Arthritis of the spine, <30y, male, HLA-B27 (PAIR)
Etiology
- Infections and molecular mimicry (T2 hypersensitivity reaction) may play a role – Yersina, Klebsiella, salmonella, shigella
Clinical features
- Early – episodic inflam of sacro-iliac joints, gluteal pain and stiffness, fatigue
- Pain relieved by exercise, retention of lumbar lordosis, paraspinal muscle wasting
- Schober test – spinal stiffness (<5cm = stiffness)
- Chest pain (costochondral inflam), asymmetric peripheral joints, hip involvement
- Anterior uveitis – HLA B27 association
- Assessment via Bath AS disease activity index
Diagnosis
- ESR/CRP raised, HLA testing
- XR – sacro-iliac bone erosion, vertebral rim blurring (thoracolumbar), bony spurs ( Enthesitis ) bamboo spine (calcification)
- MRI – w/ contrast, seen before XR and enthesitis
Treatment
- Exercise, long acting NSAID
- Methotrexate [25mg/week] – effective for peripheral not spinal
Etanercept [50mg/week s.c] and adalimumab
