What are the most likely causes of low back pain and stiffness that resolve with jogging or walking, but do not respond to Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)?

Most Likely Diagnosis: Inflammatory Spondyloarthropathy (Axial Spondyloarthritis)

The clinical presentation of low back pain and stiffness that improves with exercise (jogging/walking for 30 minutes) but does not respond to NSAIDs is highly suggestive of inflammatory spondyloarthropathy, particularly axial spondyloarthritis associated with inflammatory bowel disease or ankylosing spondylitis. 1

Key Diagnostic Features Present

This patient demonstrates the classic inflammatory back pain pattern:

• Pain improved with exercise and not relieved by rest - this is the hallmark feature that distinguishes inflammatory from mechanical back pain 1
• Morning stiffness lasting more than 30 minutes (implied by the need for 30 minutes of activity to resolve symptoms) 1
• Age consideration - if under 45 years with symptoms lasting more than 3 months, this significantly increases suspicion for axial spondyloarthropathy 1

Why NSAID Non-Response is Significant

The lack of response to NSAIDs is somewhat atypical but important:

• NSAIDs are typically the initial treatment for axial spondyloarthropathy and usually provide relief 1
• However, NSAID non-response does not exclude inflammatory arthropathy - it may indicate more severe disease requiring earlier progression to anti-TNF therapy 1
• This distinguishes it from mechanical low back pain, where NSAIDs show only modest benefit anyway 1

Critical Next Steps

Immediate diagnostic workup should include:

• MRI scanning (sagittal images of cervicothoracic and thoracolumbar regions with T1 and STIR sequences, plus coronal/oblique sacroiliac joints with T1 and STIR) - plain radiography will miss most early disease 1
• HLA-B27 testing - though note this is less often positive in IBD-associated axial arthropathy 1
• Rheumatology referral for specialist assessment 1

Alternative Considerations (Less Likely)

Spinal stenosis is less likely because:

• Neurogenic claudication from stenosis typically worsens with walking/exercise (opposite pattern) 2
• Pain usually improves with rest and forward flexion, not with continued activity 2

Mechanical low back pain is unlikely because:

• Mechanical pain typically worsens with activity and improves with rest (opposite of this presentation) 3
• The dramatic improvement with sustained exercise is not characteristic 3

Management Implications

If inflammatory spondyloarthropathy is confirmed:

• Physiotherapy and specialist assessment can prevent long-term disability - early diagnosis is vital as diagnosis is often very delayed 1
• NSAIDs remain first-line despite initial non-response - they are more effective than simple analgesia for axial arthropathy 1
• Early progression to anti-TNF therapy is often necessary as sulfasalazine and methotrexate are not effective for axial disease 1
• Simple analgesia is preferable to NSAIDs for safety, but NSAIDs are more effective for this specific condition 1

Common Pitfall to Avoid

Do not dismiss this as simple mechanical back pain based on the young age or absence of red flags - the exercise-responsive pattern with morning stiffness is pathognomonic for inflammatory arthropathy and requires specific investigation with MRI, not plain films 1