Diagnosis: Ankylosing Spondylitis
This 32-year-old male has ankylosing spondylitis based on his inflammatory back pain pattern (morning stiffness, improvement with exercise, night awakening), young age of onset, sacroiliac joint tenderness, loss of lumbar lordosis, and elevated inflammatory markers. 1, 2
Clinical Features Supporting Diagnosis
The patient demonstrates the pathognomonic features of inflammatory spondyloarthropathy that distinguish it from mechanical low back pain:
- Improvement with exercise (basketball, gym) is the hallmark distinguishing feature—mechanical pain worsens with activity while inflammatory pain improves 1, 2
- Morning stiffness and awakening during the second part of the night are characteristic of ankylosing spondylitis 1, 2
- Age < 45 years with chronic back pain > 3 months meets screening criteria 2
- Alternating buttock pain (left hip involvement) is a specific feature 2, 1
- Loss of lumbar lordosis and restricted spinal mobility indicate disease progression 2
- Sacroiliac joint tenderness on examination is highly suggestive 2
Laboratory Findings
- Elevated ESR (70 mm/hr) and CRP (10 mg/L) support active inflammation, though these are elevated in only 50% of AS patients 2, 3
- Anemia of chronic disease (normocytic anemia with Hb 100 g/L, normal MCV) is consistent with chronic inflammatory disease 4
Immediate Diagnostic Work-Up Required
Order HLA-B27 testing immediately—this has 90% sensitivity and provides a post-test probability of 32%, making it the ideal screening test 2
Obtain imaging of sacroiliac joints:
- Plain radiographs of pelvis (AP view) and lumbar spine (AP and lateral) as initial imaging 2, 5
- If radiographs are negative but clinical suspicion remains high (which it is), proceed directly to MRI of sacroiliac joints with STIR sequences—MRI detects early inflammatory changes before radiographic sacroiliitis develops 2, 3
Treatment Algorithm
First-Line: NSAIDs + Physical Therapy
Initiate continuous high-dose NSAID therapy immediately (not just as-needed)—this is the first-line treatment and recent evidence shows regular use slows radiographic progression 2, 3
- Prescribe full-dose NSAIDs continuously (e.g., naproxen 500mg twice daily or indomethacin 75mg twice daily) 2
- Do NOT use systemic glucocorticoids—these are strongly recommended against in AS 2
Refer to physical therapy immediately—this is a strong recommendation with proven benefit 2
- Individual or group physical therapy programs focusing on spinal mobility exercises 2
- Home exercise programs emphasizing posture maintenance and stretching 2
- Regular supervised exercise has superior outcomes for patient global assessment 2
Second-Line: TNF Inhibitors
If inadequate response to NSAIDs after 4 weeks, initiate TNF inhibitor therapy—this is strongly recommended for active AS despite NSAID treatment 2
- TNF inhibitor monoclonal antibodies (infliximab, adalimumab, golimumab) are preferred over etanercept given the need to rule out subclinical inflammatory bowel disease in spondyloarthropathy patients 2
- More than two-thirds of AS patients have inadequate response to NSAIDs alone and require biologic therapy 3
Medications to AVOID
- Sulfasalazine and methotrexate are NOT effective for axial disease (only for peripheral arthritis) 2
- Systemic glucocorticoids are strongly contraindicated 2
Critical Pitfalls to Avoid
Do not delay rheumatology referral—the average time to diagnosis of AS is often years, leading to preventable disability 6, 3
Smoking cessation is mandatory—the patient's 4-6 cigarettes/day significantly worsens AS prognosis and disease progression 5
Monitor for extra-articular manifestations:
- Anterior uveitis (occurs in 25-40% of AS patients) 5
- Inflammatory bowel disease 2
- Cardiovascular complications including aortitis 4
Assess for spinal fracture risk—patients with AS have increased fracture risk even with minor trauma due to spinal rigidity 5