Ankylosing Spondylitis: Bamboo Spine, HLA-B27 & Rehab MCQs

Ankylosing Spondylitis (AS)

Ankylosing Spondylitis is a seronegative spondyloarthropathy that primarily affects the axial skeleton (Spine and Sacroiliac joints). It leads to fibrosis, calcification, and ossification of ligaments/joints.

1. Pathology

• Target: Enthesis (Insertion of ligament/tendon into bone). Enthesitis is the hallmark.
• Progression: Ascending (Starts in SI joints -> Lumbar -> Thoracic -> Cervical).
• Bamboo Spine: Ossification of the Annulus Fibrosus and longitudinal ligaments creates bony bridges (Syndesmophytes).

2. Clinical Features

• Demographic: Young males (15-30 years).
• Pain: Inflammatory Back Pain (Morning stiffness > 30 mins, Improves with Exercise, Worsens with Rest).
• Posture: Loss of lumbar lordosis, increased thoracic kyphosis ("Question Mark" posture).
• Extra-articular: Uveitis (Eye), Pulmonary fibrosis, Aortitis.

3. Assessment

Schober's Test: Measures lumbar flexion. Mark L5, mark 10cm above. Patient touches toes. Increase < 5cm indicates stiffness.
Chest Expansion: < 2.5cm indicates costovertebral joint involvement.
X-ray: Sacroiliitis (blurring/sclerosis), Squaring of vertebrae, Bamboo spine.

4. Management

• Exercise (Crucial): Extension exercises, Swimming, Posture training. "Motion is Lotion".
• Medical: NSAIDs (Indomethacin), Biologics (TNF-blockers).

25 Practice MCQs

Q1. The genetic marker strongly associated with AS is:

Answer: A). Present in >90% of patients.

Q2. "Bamboo Spine" is caused by the formation of:

Answer: A). Vertical bridging bone. Osteophytes are horizontal (OA).

Q3. The primary site of pathology in AS is the:

Answer: A). Inflammation at tendon/ligament insertion.

Q4. A key clinical feature differentiating AS form mechanical back pain is:

Answer: A). Inflammatory vs Mechanical pattern.

Q5. Schober's Test assesses:

Answer: A). < 5cm expansion is abnormal.

Q6. Which joint is typically the first to be affected?

Answer: A). Often bilateral and symmetrical.

Q7. Seronegative Spondyloarthropathy means:

Answer: A). Distinguishes it from RA.

Q8. "Dagger Sign" on X-ray is due to:

Answer: A). Looks like a dagger running down the center of the spine.

Q9. The most common extra-articular manifestation is:

Answer: A). Red, painful eye.

Q10. Chest expansion is limited due to involvement of:

Answer: A). Leads to restrictive lung pattern.

Q11. Which posture is typical of advanced AS?

Answer: A). "Beggar's Posture" or Question mark spine.

Q12. Squaring of vertebrae is caused by:

Answer: A). Loss of the normal anterior concavity.

Q13. Is AS more common in males or females?

Answer: A). Typically young men.

Q14. "Andersson Lesion" is:

Answer: A). Mimics discitis/infection.

Q15. Management focuses primarily on:

Answer: A). Prevention of flexion deformity is key.

Q16. Which exercise is most beneficial?

Answer: A). Encourages extension and chest expansion.

Q17. Spinal osteotomy (Smith-Petersen) is done for:

Answer: A). "Chin-on-chest" deformity correction.

Q18. Enthesitis is commonly felt at the:

Answer: A). Heel pain is common.

Q19. Are peripheral joints affected?

Answer: A). Hip involvement indicates worse prognosis.

Q20. Occiput-to-Wall distance measures:

Answer: A). Increased distance = increased deformity.

Q21. NSAIDs (e.g., Indomethacin) in AS are:

Answer: A). First line therapy.

Q22. Which biologic agents are effective?

Answer: A). Highly effective for axial disease.

Q23. Fracture of the ankylosed spine is:

Answer: A). The spine breaks like a long bone.

Q24. Sleeping position recommended is:

Answer: A). To prevent flexion contractures.

Q25. "Shiny Corner" sign on MRI represents:

Answer: A). Precedes squaring.