Ankylosing spondylitis

Headline
Etiology Chronic inflammation of spine+sacroiliac joints
Epidemiology typically male <age 40. 88% are HLA-B27 +ve
Clinical presentation Low back pain radiating from sacroiliac joints to hips, morning stiffness; enthesitis/costochondritis
↓ lumbar lordosis+ ↑ thoracic kyphosis including thoracic expansion

Extra-articular signs: iritis; anterior uveitis
Pathogenesis
Diagnostic investigations Clinical diagnosis
Pelvic/spine XR: bamboo spine, fusion of SI joints, apparent fusion of spinous processes (calcification of interspinous+ supraspinous ligaments)
Management Assess impact with BASDAI
➥ NSAIDs are first line (remember ~PPIs)
➥ With rheum referral: TNF α blockers
➥ If uncontrolled (etanercept, adalimumab), intra-articular steroid injections
➥ Surgical mx: hip replacement
➥ Prognosis worse if: onset<16 years, early hip involvement, ESR>30, poor response to ~NSAIDs
Prevention