Ankylosing Spondylitis

What Is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a type of inflammatory arthritis that primarily affects the spine and sacroiliac joints. Over time, inflammation can cause new bone to form, leading to spinal fusion (ankylosis). It typically begins in young adults.¹

Symptoms²

Spinal

• Chronic low back pain (>3 months)
• Morning stiffness (>30 minutes)
• Improves with exercise, not rest
• Night pain (waking second half of night)
• Buttock pain (alternating)
• Progressive loss of spinal mobility

Extra-Spinal

• Peripheral joint arthritis
• Enthesitis (heel, Achilles)
• Eye inflammation (uveitis)
• Fatigue

Risk Factors

• HLA-B27 gene (most patients carry it)
• Family history
• Male sex (more severe disease)
• Age of onset typically 17-45

Diagnosis

• Clinical features
• X-ray or MRI of sacroiliac joints
• Elevated inflammatory markers
• HLA-B27 testing

Treatment³

Exercise (Essential)

• Daily stretching and mobility exercises
• Posture exercises
• Swimming, water therapy
• Physical therapy

Medications

• NSAIDs (first-line, often very effective)
• TNF inhibitors (if NSAIDs insufficient)
• IL-17 inhibitors
• JAK inhibitors

Prognosis

With modern treatment, most people maintain function. Early diagnosis and treatment prevent progression.

References

1. Sieper J, Poddubnyy D. Axial spondyloarthritis. Lancet. 2017;390(10089):73-84.
2. Braun J, Sieper J. Ankylosing spondylitis. Lancet. 2007;369(9570):1379-1390.
3. Ward MM, Deodhar A, Gensler LS, et al. 2019 Update of the American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network recommendations. Arthritis Rheumatol. 2019;71(10):1599-1613.