Ankylosing spondylitis (AS), now more broadly classified as radiographic axial spondyloarthritis (r-axSpA), is a chronic inflammatory arthritis primarily affect…
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Ankylosing spondylitis (AS), now more broadly classified as radiographic axial spondyloarthritis (r-axSpA), is a chronic inflammatory arthritis primarily affecting the sacroiliac joints and spine. It is characterized by sacroiliitis, progressive spinal inflammation, and potentially fusion (ankylosis). AS affects approximately 0.5–1% of the US population, with male predominance (3:1 male-to-female ratio) and onset typically before age 45. The HLA-B27 antigen is present in >90% of AS patients. The availability of TNF inhibitors and IL-17A inhibitors has transformed management, reducing pain, improving function, and potentially slowing structural progression.
This information is for educational purposes only. Always consult a qualified healthcare professional for diagnosis and personalized treatment.
Chronic low back pain: inflammatory in character — worse at night, morning stiffness >1 hour, improves with exercise, worsens with rest
Sacroiliac joint pain radiating to buttocks
Reduced spinal mobility (forward flexion, lateral rotation)
Neck pain and stiffness (cervical spine involvement in advanced disease)
Chest pain and reduced chest expansion (costovertebral and costosternal joint involvement)
Peripheral arthritis (hips — most commonly involved peripheral joint; knees, ankles)
Enthesitis: inflammation at tendon/ligament insertion sites (Achilles, plantar fascia, patellar tendon)
Dactylitis ('sausage digit')
Acute anterior uveitis (eye): unilateral painful red eye, photophobia (occurs in 25–40% lifetime)
Fatigue (major contributor to impaired quality of life)
Clinical criteria: chronic LBP >3 months, onset <45 years, inflammatory back pain features
Pelvic X-ray: sacroiliitis (bilateral grade ≥2, or unilateral grade ≥3) — modified New York criteria for r-axSpA
MRI sacroiliac joints: bone marrow edema (active sacroiliitis) — can detect before X-ray changes (non-radiographic axSpA)
HLA-B27 testing — supportive but not diagnostic alone
CRP/ESR: elevated in ~60% (normal in 40%)
Spinal mobility measures: BASMI (Bath Ankylosing Spondylitis Metrology Index), Schober test, occiput-to-wall distance, chest expansion
Disease activity: BASDAI (Bath AS Disease Activity Index), ASDAS (AS Disease Activity Score)
ASAS classification criteria for axial spondyloarthritis
NSAIDs (Naproxen, Indomethacin, Diclofenac, Celecoxib)
First-line therapy. Full anti-inflammatory doses. Continuous use superior to on-demand in active AS (potential structural sparing effect debated). Indomethacin traditionally most used. Monitor GI, CV, renal.
TNF Inhibitors (Adalimumab, Etanercept, Infliximab, Certolizumab)
Standard biologic for NSAID-inadequate responders. All TNF inhibitors have similar efficacy in AS. Certolizumab is pregnancy-compatible. Adalimumab, golimumab, infliximab approved for AS + IBD.
Secukinumab (Cosentyx)
IL-17A inhibitor. Superior radiographic sparing vs. TNF inhibitors in some studies (MEASURE trials). Option for TNF-failure, or as first biologic. Also effective for uveitis and IBD-associated AS (less preferred if active IBD).
Ixekizumab (Taltz)
IL-17A inhibitor. COAST program established efficacy in biologic-naive and TNF-inadequate responders. Monthly maintenance dosing after loading. Similar efficacy to secukinumab.
JAK Inhibitors (Tofacitinib, Upadacitinib, Filgotinib)
Oral option for refractory AS. Upadacitinib 15 mg daily (SELECT-AXIS trial). Tofacitinib 5 mg BID. Boxed warning: malignancy, thromboembolism, cardiovascular events — use after biologic failure in appropriate patients.
Daily physical therapy and exercise — most important non-pharmacological intervention; maintains flexibility and posture
Swimming and water exercise — excellent for spinal mobility with low impact
Maintain upright posture (hard firm mattress, sleeping on back, no pillow or thin pillow)
Smoking cessation — smoking accelerates spinal damage and reduces biologic response
NSAIDs: take with food; consider PPI for GI protection
Uveitis: prompt ophthalmology evaluation at first sign of red eye (can threaten vision if untreated)
IBD monitoring: report new bowel symptoms
Vaccinations before biologics: influenza, pneumococcal, hepatitis B, shingles (Shingrix)
Prognosis
AS is a lifelong condition but functional outcomes have improved dramatically with biologic therapy. TNF inhibitors and IL-17A inhibitors achieve ASAS40 response in 50–65% of patients. Complete radiographic non-progression ('bridging the gap') has been shown with secukinumab vs. placebo over 4 years. Hip joint involvement is the strongest predictor of functional disability. A minority of patients require total hip replacement. Most patients on modern therapy maintain meaningful functional capacity and work productivity. Extra-articular manifestations (uveitis, IBD, psoriasis) require coordinated multi-specialty management.
Ankylosing Spondylitis is a medical condition classified under Rheumatology. Ankylosing spondylitis (AS), now more broadly classified as radiographic axial spondyloarthritis (r-axSpA), is a chronic inflammatory arthritis primarily affecting the sacroiliac joints and spine. It is characterized by sacroiliitis, progressive spinal inflammation, and potentially fusion (ankylosis). Understanding Ankylosing Spondylitis is essential for patients, families, and healthcare providers to ensure timely diagnosis, appropriate treatment, and optimal outcomes.
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The information on this page is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult your doctor or a qualified healthcare provider with any questions about a medical condition.