I. Calin Criteria (inflammatory back pain)
Four out of 5 must be present:
- Age <40
- Back pain >3 months
- Insidious onset
- Improvement with exercise
- Early morning stiffness.
II. Rudwaleit criteria (axial spondyloarthropathy)
A positive likelihood ratio of 3.7 is achieved if 2 of 4 criteria are present and increases to 12.4 if 3 of 4 criteria are present:
- Morning stiffness >30 minutes
- Improvement in back pain with exercise but not with rest
- Awakening in the second half of the night because of back pain
- Alternating buttock pain.
III. Modified New York criteria for classification
Definite AS if criterion 4 and any one of the other criteria are fulfilled.
- Low back pain of at least 3 months' duration that is improved by exercise and not relieved by rest.
- Limited lumbar spinal motion in sagittal and frontal planes.
- Chest expansion decreased relative to normal values for sex and age.
- Bilateral sacroiliitis grade 2 to 4, or unilateral sacroiliitis grade 3 or 4.
IV. European Spondyloarthropathy Study Group (ESSG) criteria
Inflammatory spinal pain or synovitis is:
• Asymmetrical or
• Predominantly in the lower limbs
and 1 or more of the following:
- Alternate buttock pain
- Enthesitis (inflammation of the tendon or ligament attachments to bone)
- Positive FHx spondyloarthropathy
- Inflammatory bowel disease
- Urethritis or cervicitis or acute diarrhoea occurring within 1 month before arthritis.
Diagnosis of spondyloarthropathy with 6 or more points:
- Inflammatory back pain (1 point)
- Unilateral buttock pain (1 point)
- Alternating buttock pain (2 points)
- Enthesitis (inflammation of the tendon or ligament attachments to bone) (2 points)
- Peripheral arthritis (2 points)
- Dactylitis (2 points)
- Acute anterior uveitis (2 points)
- HLA-B27 positive or FHx of spondyloarthropathy (2 points)
- Good response to NSAIDs (2 points).