mechanical back pain. They just know their lower back hurts, their hips or buttocks may hurt, and they may have other seemingly unrelated symptoms too, such as psoriasis or diarrhea.
It can take years — or even decades — to get diagnosed with axSpA from the time you first start experiencing symptoms. Getting diagnosed can take even longer for women because these diseases were traditionally thought to strike men more frequently. This delayed diagnosis, debilitating pain, and subsequent loss of function can mean people miss out on enjoying even the simplest activities.
The path to getting diagnosed with any kind of axSpA can be challenging for many reasons, but non-radiographic axial spondyloarthritis is particularly difficult because it is a “newer” diagnosis that many patients and some doctors may not be aware of.
The kind of doctor who can best diagnose and treat/manage non-radiographic axial spondyloarthritis is usually a rheumatologist, which is a doctor who treats musculoskeletal disease and systemic autoimmune conditions that affect the joints, muscles, and bones.
However, not even all rheumatologists have the same knowledge of the condition, according to this recent study of 125 nr-axSpA patients, of whom half had to see two rheumatologists before getting their nr-axSpA diagnosis.
This article will help you understand what non-radiographic axial spondyloarthritis is and what the main signs and symptoms are. You can use this resource to discuss your condition with your provider and make sure it is considered as a possible diagnosis option.
What Is Non-Radiographic Axial Spondyloarthritis?
The name is a mouthful but makes sense once you break it down:
- “Non-radiographic” means that inflammation from the disease hasn’t caused bone damage to your sacroiliac joint (where your spine meets your pelvis) that is visible on X-rays, as compared to a more advanced form of the disease.
- “Axial” refers to where in the body symptoms primarily occur: in the spine, chest, and sacroiliac joints located in the center of the body.
- “Spondyloarthritis” is an umbrella term for a family of inflammatory arthritis conditions that occur when your immune system mistakenly attacks your spine and other joints, as well as connective tissues like ligaments or tendons (called enthesitis). In addition to the axial forms of the disease, peripheral spondyloarthritis can impact other parts of your body, including extremity joints like the knees and ankles, as well as your gut, eyes, and skin.
Non-Radiographic Axial Spondyloarthritis vs. Ankylosing Spondylitis
Non-radiographic axial spondyloarthritis means that the inflammatory back pain has not caused joint damage that is visible on X-rays. If the disease progresses to the point that bone damage around your sacroiliac joint can be seen on X-ray, then the condition is called radiographic axSpA or ankylosing spondylitis (AS). “Ankylosing” means when a joint becomes stiff. In advanced cases of untreated AS, the vertebra can get damaged enough that they fuse together, causing a stiff spine that loses some flexibility.
“The terms ‘nr-axSpA’ and ‘AS’ are used to describe different points in the spectrum of disease that is spondyloarthritis,” says rheumatologist Eric Ruderman, MD, a Professor of Medicine at Northwestern Medicine in Chicago. “We use this distinction to classify the extent of damage the disease has caused, but the symptoms may be quite similar.”
In other words, someone with nr-axSpA and someone with AS can have similar symptoms and disability. AS may show more damage on imaging, but that doesn’t necessarily mean someone with nr-axSpA has less debilitating symptoms.
Some patients with nr-axSpA will ultimately develop AS while some never progress to AS, according to according to rheumatologist Atul Deodhar, MD, MRCP, Professor of Medicine and Director of Rheumatology Clinics at Oregon Health & Science University in Portland, Oregon.
Understanding this spectrum of disease (and what causes nr-axSpA disease progression) is an active and ongoing area of research.
The disease itself is fairly new in the rheumatology world. It was as recently as 2009 that classification criteriawere presented to help distinguish between nr-axSpA and AS for the sake of conducting clinical trials of medications to treat these diseases. It is taking time for doctors (including rheumatologists, primary care doctors, orthopedists, and other providers who treat back pain) to learn about non-radiographic axial spondyloarthritis and its symptoms.
There’s no single test or red-flag symptom that can clinch a diagnosis of nr-axSpA. Rather, doctors look for clusters of symptoms that are common in axial spondyloarthritis. It’s important to be very detailed about the nature of your back pain (such as: Is it worse with rest or activity? Does it ever wake you in the middle of the night in pain?) and other symptoms (such as gastrointestinal pain or eye inflammation) because, as you’ll see below, they are more related than you think.
“Every symptom you are experiencing is important to share when you are talking to any doctor about your back pain because it can all be related,” Dr. Ruderman stresses.
