CHICAGO—Axial spondylarthritis (SpA) is now the preferred name for a set of diseases including ankylosing spondylitis (AS), an inflammatory disease of the sacroiliac joints and spine. The term, reflecting the expanded diagnostic capabilities available today, emerged after the Assessment of Spondyloarthritis International Society (ASAS) established more inclusive classification criteria for inflammatory back pain (IBP) and SpA.
Diagnosis
The term axial spondylarthritis (or axial spondylarthropathy) is a more inclusive term in that it signifies that a reliable early diagnosis can now be made in the absence of X-ray changes. Magnetic resonance imaging (MRI) can detect sacroiliac inflammation before anything becomes evident on X-rays. This is important because the back pain and stiffness associated with SpA often begin in late adolescence to early adulthood, and patients tend to postpone reporting these symptoms to their physicians. One study has shown that one-third of those patients with early onset pain delay consulting a health care professional for more than 12 months after onset of symptoms, assuming that the symptoms will subside.1
In addition, early diagnosis is important because therapies that are more effective if used in the early stages of the disorder have become available. These include tumor necrosis factor (TNF) antagonists.
Another diagnostic tool is genetic testing. There is a genetic predisposition to axial spondylarthritis; studies show that at least one-quarter of patients have an underlying genetic risk for SpA.2 A positive genetic test for HLA-B27, a major disease predisposing gene, supports a clinician’s diagnosis of SpA in the absence of imaging findings.