Case Report: A 27-year-old woman with inflammatory back pain
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The presented MRI images are suggestive for inflammation of the sacroiliac joints of a 27 years old woman. She suffers from inflammatory back pain (IBP) for more than 3 months which defines as:
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Calin’s criteria for IBP [1] |
Berlin criteria for IBP [2] |
ASAS IBP criteria mnemonic for criteria “iPAIN” [3] |
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Age at onset < 40 yr |
Morning stiffness of > 30 min duration |
Insidious onset |
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Duration of back pain > 3 mo |
Improvement in back pain with exercise but not with rest |
Pain at night (with improvement upon getting up) |
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Insidious onset |
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Morning stiffness |
Nocturnal awakening (second half of the night only) |
Age at onset < 40 yr |
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Improvement with exercise |
Alternating buttock pain |
Improvement with exercise |
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No improvement with rest |
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Requires the presence of four of five criteria |
The sensitivity is 70% specificity 81% if two of the four criteria are fulfilled |
The sensitivity is 77.0% and specificity 91.7% if at least four out of five criteria are fulfilled |
Imaging of the sacroiliac joints (SIJ) and the spine has an important role in the diagnosis, classification and monitoring for patients with SpA.
X-ray of SIJ
Sacroiliitis on conventional radiography became an important diagnostic tool and was given an outstanding role in the development of classification criteria in 1961 and modified NY criteria in 1984.
Bilateral grade ≥ 2 or unilateral grade ≥ 3 sacroiliitis are considered critical for the diagnosis of AS. However, radiographic sacroiliitis reflects structural changes which may appear late in the disease process at least in a subset of patients. Thus, it has low specificity especially for patients at the early stages of the disease.
In case of negative radiographs
According to a recently published consensus of the Arthritis Subcommittee of the ESSR, in case of negative radiographs in patients with a suspicion of SpA, MRI is mandatory to look for early inflammatory lesions [4]. Both the clinical and the imaging arm are considered equally important for the classification criteria of ASAS. [5,6]
In combination with at least one other feature of SpA, sacroiliitis, either diagnosed by radiographs (radiographic stage) or diagnosed by MRI (nonradiographic stage), is referred to as the imaging arm. HLA-B27-positivity, in combination with at least two other features of SpA, is referred to as the clinical arm. This underlines the importance of imaging.
1. Calin A, Porta J, Fries JF, Schurman DJ. Clinical history as a screening test for ankylosing spondylitis. JAMA 1977; 237: 2613–4.
2. Sieper, J., et al. "New criteria for inflammatory back pain in patients with chronic back pain: a real patient exercise by experts from the Assessment of SpondyloArthritis international Society (ASAS)." Annals of the rheumatic diseases 68.6 (2009): 784-788.
3. Rudwaleit, Martin, et al. "Inflammatory back pain in ankylosing spondylitis: a reassessment of the clinical history for application as classification and diagnostic criteria." Arthritis & Rheumatism 54.2 (2006): 569-578.
4. Schueller-Weidekamm, Claudia, et al. "Imaging and interpretation of axial spondylarthritis: the radiologist's perspective--consensus of the Arthritis Subcommittee of the ESSR." Seminars in musculoskeletal radiology. Vol. 18. No. 3. 2014.
5. Sieper J, Rudwaleit M, Baraliakos X, et al. The Assessment of SpondyloArthritis international Society (ASAS) handbook: a guide to assess spondyloarthritis. Ann Rheum Dis 2009;68(Suppl 2): ii1–ii44
Tags: axial SpA, radiography