Signs Your Back Pain Could Be Non-Radiographic Axial Spondyloarthritis
There are several common symptoms that can signal to a rheumatologist that you could have nr-axSpA, although you don’t need all of these symptoms to have it. Keep in mind that these symptoms also occur in ankylosing spondylitis. There’s no way to tell the difference between nr-axSpa and AS based on symptoms alone — you’ll need imaging, including X-rays and MRIs.
1. Inflammatory (not mechanical) back pain
Pain that strikes in your lower back on either side of your spine at the top of your pelvis and potentially radiates into either buttock is likely the first symptom of axSpA that a rheumatologist will ask you about.
Low back pain is a common complaint for many reasons — including muscle strain or slipped discs — that are not inflammatory but considered mechanical pain. Several characteristics make inflammatory back pain unique:
- The back pain is worse with rest and gets better with activity and movement. This can cause back pain in the middle of the night, when you first wake up in the morning, or when you sit for a long period of time. Inactivity triggers inflammatory chemicals to build up, causing stiffness in the joint and ligaments around your sacroiliac joints.
- The back pain may improve with anti-inflammatory medication, such as naproxen (Aleve) or ibuprofen (Advil).
- The back pain tends to come on slowly, rather than an acute twinge. It can come and go but lasts steadily for at least three months.
- The back pain may feel better with exercise and stretching.
- The back pain strikes at a young age, commonly in the 20s or 30s, or even the teenage years. Back pain that starts after age 45 is more likely to be from another cause.
Because the condition is non-radiographic, it may require a closer look using magnetic resonance imaging (MRI) to see lower back inflammation in your soft tissues. However, MRI cannot always capture this inflammation. Likewise, sometimes there can be inflammation on an MRI but it’s not because of spondyloarthritis.
2. Stiffness in your lower back
Stiffness accompanies the pain in your lower back when you have nr-axSpA because inflammation in the sacroiliac joints restricts your movement. In addition to lower back pain, are you also tight in your lower back and feel restricted in your movement and flexibility? If so, this is important to tell your doctor when you characterize your pain.
“Stiffness can be a difficult symptom to describe because people may perceive the feeling differently than a doctor would characterize it. To understand if a patient has stiffness in their lower back, I ask them to tell me how long it takes from when you wake up until you feel as good as you feel all day,” Dr. Ruderman explains.
When a patient says it takes an hour or more for their back stiffness to improve in the morning, this is a red flag for nr-axSpA, Dr. Ruderman says.
3. Under age 45
Younger people presenting with nr-axSpA symptoms have a stronger likelihood of having this condition. People over age 45 can have nr-axSpA, but as you get older, low back pain is more likely the result of long-term wear and tear or a degenerative spine disease that becomes more common with age.
It’s not common for people in their 40s to experience symptoms of inflammatory back pain for the first time, although many people may be diagnosed at this age because of years of delays and misdiagnoses.
4. Chronic diarrhea and digestive issues
The same inflammation from an over-active immune system that is causing back pain can also affect the gastrointestinal tract. The “spondyloarthritis” umbrella of diseases also includes enteropathic arthritis, which occurs in inflammatory bowel disease like Crohn’s and ulcerative colitis. Some people with spondyloarthritis develop these associated intestinal conditions.
You could have chronic diarrhea that lasts more than two weeks, possibly with blood in the stool, abdominal pain and bloating, and weight loss.
5. Psoriasis skin plaques
Psoriasis is another inflammatory disease that is more common in people with spondyloarthritis. Psoriasis can overlap with low back pain when you have nr-axSpA. These skin lesions are the result of your immune system causing your skin cell turnover to go into overdrive, leaving dead skin cells on the surface to develop lesions, according to Mayo Clinic.
You could have red or purple scaly skin patches that itch and are difficult to heal. These patches of inflamed skin can develop on your lower back, elbows, knees, legs, soles of the feet, scalp, face, palms, and elsewhere.
6. Red, swollen eyes (uveitis)
Your eye health can be a clue of nr-axSpA. If the whites of your eyes are very red and swollen, this might be a condition called uveitis, or inflammation of the middle layer of tissue in the eye wall (uvea). Uveitis tends to come on suddenly and take days to resolve and can come and go. While uveitis can be caused by injury or infection, it can also be triggered by an overactive immune system, according to Mayo Clinic, as is the case when you have nr-axSpA.
