How do you spot inflammatory back pain among mechanical presentations?
Recognising features of axial spondyloarthritis (including ankylosing spondylitis) and when to refer to rheumatology.
Subjective triage
- Back pain starting before age 45 and lasting longer than three months.
- Morning stiffness lasting more than 30 minutes that improves with movement.
- Night pain in the second half of the night, waking the patient.
- Improvement with exercise but not with rest; alternating buttock pain.
- Associated features: uveitis, psoriasis, inflammatory bowel disease, family history, or good response to anti-inflammatories.
Differential dilemma: vs lumbar facet-mediated pain
| Feature | Axial spondyloarthritis vs mechanical back pain | Lumbar facet-mediated pain |
|---|---|---|
| Morning stiffness | Often longer than 30 minutes | Usually brief, easing within minutes |
| Response to activity | Improves with exercise | Aggravated by sustained extension or rotation |
| Night pain | Wakes in the second half of the night | Mainly positional discomfort |
| Wider features | Eye, skin, gut or family history links | None |
Red flags: recognise, screen, refer
Recognise
- Unexplained weight loss, fever or night sweats
- History of cancer
- Thoracic pain with systemic illness
- Severe unremitting night pain
Screen
Ask systematically about inflammatory features and extra-articular conditions; these are often missed for years.
Refer
Suspected axial spondyloarthritis should be referred to rheumatology for assessment. Serious pathology red flags follow urgent pathways.
The clinical reasoning chain
- 1
History
28-year-old with 6 months of low back pain, an hour of morning stiffness, better after exercise.
- 2
Pattern
Several inflammatory back pain features cluster together.
- 3
Objective finding
Reduced spinal mobility; mechanical tests do not explain the pattern.
- 4
Diagnostic decision
Possible axial spondyloarthritis: refer to rheumatology while keeping the patient active.
Quick reference FAQ
Is a normal X-ray reassuring for axial spondyloarthritis?
No. Early disease may not show on X-ray. Diagnosis is made by rheumatology using clinical features, blood tests and imaging such as MRI.
Should physiotherapists keep treating while awaiting referral?
Yes. Exercise and staying active are central to management, alongside medical care.
Why is the delay to diagnosis so long?
Symptoms are often attributed to mechanical back pain. Asking about inflammatory features in every young adult with persistent back pain helps.