Spondyloarthropathy

Basics

Description

A group of rheumatic diseases characterized by axial and/or peripheral arthritis and enthesitis (inflammation at the bony insertion of tendons and ligaments)

Enthesitis-related arthritis
Ankylosing spondylitis (AS)
Psoriatic arthritis
Inflammatory bowel disease–associated arthropathy
Reactive arthritis

Epidemiology

Spondyloarthritis accounts for 15–20% of juvenile arthritis or more.
Nonradiographic axial spondyloarthritis (male = female)
AS typically affects adolescent boys (male-to-female ratio is 2 to 3:1).

Prevalence

Prevalence of AS mirrors that of HLA-B27 in a population

European descent 8% HLA-B27+ and 0.5% AS

Risk Factors

Genetics

HLA-B27 associated
Risk of developing ERA with HLA-B27 is approximately 1–3%. Usually, there is a family history of a male relative with the disease.
HLA-B27–positive with a family history of AS have a 10-fold increased risk of AS compared to HLA-B27–positive person with no family history.

Pathophysiology

Inflammatory synovitis of joints and inflammation at sites of ligament and tendon attachment to bone (entheses).
Progression to ankylosis is a result of calcification of the anterior and posterior longitudinal ligaments of the spine.

Etiology

Autoimmune or autoinflammatory arthritis of unknown etiology, likely multifactorial
Microbiome may play a role in disease.

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