MUSCULOSKELETAL
ANKYLOSING SPONDYLITIS
Etiology
Autoimmune; strong association with HLA-B27; often triggered by gut or genitourinary infections.
Pathogenesis
Chronic inflammation of sacroiliac joints and spine → progressive ossification and fusion (“bamboo spine”). Enthesitis (inflammation at ligament insertion) common.
Clinical Features
Chronic low back pain and stiffness improving with activity;
reduced spinal mobility; morning stiffness;
possible uveitis and aortic involvement.
Diagnostic Findings
X-ray/MRI: sacroiliitis, bamboo spine.
↑ ESR/CRP
HLA-B27 positive in most cases.
Treatment
First line: NSAIDs, physiotherapy, exercise.
Advanced: TNF or IL-17 inhibitors (biologics).
- Avoid prolonged immobility.