You've probably heard of osteoarthritis, the joint disease that wears down your hips and knees as you get older. But you may be unfamiliar with non-radiographic axial spondyloarthritis (nr-axSpA). It’s a type of arthritis that causes pain and stiffness in your back.
Nr-axSpA is related to a condition called ankylosing spondylitis (AS). Both diseases are a type of spondyloarthritis.
Nr-axSpA can be an early sign of the more serious AS. But not everyone with nr-axSpA gets AS. It’s called non-radiographic because it doesn’t cause enough joint damage to show up on X-rays.
Symptoms
Low back pain is the most common sign of nr-axSpA. It usually starts in your sacroiliac joints, where your spine meets your pelvis. It can differ from common back pain in that your pain:
- Is worse at night and when you sit too much
- May come on slowly and linger for months or longer
Other symptoms of nr-axSpA include:
- Pain and stiffness in your ligaments or tendons, especially the Achilles tendon in your heel
- Swollen fingers or toes (dactylitis)
Causes
Doctors have known that nr-axSpA results when your immune system gets confused and unleashes inflammation on your spine and other harmless places. What they didn’t know was why. Now some researchers believe that a gene called HLA-B27 may be to blame. Specifically, the gene may cause normally “good” bacteria in your body to set off inflammation.
Many people with nr-axSpA have the HLA-B27 gene, as does almost everyone with AS. Still, most people with the gene never get arthritis.
Other risk factors for nr-axSpA include if you:
- Are a young adult 20 to 30 years old
- Have a close family member with either nr-axSpA or AS
- Smoke
Diagnosis
There’s no single test for nr-axSpA, and it won’t show up on X-rays. So it can take years to find the reason for your back pain. Also, the disease mainly strikes when you’re young and healthy, so many doctors may not suspect arthritis right away. Your doctor may use your symptoms and order a blood test to check for the HLA-B27 gene. Also, MRI scans can show inflammation that isn’t visible with X-rays.
Early diagnosis and treatment for nr-axSpA can help ward off complications.
Treatment
As with ankylosing spondylitis, managing nr-axSpA takes a mix of exercise, physical therapy, and medication.
Exercise. It should be a part of your life every day. Exercise relieves pain and the dead-tired feeling you get sometimes. It also helps prevent your spine from getting very stiff.
Drugs. Sometimes, prescription nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin (Indocin) are all the therapy you may need. But they can cause stomach bleeding, heart problems, and other side effects. So take care to use them only when you need to. In other cases, your doctor may try immunotherapy or TNF Inhibitors to target the inflammation.
Physical therapy. You’ll learn how to strengthen your core, the best way to stretch tight muscles, breathe, and get your heart pumping. You can do physical therapy at home. But you may benefit more if you work with a trained therapist.
Complications
Nr-axSpA can cause pain and inflammation in other parts of your body besides your back.
Eyes. A condition called uveitis is one of the most common problems outside your spine. It causes pain, blurry vision, and sensitivity to bright light. Most people with uveitis have the HLA-B27 gene. Uveitis should be treated by an eye doctor.
Gut. You may get ulcerative colitis or Crohn’s disease, both of which are types of inflammatory bowel disease (IBD). It damages your gut wall and may cause severe diarrhea, bloating, and pain.
Skin. About 1 in 10 people with nr-axSpA have psoriasis, a disease that causes red, itchy, and scaly skin.
It’s hard to predict how nr-axSpA will affect you in the long run. Your symptoms may stay the same or worsen. Your condition may turn into AS, or it may not. The chances of that happening are higher for men and for those who have bony growths on their spine.