How Non-Radiographic Axial Spondyloarthritis Is Diagnosed: What to Expect at the Doctor

If you are wondering how doctors and patients work together to diagnose non-radiographic axial spondyloarthritis (nr-axSpA), it is likely that you have been on a long journey to suspect you have this type of inflammatory arthritis.

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:

• Non-radiographic axial spondyloarthritis (nr-axSpA)
• Ankylosing spondylitis (AS)

Research shows it can people with symptoms of axSpA a long time to get a diagnosis. In this study, the average day was nearly six years; this study found it can take an average of 14 years.

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 how doctors diagnose it. You can use this resource to discuss your condition with your provider and make sure it is considered as a possible diagnosis option.

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 criteria were 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.

Symptoms of Non-Radiographic Axial Spondyloarthritis

Low back pain and stiffness on either side of where your pelvis meets your spine in your sacroiliac joints is one of the most common symptoms of both non-radiograohic axial spondyloarthritis and ankylosing spondylitis. You may also experience pain and stiffness in your spine and rib cage, which are all considered axial joints (think axis of your body).

In addition to back pain, both nr-axSpA and AS can cause other seemingly unrelated symptoms, including painful red eyes (uveitis); red, flaky skin patches (psoriasis); and chronic diarrhea or gastrointestinal upset and pain (Crohn’s disease or ulcerative colitis). These are all related to inflammation in your body.

You may also have other painful and swollen joints (in addition to your back pain), such as your knees or ankles. This is known as peripheral spondyloarthritis.

Read here about the range of symptoms you can experience with nr-axSpA.

Reasons for Delays in nr-axSpA Diagnosis

Being female

Ankylosing spondylitis was traditionally thought of as a man’s disease, even though more recent research shows it commonly affects women too. This misperception may also impact nr-axSpA diagnoses, even though current research suggests women and men equally develop nr-axSpA.

Research shows it takes women longer to be diagnosed with axSpA of any kind. A study of nearly 3,000 patients across 13 European countries found that men averaged between six to seven years to get a diagnosis, while women averaged eight to nine years. The women had more visits to various specialists, such as physical therapists and osteopaths, before they got diagnosed. This study points to the important role other providers could play in closing this long diagnostic gap.

Lack of Provider Awareness

Non-radiographic axial spondyloarthritis is fairly new in the rheumatology world. It was as recently as 2009 that classification criteria were 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.

“Unfortunately, many primary care providers and other specialists outside of rheumatology don’t consider nr-axSpA when a patient comes to them with low back pain,” Dr. Deodhar says. “I’ve seen so many patients go from one provider to another before they find someone who correctly identifies it.”

Not Suspecting Inflammatory Back Pain

The vast majority of people who seek care for low back pain have mechanical pain, which is caused by degenerative changes in the spine, injury, or strain that will be treated accordingly, Dr. Deodhar explains. This is different from the inflammatory back pain from axSpA. Many providers don’t suspect inflammatory back pain because they are so used to treating mechanical pain.

“People with unidentified nr-axSpA are often referred to an orthopedist or chiropractor who is also used to treating mechanical pain and will try to treat it as such, to no avail,” says Dr. Deodhar, who is leading a study among chiropractors to understand their awareness of nr-axSpA symptoms.

“We are seeing a huge unmet need to educate chiropractors about axSpA and this awareness is also needed for orthopedists, osteopaths and even providers working in spine centers to know how to look for clues to nr-axSpA,” he says.

No ‘Connecting the Dots’ Among Other Specialists

Because someone with nr-axSpA could have gastrointestinal symptoms that lead them to a gastroenterologist, or a painful red eye that leads them to an eye doctor, every specialist treating symptoms associated with axSpA needs to be aware of the signs of this inflammatory arthritis and ask about low back pain and other symptoms so patients can be referred to a rheumatologist if they have the common symptoms. “This doesn’t frequently happen, and this is how nr-axSpA patients are missed, because the whole history is never told,” says Dr. Deodhar.

It’s as if each nr-axSpA symptom is a puzzle piece but no one provider is looking to see how they all fit together.That’s why Dr. Deodhar advocates for improving nr-axSpA awareness among patients so they understand the different symptoms. “Talk to your doctor about ALL of your symptoms,” he encourages.

How Doctors Diagnose Non-Radiographic Axial Spondyloarthritis

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
• Bloodwork
• Imaging, including X-rays and MRIs

Personal and Family History

Your doctor will likely ask the following questions:

How does your back pain affect you?

How you characterize your pain and how your pain affects your life are very important to a rheumatologist, who will begin by asking these specific pain questions:

• Specifically, where do you feel back pain? Do you ever have “alternating buttock pain”?
• What makes your back pain worse and what makes it feel better? Does physical activity improve or worsen your pain?Does rest improve or worsen your pain?
• Have you experienced any trauma to your back or any repetitive injury, perhaps as a result of your occupation?
• Do you experience stiffness in your back? When is it worst and how long does it take to feel better?
• Does your back pain ever wake you from sleep in the middle of the night?

