Ankylosing Spondylitis: Symptoms, Affected Areas & Systemic Effects

What Is Ankylosing Spondylitis (AS)?

Ankylosing spondylitis is a chronic inflammatory arthritis primarily affecting the axial skeleton (spine and sacroiliac joints). It causes pain, stiffness, swelling, and over time, can lead to bone fusion (ankylosis), resulting in a rigid, inflexible spine. It's part of the spondyloarthritis family and has a strong genetic link (HLA-B27).

Commonly Affected Areas

• Spine: Chronic back pain and stiffness, worse with rest, better with activity. Progressive fusion of vertebrae can lead to "bamboo spine" and loss of mobility.
• Sacroiliac (SI) Joints: Low back and buttock pain, often alternating sides. Hallmark of early AS.
• Hips: Pain, stiffness, limited range of motion; potential cartilage and bone damage leading to secondary osteoarthritis.
• Shoulders: Pain and stiffness; possible joint damage and frozen shoulder.
• Knees: Pain, swelling; possible asymmetric arthritis.
• Entheses: Inflammation where tendons/ligaments attach to bone (heel/Achilles, ribs/costochondritis).

Systemic Involvement

AS is not just joint disease. Inflammation can affect:

• Eyes: Acute anterior uveitis (40% lifetime risk).
• Heart: Aortic inflammation, aortic valve regurgitation, conduction abnormalities.
• Lungs: Upper lobe fibrosis, restricted chest expansion from costovertebral joint fusion.
• Bowel: Association with inflammatory bowel disease (Crohn's, ulcerative colitis).
• Skin: Psoriasis comorbidity.
• Fatigue: Systemic inflammation causes profound, persistent fatigue.

Key Takeaway

Early diagnosis (often delayed 5–10 years) and aggressive management (NSAIDs, biologics, physical therapy) are vital to slow progression, preserve mobility, maintain posture, and protect organ function. Rheumatologist-led care is essential.