What is non-radiographic axial spondyloarthritis (nr-axSpA)?
Nr-axSpA is a type of inflammatory arthritis of the spine that is undetectable on an X-ray. It is part of the spectrum of a disease called axial spondyloarthritis (axSpA). AxSpA includes two underdiagnosed conditions: nr-axSpA and ankylosing spondylitis (AS). In both conditions, inflammation in the spinal joints can cause chronic back pain, stiffness, fatigue, and reduced mobility. If left untreated, this inflammation can cause irreversible damage.
What are the symptoms of nr-axSpA?
Nr-axSpA leads to symptoms like pain and stiffness in the lower back and spine, as well as possible pain in the neck, hips, and buttocks. Other symptoms include pain at night, stiffness upon waking, fatigue, and loss of mobility.
How is nr-axSpA diagnosed?
Nr-axSpA can be difficult to diagnose because the damage to the spine cannot be seen on an X-ray. Many people live with it for years before they get diagnosed. A rheumatologist will typically look at how inflammation is affecting the entire body, assess the patient’s history, and then run a variety of tests, including physical exams, imaging, and lab tests.
AxSpA disease spectrum
There are two conditions that make up the disease called axSpA. These two conditions are non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS). Both conditions have similar symptoms, including back pain, fatigue, and reduced mobility. The main difference is that spinal fusion or damage from AS will appear on an X-ray, while with nr-axSpA, no definitive damage will appear. Here are the other differences between the two:
Spinal damage will not appear on an X-ray, but may appear on an MRI
Patients are more likely to be female (50-60%)
nr-axSpA may be considered an early form of AS in some patients
Spinal damage will be seen on an X-ray
Patients are more likely to be male
Joint damage and spinal fusion
Can nr-axSpA develop into AS?
Up to 50% of nr-axSpA cases are at risk of progressing to AS, which may cause irreversible spinal fusion.