When did your back pain start?

People with nr-axSpA typically start experiencing symptoms before age 40-45. It’s common to first start having symptoms in your thirties, twenties, or even teenage years. If your back pain is first starting in middle age or later, it’s less likely to be inflammatory in nature.

Do you have pain in other parts of your body?

This is an important question to consider because any form of axSpA could affect other parts of your spine and rib cage. You could have arthritis in peripheral joints, like the knees or ankles. It could also present as enthesitis, which is inflammation where the tendons and ligaments attach to bones, such as the Achilles tendon at the heel.

Have you experienced inflammatory conditions in other parts of your body?

Your rheumatologist will want to know about other issues you may be have or have had in the past. Be prepared to answer questions like these: 

• Do one or both eyes ever become red or painful? If so, how long does it take to subside?
• Do you experience any flaky, dry skin patches that persist, even after trying over-the-counter topical lotions?
• How is your digestion? Do you have a sensitive stomach prone to diarrhea that lasts for days? Do you experience intestinal pain, bloody diarrhea, and are you losing weight?

Do any of these symptoms run in the family?

There is a strong genetic component to axSpA, including nr-axSpA and AS, so your rheumatologist will want you to think about any diagnosed or undiagnosed conditions in your family.

It’s valuable to talk to your parents and siblings about any symptoms you are experiencing that may have, too, even if they haven’t been diagnosed with axSpA. Psoriasis and inflammatory bowel disease (Crohn’s and ulcerative colitis) may not have been formally diagnosed but having family members with symptoms of these conditions could be an important clue.

Physical Exam

Your doctor will be looking for signs of inflammation, tenderness, and limited range of motion in your spine and other joints. They may conduct a variety of in-office tests, such as:

• Ask you to bend forward (trying to touch your toes without bending your knees) to assess the flexibility of your lower back. This is called the Schober’s test.
• Have you stand with your back flat against a wall to do a couple of tests that measure the flexibility of different parts of your spine and neck.
• Measure how far your chest can expand when you exhale (axSpa can compromise your ability to do this fully).

Your doctor may physically feel for tenderness (this is called palpation) in certain joints and places around your body, including the SI joints by your pelvis, your Achilles tendon at your heel, and your knees.

Diagnostic Tests

There is no one specific blood or imaging test that can determine with certainty that you do or don’t have nr-axSpA, but several tests can further illuminate a pattern of symptoms indicating the diagnosis.

Blood Tests

Certain blood tests can identify specific markers that people with axSpA commonly have.

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): These blood tests show levels of systemic inflammation in the body. ESR and CRP can be elevated in some, but not all, axSpA patients.
• HLA-B27 genetic marker: People with this variant of the HLA-B gene are at a higher risk for 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. However, some research suggests that people with nr-axSpA are less likely to be positive for HLA-B27 compared to people with AS.
• Other antibody tests: Rheumatoid factor (associated with RA), antinuclear antibodies (associated with lupus), or other tests may be ordered to help rule out other conditions.

Imaging

X-rays and MRIs are the two most common imaging tests used to help diagnose axSpA.

 X-rays: Conventional X-rays of your lower back can identify bone damage in your sacroiliac joint and spine. It would show up as a combination of erosive damage, joint space widening or narrowing, sclerosis, and bony fusions of the sacroiliac joint, Dr. Deodhar explains.

Such damage helps to identify ankylosing spondylitis, but it won’t be seen in patients with nr-axSpA.

MRIs: If no joint damage is seen on X-rays but other factors signal axSpA, your rheumatologist may order an MRI. An MRI sends radio waves through your body to produce images of your body’s soft tissues. It’s much better at seeing the soft tissues inside the bone and around the joints than X-ray, so it can pick up inflammation before actual damage to the bones has occurred.

If you have nr-axSpA, an MRI could show inflammation in the soft tissues around your sacroiliac joint. There could also be swelling, called edema, in the bone marrow of the sacroiliac joints on MRI. However, MRI is significantly more costly than an X-ray, can be more difficult to interpret, and needs to be ordered in the right locations. It’s possible for inflammation to be missed if  read incorrectly.

Because MRIs are more expensive and may be less likely to be covered by insurance, they might be used if an X-ray turns up no damage, but your doctor still strongly suspects nr-axSpA for other reasons.

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,” says Dr. Ruderman. “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.”

Track Your AxSpA Symptoms with ArthritisPower

Join CreakyJoints’ patient-centered research registry and track symptoms like fatigue and pain. Learn more and sign up here.

This educational resource was made possible with support from UCB, a global biopharmaceutical company focused on neurology and immunology.