Axial Spondylarthritis without Radiographic Evidence: Causes and Remedial Measures
Non-Radiographic Axial Spondyloarthritis (nr-AxSpA) and Ankylosing Spondylitis (AS) are two related conditions that fall under the umbrella of spondyloarthritis. Although they share similarities, there are significant differences between the two, particularly in their diagnostic imaging findings, disease progression, and treatment approaches.
Diagnosis
Nr-AxSpA is characterised by clinical symptoms such as inflammatory back pain and sacroiliac joint involvement, but without definitive radiographic changes on X-rays. These changes may be detected by MRI or other imaging modalities that identify inflammation before structural damage appears. On the other hand, AS involves more advanced disease, where radiographic sacroiliitis (changes visible on X-rays) is present, showing structural damage to the sacroiliac joints and spine.
Disease Progression
Nr-AxSpA may represent an earlier stage in the spondyloarthritis spectrum. Some patients with nr-AxSpA eventually progress to AS with radiographic changes over time, while others may remain stable without progressing. AS is considered a more advanced form with chronic inflammation often leading to spinal fusion and ankylosis (bone fusion), which is not typically seen in nr-AxSpA.
Treatment
Both nr-AxSpA and AS share similar treatment strategies targeting inflammation and symptom relief. First-line treatment generally involves Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) to control pain and stiffness. If these treatments are not effective, biologic disease-modifying antirheumatic drugs (bDMARDs) such as TNF inhibitors and IL-17 inhibitors, and targeted synthetic DMARDs (e.g., JAK inhibitors), are used in both conditions.
Medications like infliximab have demonstrated medical necessity for treating nr-AxSpA specifically, reflecting the overlap in pharmacologic management. Management strategies also include multidisciplinary care, monitoring for extra-musculoskeletal manifestations (e.g., uveitis, Inflammatory Bowel Disease, psoriasis), and non-pharmacological approaches.
Distinguishing Features
Nr-AxSpA differs from AS mainly in the absence of radiographic damage despite similar symptoms and inflammatory processes. While treatment approaches overlap substantially, nr-AxSpA patients might be diagnosed earlier in the disease course before irreversible joint changes appear.
Doctors consider both nr-AxSpA and AS to be forms of spondyloarthritis that exist at opposite ends of the same disease spectrum. Doctors typically use MRI scans to confirm a diagnosis of nr-AxSpA, as this imaging technique can indicate an active inflammation of the SI joint.
Uveitis, a type of inflammatory eye condition, may cause eye pain and blurred vision, and around 15% of people with nr-AxSpA develop uveitis. If nr-AxSpA worsens to the extent that joint damage is visible on spinal X-rays, doctors will change the diagnosis to Ankylosing Spondylitis (AS), a more severe form of spondyloarthritis. Around 10 to 40% of people with nr-AxSpA will develop AS over the course of 2-10 years.
In summary, nr-AxSpA and AS are related conditions, but their primary difference lies in the absence of radiographic damage in nr-AxSpA despite similar symptoms and inflammatory processes. While treatment approaches overlap, nr-AxSpA patients might be diagnosed earlier in the disease course before irreversible joint changes appear.
Spondyloarthritis, specifically Non-Radiographic Axial Spondyloarthritis (nr-AxSpA) and Ankylosing Spondylitis (AS), are chronic diseases under the umbrella of medical-conditions known as spondyloarthritis. In the diagnostic process, while nr-AxSpA presents with inflammatory symptoms and sacroiliac joint involvement but lacks definitive radiographic changes on X-rays, AS involves structural damage to the sacroiliac joints and spine, as visible on X-rays. Health-and-wellness professionals may utilize scientific advancements, such as MRI scans, to confirm a diagnosis of nr-AxSpA and identify active inflammation.