7. Tendon and ligament inflammation (enthesitis)
Do you ever experience pain and swelling above your heel (Achilles tendon), under your heel (plantar fascia), or at your elbow (tennis elbow)? In addition to lower back, this pain where tendons and ligaments attach to bone is a common symptom in nr-axSpA. Enthesitis is unique to spondyloarthritis and can be an important way that a rheumatologist distinguishes your nr-axSpA from a different type of rheumatic disease, such as rheumatoid arthritis.
Getting Diagnosed with Non-Radiographic Axial Spondyloarthritis
In addition to asking about these physical symptoms of nr-axSpA, a rheumatologist will ask about your family history of any related conditions, such as if your parents or siblings ever experienced inflammatory bowel issues or psoriasis.
Thinking about family history can be a lightbulb moment for patients, Dr. Ruderman says. “Often when I ask a patient about family history of key symptoms, they will say, ‘oh yes, my mother has Crohn’s.’ Until this conversation they may wonder why diarrhea would be related to back pain — that’s a very important part of our discussion when I take their history.”
This is because nr-axSpA and related inflammatory conditions can be genetic. For example, HLA-B27 is a genetic variation of the HLA-B gene that is associated with axSpA. HLA-B helps your immune system distinguish between your own cell proteins and those from a virus or bacteria that your body should fight.
While you can have nr-axSpA and not have HLA-B27, a positive test will signal to your rheumatologist that you have a stronger chance of having nr-axSpA, according to rheumatologist Atul Deodhar, MD, in an article for the American Journal of Managed Care.
There’s no single test that can clinch a diagnosis of non-radiographic axial spondyloarthritis. Doctors diagnose nr-axSpA after considering all of the following:
- Personal and family history
- Physical exam
- Imaging, including X-rays and MRIs
Read more here about the tests and questions a rheumatologist will use to diagnose nr-axSpA.
The Importance of Early nr-axSpA Diagnosis and Treatment
The sooner nr-axSpA can be accurately diagnosed, the faster a person can get start treatment, get their inflammatory pain under control, and reign in other debilitating symptoms of axSpA.
Some patients with nr-axSpA will ultimately develop AS while some never progress to AS. With AS, there can be permanent damage to your spine, including fusion of your vertebra.
Even if there is no progression to AS, the pain alone that a person experiences from nr-axSpA can be debilitating and negatively impact a person’s quality of life, ability to work, and personal relationships. It can lead to overlapping pain conditions such as fibromyalgia, which is characterized by widespread pain, as well as anxiety and depression. Because axSpA is driven by underlying inflammation, it can also be associated with other comorbidities, such as an increased risk of heart disease.
What’s more, there are good treatments for axSpA that can control symptoms, improve quality of life, and may help prevent disease progression. But these medications are very different from treatments recommended for mechanical back pain, which is why figuring out the root cause is so important.
“It’s a very treatable disease — once diagnosed correctly,” Dr. Ruderman says. “I see young patients who finally get to me after seeing other providers looking for the cause of their worsening back pain. They’ve stopped exercising and playing sports because of the pain, yet within a few months of getting diagnosed and treated for nr-axSpA, they are active again and feeling better than ever.”
That’s why it’s so important for people to understand the symptoms of nr-axSpA and who can help them treat it, Dr. Ruderman stresses. “Once a person understands that their back pain is inflammatory and can articulate it to their doctor, they can be referred to a rheumatologist and get the treatment that can make them feel better than they may have realized they could.”
Finding the Right Treatment
The first-line medications for axSpA are non-steroidal anti-inflammatory medications, which help relieve inflammation and pain. If those aren’t effectively managing symptoms, your rheumatologist will likely recommend biologic medications, which act on more targeted parts of the immune system to stop inflammation. These medications include tumor necrosis factor inhibitor (TNF) biologics and interleukin-17 (IL-17) inhibitor biologics.
As of now, there are three medications that are FDA-approved specifically for nr-axSpA, though other kinds are approved for the radiographic form, ankylosing spondylitis:
- Certolizumab pegol (Cimzia)
- Ixekizumab (Taltz)
- Secukinumab (Cosentyx)
“Once you get a diagnosis and start treatment, it’s important to maintain regular and open dialogue with your rheumatologist about how your treatment is making you feel,” Dr. Ruderman stresses. “Continuing to track your symptoms is an important way patients and doctors work together to find the most effective therapy to get you moving and keep you moving.”
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This educational resource was made possible with support from UCB, a global biopharmaceutical company focused on neurology and immunology.
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