Exploration of Musculoskeletal Diseases

Table 1. Possible building blocks for the diagnosis of axSpA (based on the ASAS classification criteria)—part 1: early diagnosis

Nr	Feature	Description/Definition	Decision
1	Back pain 1	Chronic ≥ 3 months in people < 45 years of age	Present yes/no
2	Back pain 2	Inflammatory = morning stiffness > 30 minutes, improvement with exercise, no improvement with rest, nocturnal awakening in the 2nd half of the night, insidious onset	At least 3 of those, better 4. Present yes/no
3	Imaging	MRI, X-ray, computed tomography of the sacroiliac joints and/or the spine	Positive findings regarding inflammation and/or structural changes Past or present yes/no
4	Lab test 1	HLA-B27	Present yes/no
5	Lab test 2	C-reactive protein	Elevated yes/no
6	Other musculoskeletal signs of SpA	Peripheral arthritis, enthesitis, dactylitis	Past or present yes/no
7	Extramusculoskeletal signs of SpA	Anterior uveitis, psoriasis, inflammatory bowel disease (Crohn’s disease or ulcerative colitis)	Past or present yes/no
8	History	Positive family history of SpA	Present yes/no
9	Response to therapy	Good response to non-steroidal anti-inflammatory drugs (NSAIDs)	Past or present yes/no
10	Exclusion	Other important reasons for the presenting symptoms (see text: explanations of the individual building blocks for the diagnosis of axSpA)	Absence yes/no

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axSpA: axial spondyloarthritis; ASAS: Assessment of SpondyloArthritis International Society; SpA: spondyloarthritides; Nr: number; MRI: magnetic resonance imaging. For more explanation see the text: explanations of the individual building blocks for the diagnosis of axSpA

Declarations

Author contributions

JB: Conceptualization, Investigation, Writing—original draft. DP: Writing—review & editing, Investigation, Validation. All authors read and approved the submitted version.

Conflicts of interest

Jürgen Braun, who is the Associate Editor of Exploration of Musculoskeletal Diseases, had no involvement in the decision-making or the review process of this manuscript. The other authors declare that they have no conflicts of interest.

Ethical approval

According to the local guidelines, since this is a review and not a study, no ethical approval is needed in Germany.

Consent to participate

All patients in the University Hospital B. Franklin in Berlin give informed consent.

Consent to publication

All patients in the University Hospital B. Franklin in Berlin give informed consent.

Availability of data and materials

The raw data supporting the conclusions of this manuscript can be requested from the corresponding author for appropriate reasons.

Funding

Not applicable.

Copyright

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