According to the CDC’s 2012 NHANES study, spondyloarthritis (SpA) –– an inflammatory rheumatic disease –– affects at least 2.7 million adults in the U.S. Though it is fairly common (more common than rheumatoid arthritis), it is largely unknown by the medical community and frequently goes undiagnosed by physicians. The average delay in diagnosis for someone with any form of spondyloarthritis ranges from seven to 10 years.
One big clue that can be helpful in diagnosing SpA is the presence of inflammatory back pain.
“Inflammatory back pain (IBP) is associated with spondyloarthritis.” —Weisman et al. “The prevalence of inflammatory back pain: population-based estimates from the US National Health and Nutrition Examination Survey, 2009–10.” Ann Rheum Dis 2013;72:369-373
Here are three different criteria that can help determine if your patient may have IBP:
IBP if 4 / 5 are present.
IBP if 2 / 4 are present.
IBP if 4 / 5 are present
Other signs of spondyloarthritis can include:
Inflammation of the entheses, where joint capsules, ligaments, or tendons attach to bone. This can be felt in multiple areas of the body from shoulders down to the feet.
Inflammation of an entire digit (a finger or toe.)
Inflammation of the eye. Symptoms often occur in one eye at a time, and they may include redness, pain, sensitivity to light, and skewed vision.
Most cases of spondyloarthritis can be diagnosed or, at least, initially suspected, based on medical history and clinical examination.
Bloodwork may not always be helpful in screening for SpA, as many of the usual inflammatory markers are missing. SpA is seronegative (a negative blood test result), and has no association with rheumatoid factor or antinuclear antibodies. The presence of the HLA-B27 gene marker, however, can be a very helpful clue, though not everyone with SpA will test positive for this marker.
Also, common indicators of systemic inflammation, such as an elevated erythrocyte sedimentation rate (ESR/SED rate) and elevated C-reactive protein (CRP) are not always present in SpA patients.
One of the hallmarks of spondyloarthritis, particularly of ankylosing spondylitis, is involvement of the sacroiliac (SI) joints. Inflammation of the SI joints, called sacroiliitis, can be seen on MRI. Using conventional X-rays to detect this involvement can be problematic because it can take from seven to 10 years of disease progression for changes in the SI joints to be serious enough to show up on X-ray.
Note that spondyloarthritis can present differently at onset in some people. This tends to be the case in women more than men. Quoting rheumatologist Dr. Elaine Adams, "Women often present in a little more atypical fashion so it's even harder to make the diagnosis in women." For example, many women have anecdotally reported that their symptoms started in the neck rather than in the lower back.
If you suspect your patient may have spondyloarthritis, please refer them to a rheumatologist as soon as possible. Early diagnosis and commencement of appropriate treatment can mean much better outcomes.
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