📘 Clinical Case Quiz: Chronic Back Pain & Sacroiliitis
A 37-year-old man presents with back pain & chest discomfort for 4 months. Pain improves with medication but recurs after stopping. Imaging reveals pulmonary fibrosis and bilateral sacroiliitis.
🧠 History
Inflammatory back pain, morning stiffness, chest discomfort, improvement with NSAIDs, relapse after discontinuation.
🩺 Examination
Reduced spinal mobility, decreased chest expansion, sacroiliac joint tenderness, restricted lumbar flexion.
🔬 Investigations
CXR: Upper zone fibrotic opacity. Pelvic X-ray: Bilateral sacroiliitis. Likely HLA-B27 positive. Raised ESR/CRP.
❓ MCQ Questions
Q1. Most likely diagnosis?
Q2. Genetic marker?
Q3. Best test for spinal mobility?
Q4. NOT a complication?
📚 Answer Explanation
Findings suggest axial spondyloarthritis due to inflammatory back pain, sacroiliitis, and systemic involvement including pulmonary fibrosis.
❌ Why Not Others
RA affects peripheral joints, reactive arthritis follows infection, psoriatic arthritis shows skin/nail changes, and does not fit sacroiliitis pattern.
🧾 5 Brief Case Scenarios
- Young male with morning stiffness & chronic back pain
- Back pain improves with exercise, worsens at rest
- Uveitis with spinal stiffness
- Reduced chest expansion with sacroiliitis
- HLA-B27 positive inflammatory back pain
🧬 Pathophysiology (Simplified)
HLA-B27 triggers immune-mediated enthesitis → sacroiliac inflammation → spinal ossification → bamboo spine formation.
🩺 Physical Examination Pearls
Schober test <5 cm, chest expansion <2.5 cm, reduced lumbar flexion, sacroiliac tenderness.
🔬 Investigations Findings
Bilateral sacroiliitis, syndesmophytes, bamboo spine, raised ESR/CRP.
⚠️ Complications
Spinal fusion, uveitis, aortic regurgitation, restrictive lung disease, osteoporosis.
💊 Management
NSAIDs first line, physiotherapy, TNF-alpha inhibitors (adalimumab, etanercept), lifestyle modification.
🔍 Differential Diagnosis
Mechanical back pain, RA, psoriatic arthritis, DISH, spinal tuberculosis.
⚠️ Clinical Pitfalls
Misdiagnosing as mechanical back pain, delayed imaging, ignoring inflammatory features.
⭐ Clinical Pearls
Inflammatory back pain improves with activity, not rest.
📈 Monitoring & Follow-up
Monitor pain score, spinal mobility, CRP/ESR, lung function, eye symptoms.
📊 Prognosis
Chronic progressive disease but well controlled with early biologic therapy.
❓ FAQ (15)
- What is ankylosing spondylitis? – Chronic inflammatory spine disease.
- Main gene? – HLA-B27.
- Early symptom? – Low back pain.
- Age group? – Young adults.
- Gender? – Male predominance.
- Best imaging? – Pelvic X-ray.
- Curable? – No.
- First line treatment? – NSAIDs.
- Role of exercise? – Essential.
- Smoking effect? – Worsens disease.
- Eye involvement? – Uveitis.
- Cardiac issue? – Aortic regurgitation.
- Lung issue? – Fibrosis.
- Complication? – Bamboo spine.
- Biologic therapy? – TNF inhibitors.
📚 References
Harrison’s Internal Medicine, Oxford Rheumatology Textbook, UpToDate Guidelines.
