SpA features (11). Note: Inflammatory back pain has 8 subquestions to ask to. Following SpA features were negative unless otherwise stated Inflammatory back pain (age <45yr, duration > 3 months, insidious onset, stiffness > 30 min, improvement with exercise, no improvement with rest, awakening from pain especially in the second half of the night with improvement on arising, alternating buttock pain) (2 or more suspicious; 4 or more considered diagnostic for Inflammatory back pain) Arthritis Enthesitis (heel) Uveitis Dactylitis Psoriasis Crohn’s disease/ulcerative colitis Good response to NSAIDs Family history for SpA HLA-B27 Elevated CRP 25 yo with 2 yr history of suspicious inflammatory low back pain (3/8 features), uveitis, psoriasis, elevated CRP, positive HLA-B27 X ray negative MRI negative Applying ASAS criteria: Given age < 45, duration > 3 months, with HLA B27+, and has > 2 SpA features (Uveitis, Psoriasis, elevated CRP) meets classification criteria for SpA. But this criterion is 83 % sensitive and only 84% specific. Hence, a false positive is included as AS if we were to use this for diagnosis. Hence, instead, if we use the NEJM paper algorithm, Does not have definitive radiographic SI, next Fulfills 3 SpA features (Uveitis, Psoriasis, elevated CRP), because it is 2-3 SpA features Check for HLAB27 - which is positive, Yet does not have compelling features, hence consider MRI (note, if had compelling clinical features, will have SpA) (note: if had 0,1 SpA features, even with compelling clinical features, one will need MRI) (if the 4 or more SpA features were present, then even in the absence of compelling clinical features, we will diagnose with AS even without the need of MRI given HLA B27 is positive) MRI done does not show any SI -hence his disease is not consistent with a diagnosis of AS Hence, this would have been a false positive case of a SpA using ASAS criteria if used for diagnosis. Spondyloarthopathies
Common C/F
1. Reactive Arthritis
2. Ankylosing Spondylitis
4. Enteropathic Arthritis (IBD associated) Clinical Trials on Psoriatic arthritis
Ankylosing Spondylitis
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