Shared features of Spondyloarthritis

Question 1

Diagnosis of Spondyloarthritis

Answer 1

Age <40yrs at onset
Insidious onset
Pain improves with exercise
No improvement with rest
Pain at night with improvement upon moving

IBP if 4/5

Question 2

Features of associated peripheral arthritis

Answer 2

Oligoarticular - usually <5 joints

Asymmetric

Usually lower limb joints

Question 3

Other important joint features

Answer 3

Enthesititis:

• Inflammation of ligament, tendon and joint capsule insertions
• Affects the axial and peripheral skeleton at points of great physical stress

Dactylitis:

• Diffuse fusiform swelling of the toes and fingers
• Due to swelling of the inflammation of the flexor tendon sheath

Question 4

Extra-Articular features

Answer 4

Anterior Uveitis:

• Acute onset, unilateral, painful eye
• Photophobia and blurring of vision
• redness at the scleral-corneal junction

Keratoderma blennorhagicum

Circinate balanitis

Mucosal lesions

Question 5

Joint Imaging Changes

Answer 5

X-ray - loss of joint space, erosions, ankylosis, fusion

MRI - Bone oedema, osteitis, erosions, sclerosis, ankylosis

Question 6

Shared genetic Risk factors?

Answer 6

HLA-B27

• Normal Class 1 MHC molecule
• <5% of HLA-B27 positive individuals get SpA but 85-95% of AS patients have HLA-B27

ERAP1