Most of us are aware of the radiographic changes associated with ankylosing spondylitis; however, in the past decade AS has come to be considered a subset of a broader more prevalent diagnostic entity referred to as axial spondyloarthritis (axial SpA). The prevalence of axial spondyloarthritis in the U.S. is approximately 1.2 percent of the adult population – about the same percentage of people diagnosed with rheumatoid arthritis.1
Newer classification criteria recognize that ankylosing spondylitis does not necessarily include radiographic changes, but is considered part of the continuum of the same disease as classic AS.1-2 Patients who have had back pain for three or more consecutive months and are under the age of 45; who have had the presence of sacroiliitis confirmed on MRI or plain radiography; and who have at least one clinical or laboratory finding characteristic of spondyloarthritis should be diagnosed as having AS.
The inclusion of MRI as a criterion has been extremely helpful in the diagnosis of AS that does not present with classic radiographic findings. With the option of treatment with tumor necrosis factor (TNF) inhibitors, the importance of early diagnosis has become even more crucial and changes the prognosis for this disease. It has been demonstrated that TNF inhibitors reduce the inflammatory process, therefore preventing structural changes to the joint by 35 percent, on average. This is life changing for the patient.3
Key Diagnostic Criteria and Features of Axial SpA
The criteria for the diagnosis of axial SpA encompass both nonradiographic axial spondyloarthritis and classic ankylosing spondylitis (AS), where there are radiographic findings.1,4 The Assessment of SpondyloArthritis International Society (ASAS) has developed criteria for the classification of axial and peripheral SpA. These criteria incorporate the emerging concept of nonradiographic axial SpA, which refers to patients who have signs and symptoms of axial disease, but lack the radiographic damage to the sacroiliac joints.
Classification Criteria
- Back pain > three months
- Age at onset < 45 years
- Sacroiliitis on imaging (X-ray or MRI) plus one or more SpA features (note list below)
- HLA-B27 protein plus two or more other SpA features
Features of SpA
- Inflammatory back pain
- Arthritis
- Enthesitis (head)
- Uveitis
- Dactylitis
- Psoriasis
- Crohn's disease
- Good response to NSAIDs
- Family history of SpA
- HLA-B27 protein
- Elevated C-reactive protein
Unfortunately, these criteria also end up including other inflammatory autoimmune diseases. Therefore, they are continuing to undergo revision.
SpA and Inflammatory Back Pain
SpA patients often turn to chiropractors for treatment, as they experience chronic back pain. One must remember that inflammatory back pain (IBP) is different from mechanical / degenerative back pain in that onset is usually insidious, not relieved by rest; which is just the opposite of mechanical back pain.
Clinical Symptoms Associated With Inflammatory Back Pain
- Onset of pain is usually under 35 years of age and is insidious.
- Pain persists for more than three months (i.e., it is chronic).
- Pain and stiffness worsen with immobility, especially at night and early morning.
- Pain and stiffness tend to ease with physical activity and exercise.
- NSAIDs are effective in relieving pain and stiffness in most patients.
Note that inflammatory back pain occurs in 70-80 percent of patients with ankylosing spondylitis and is one of the first clinical symptoms.5 Up to 15 percent of patients with AS experience symptoms before the age of 16.6
MRI of the sacroiliac joints has become extremely useful in diagnosing patients with early disease. It is important to emphasize, however, that MRI protocols routinely used in the evaluation of low back pain have a low sensitivity for the detection of inflammation, and unfortunately, often will have negative findings. Close communication between the radiologist and clinician is required to obtain the best possible results when referring these patients for imaging.6
Managing the AS Patient and How Chiropractors Can Contribute
An important development is that new treatment is available for early disease. In 13 clinical trials of five different tumor necrosis factor (TNF) inhibitors, rapid, profound and sustained improvement was obtained in both objective and subjective indicators of disease activity and patient functioning. I don't know anything about TNF inhibitors, but if you are interested, check out references 8-9.
Presently, the guidelines for AS management have been issued by expert panels in Europe, the U.S. and Canada.10-12 Since there is no cure for AS presently, treatment goals include reducing symptoms, improving and maintaining spinal flexibility and normal posture, reducing functional limitations, maintaining the ability to work and decreasing the complications associated with the disease.
These patients need to be managed by a clinical team, with the rheumatologist as the key clinician. Chiropractors can contribute greatly to maintaining spinal flexibility, normal posture and function. However, we need to document this information. There are several tools for assessing disease activity and outcome in ankylosing spondylitis which are widely used today.
We may be the first clinician these patients seek out for treatment. Let's not be the ones to miss this disease, especially when it presents without the typical radiographic findings.
References
- Taurog, JD, Avneesh, C, Colbert R. Ankylosing spondylitis and axial spondyloarthritis. NEJM, 2016;374:26;2563-2574.
- Feldtkeller E, Rudwaleit M, Zeidler H. Easy probability estimation of the diagnosis of early axial spondyloarthritis by summing up scores. Rheumatology, 2013;52:1648-1650.
- Dougados M, et al. Symptomatic efficacy of Etanercept and its effects on objective signs of inflammation in early nonradiographic axial spondyloarthritis: a multicenter, randomized, double-blind, placebo-controlled trial. Arthritis Rheumatol, 2014;66:2091-2102.
- Wang R, Gabriel SE, Ward MM. Progression of patients with non-radiographic axial spondyloarthritis to ankylosing spondylitis: a population-based cohort study. Arthritis Rheumatol, 2016;68:1415-1421.
- van den Berg R, de Hooge M, Rudwaleit M, et al. ASAS modification of the Berlin algorithm for diagnosing axial spondyloarthritis: results from the SPondyloArthritis Caught Early (SPACE)-cohort and from the Assessment of SpondyloArthritis international Society (ASAS)-cohort. Ann Rheum Dis, 2013;72:1646-1653.
- Colbert RA. Classification of juvenile spondyloarthritis: enthesitis-related arthritis and beyond. Nat Rev Rheumatol, 2010;6:477-485.
- Larbi A, Viala P, Molinari N, et al. Assessment of MRI abnormalities of the sacroiliac joints and their ability to predict axial spondyloarthritis: a retrospective pilot study on 110 patients. Skeletal Radiol, 2014;43:351-358.
- Callhoff J, et al. Efficacy of TNFa blockers in patients with ankylosing spondylitis and non-radiographic axial spondyloarthritis: a meta-analysis. Ann Rheum Dis, 2015;74:1241-1248
- Deodhar A, Reveille JD, van den Bosch F, et al. The concept of axial spondyloarthritis: joint statement of the Spondyloarthritis Research and Treatment Network and the Assessment of SpondyloArthritis International Society in response to the US Food and Drug Administration's comments and concerns. Arthritis Rheumatol, 2014;66:2649-2656.
- Braun J, van den Berg R, Baraliakos X, et al. 2010 Update of the ASAS/EULAR recommendations for the management of ankylosing spondylitis. Ann Rheum Dis, 2011;70:896-904.
- Ward MM, Deodhar A, Akl EA, et al. American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network 2015 recommendations for the treatment of ankylosing spondylitis and nonradiographic axial spondyloarthritis. Arthritis Rheumatol, 2016;68:282-298.
- Rohekar S, Chan J, Tse SM, et al. 2014 Update of the Canadian Rheumatology Association/Spondyloarthritis Research Consortium of Canada treatment recommendations for the management of spondyloarthritis. II. specific management recommendations. J Rheumatol, 2015;42:665-681.
Resources / Tools
