Seronegative spondyloarthropathies - ankylosing spondylitis
Description
- Chronic inflammatory disease of the axial skeleton and entheses, HLA-B27-associated, RF-negative ("seronegative")
- Inflammation at the enthesis (tendon/ligament insertion), not the synovium - the defining lesion of the whole SpA family
- -> erosion, then new bone formation (syndesmophyte, ankylosis)
- *Uniquely destructive AND proliferative* - contrast RA, which only erodes
The axial SpA spectrum
| Radiographic sacroiliitis | ||
|---|---|---|
| Non-radiographic axSpA (nr-axSpA) | Absent - MRI bone marrow oedema only | Same symptom burden and same treatment response; F:M ~1:1 |
| Ankylosing spondylitis (r-axSpA) | Present - modified New York criteria | Male predominant |
- These are a continuum, not separate diseases; only some nr-axSpA progresses to radiographic disease
The wider spondyloarthritis family
- Ankylosing spondylitis / axSpA
- Psoriatic arthritis
- Reactive arthritis
- Enteropathic arthritis (IBD-associated)
- Undifferentiated SpA
- Shared features: HLA-B27, enthesitis, dactylitis, uveitis, asymmetrical lower-limb oligoarthritis, family clustering
Clinical features
- Inflammatory back pain with insidious onset before age 45
- Peripheral: hip arthritis is the commonest peripheral joint (~30%, groin/thigh pain), asymmetrical lower-limb oligoarthritis
- Enthesitis - Achilles insertion, plantar fascia, iliac crest, greater trochanter
- Dactylitis ("sausage digit")
6 more sections, plus exam facts
Premium unlocks every note across every specialty, and the full exam fact library behind it.
Get premium access