What is the best approach to evaluate and manage a patient with ankylosing spondylitis?

Evaluation and Management of Ankylosing Spondylitis

Initial Evaluation

Diagnose ankylosing spondylitis using the modified New York criteria: radiological evidence of sacroiliitis (bilateral grade ≥2 or unilateral grade 3-4) plus at least one clinical criterion. 1

Clinical Criteria to Assess:

• Low back pain and stiffness for >3 months that improves with exercise but is not relieved by rest 1
• Limitation of lumbar spine motion in both sagittal and frontal planes 1
• Limitation of chest expansion relative to normal values for age and sex 1

Baseline Assessment Parameters:

• Pain assessment: Visual analog scale (VAS) for spine pain at night and during the day 2, 1
• Morning stiffness: Duration (up to 120 minutes) and intensity on VAS 1
• Spinal mobility measurements: Modified Schober test, chest expansion, occiput-to-wall distance, and lateral lumbar flexion 2, 1
• Functional status: Bath Ankylosing Spondylitis Functional Index (BASFI) or Dougados Functional Index 2, 1
• Disease activity: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 1
• Peripheral joints: 44-joint count for swollen joints 1
• Enthesitis: Using Maastricht, Berlin, or San Francisco scoring systems 1
• Laboratory: ESR or CRP 2
• Imaging: AP and lateral x-ray of lumbar spine, lateral cervical spine, AP pelvis (sacroiliac and hip joints) 2

Define Active Disease:

Active disease requires disease activity for >4 weeks AND BASDAI >4 (on 0-10 scale), or expert clinical opinion based on history, examination, acute phase reactants, and/or imaging showing rapid progression or continuing inflammation. 1

Management Algorithm

Step 1: Non-Pharmacological Treatment (All Patients)

Initiate patient education and regular exercise immediately—these are cornerstone treatments that must continue throughout the disease course. 2, 3

• Home exercise programs improve function in the short term compared to no intervention 2, 3
• Supervised group physiotherapy is superior to home exercise alone for patient global assessment outcomes 2, 3
• Individual and group physical therapy should be considered based on disease severity 2
• Gentle muscle strengthening focusing on isometric exercises that don't require significant joint movement 3
• Spa therapy provides benefit for physical functioning over 3 months and is cost-effective 2

Step 2: First-Line Pharmacological Treatment

NSAIDs are the first-line drug treatment for all patients with pain and stiffness. 2, 3

• There is level Ib evidence that NSAIDs improve spinal pain, peripheral joint pain, and function over 6 weeks 2, 3
• Continuous NSAID treatment is preferred for patients with persistent active symptomatic disease 4
• For patients with increased gastrointestinal risk: use either non-selective NSAIDs plus gastroprotective agent OR selective COX-2 inhibitor 2, 3

Step 3: Adjuvant Therapy (If NSAIDs Insufficient)

• Analgesics (paracetamol, opioids) may be considered for pain control when NSAIDs are insufficient, contraindicated, or poorly tolerated 2
• Corticosteroid injections directed to local sites of musculoskeletal inflammation may be considered 2
• Do NOT use systemic corticosteroids for axial disease—there is no evidence supporting this 2

Step 4: Peripheral Disease Management

For patients with peripheral arthritis, sulfasalazine may be considered. 2

• There is no evidence for efficacy of DMARDs (including sulfasalazine and methotrexate) for axial disease 2
• DMARDs are not required before initiating anti-TNF therapy for axial disease 2

Step 5: Anti-TNF Therapy (Persistently High Disease Activity)

Anti-TNF treatment should be given to patients with persistently high disease activity despite conventional treatments (NSAIDs and physical therapy). 2, 3, 4

• There is no evidence supporting obligatory use of DMARDs before or concomitant with anti-TNF treatment in patients with axial disease 2
• For patients with concurrent inflammatory bowel disease, use monoclonal antibody anti-TNF agents rather than etanercept 4
• Anti-TNF agents can treat both AS and vasculitic manifestations when present 4

Step 6: Surgical Intervention

Total hip arthroplasty should be considered in patients with refractory pain or disability and radiographic evidence of structural damage, independent of age. 2, 3

• Spinal surgery (corrective osteotomy and stabilization procedures) may be valuable in selected patients with fixed kyphotic deformity or segmental instability 2, 3

Ongoing Monitoring

Monitor disease every 2-6 months depending on symptoms, severity, and drug treatment using patient history, clinical parameters, laboratory tests, and imaging according to the ASAS core set. 2, 3

• Radiographic monitoring is generally not needed more often than once every 2 years 2, 3
• Exception: Syndesmophytes may develop within 6 months in some patients—this is the smallest interval between x-ray examinations 2
• Assessment should evaluate disease activity/inflammation, pain levels, function, disability, structural damage, hip involvement, spinal deformities, and comorbidities 2, 3

Critical Pitfalls to Avoid

• Do not rely solely on imaging without clinical correlation—overreliance on imaging findings without symptoms leads to unnecessary interventions 1
• Do not forget to assess extra-articular manifestations: uveitis, inflammatory bowel disease, and psoriasis 1
• Do not overlook cardiovascular risk and osteoporosis screening in established disease 1
• Do not use systemic corticosteroids for axial disease—there is no supporting evidence 2