Ankylosing Spondylitis

Question 1

What is Ankylosing Spondylitis?

Answer 1

seronegative inflammatory arthropathy affecting preferentially the axial skeletal + large proximal joints

Question 2

Describe the aetiology of Ankylosing Spondylitis

Answer 2

UNKNOWN
> 90% of cases are HLA-B27 positive
Infective triggers + antigen cross-reactivity with self-peptides have been hypothesised

Question 3

Describe the pathophysiology of Ankylosing Spondylitis

Answer 3

Inflammation starts at the entheses
Persistent inflammation leads to reactive new bone formation
Changes begin in the lumbar vertebrae + ascend

Question 4

Describe the epidemiology of Ankylosing Spondylitis

Answer 4

COMMON

Earlier presentation in males

Question 5

List 6 symptoms of Ankylosing Spondylitis

Answer 5

Lower back + sacroiliac pain
Disturbed sleep
Sx of asymmetrical peripheral arthritis
Pleuritic chest pain (due to costovertebral joint involvement)
Heel pain (due to plantar fasciitis)
Non-specific sx (e.g. malaise, fatigue)

Question 6

List 3 signs of Ankylosing Spondylitis

Answer 6

Reduced range of spinal movement (esp. hip rotation)
Reduced lateral spinal flexion
Tenderness over the sacroiliac joints

Question 7

What test can be performed in Ankylosing Spondylitis?

Answer 7

Schobers test
2 fingers placed (parallel at different spinal levels) on pts back ~10 cm apart
Pt is asked to bend over
Distance between the 2 fingers should increase by > 5 cm on forward flexion
Reduced movement suggests AS

Question 8

What 5 extraarticular manifestations are seen in Ankylosing Spondylitis?

Answer 8

Anterior uveitis  
Apical lung fibrosis  
Achilles tendinitis  
Amyloidosis 
Aortic regurgitation

Question 9

What bloods should be taken in Ankylosing Spondylitis?

Answer 9

FBC: anaemia of chronic disease
Rheumatoid factor: NEGATIVE
ESR/CRP: high

Question 10

What is seen on radiographs in Ankylosing Spondylitis?

Answer 10

Bamboo spine

Symmetrical blurring of joint margins of sacroiliac joints

Question 11

What other investigation may be performed in Ankylosing Spondylitis? Why?

Answer 11

CXR: check for apical lung fibrosis

Lung FT: Assess mechanical ventilatory impairment due to kyphosis

Question 12

What are entheses?

Answer 12

Sites where ligaments attach to vertebral bodies

Question 13

What 4 changes are seen in the spine in Ankylosing Spondylitis?

Answer 13

Vertebral bodies become more square
Syndesmophytes
Fusion of syndesmophytes + facet joints
Calcification of anterior + lateral spinal ligaments

Question 14

What are syndesmophytes?

Answer 14

vertical ossifications bridging the margins between adjacent vertebrae
“bamboo vertebrae”

Question 15

List 3 signs seen in later stages of Ankylosing Spondylitis

Answer 15

Thoracic kyphosis
Spinal fusion
Question mark posture

Question 16

List 3 radiological signs seen in later stages of Ankylosing Spondylitis

Answer 16

Erosions
Sclerosis
Sacroiliac joint fusion

Question 17

Describe the pain pattern in ankylosing spondylitis

Answer 17

Worse in the morning
Better with activity
Worse when resting