Ankolysing Spondylitis

Question 1

Define:

Answer 1

• Seronegative chronic inflammatory arthropathy affecting preferentially the axial skeletal and large proximal joints
• Part of a group of conditions termed ‘sero-negative spondyloarthropathies’ –
• Seronegative = rheumatoid factor -v

Question 2

Aetiology/risk factors:

Answer 2

• UNKNOWN
• Strong association with the HLA-B27 gene (> 90% of cases are HLA-B27 positive)
• Infective triggers and antigen cross-reactivity with self-peptides have been hypothesised
• Mainly affects SPINE and SACROILIAC JOINTS
Inflammation starts at the entheses (where ligaments attach to vertebral bodies

Question 3

Epidemiology:

Answer 3

• COMMON
• Earlier presentation in males
• Usually 30yr old males

Question 4

Symptoms:

Answer 4

• Gradual onset
• Lower back and sacroiliac pain
• Disturbed sleep
• Pain pattern
o Worse in the morning
o Better with activity
o Worse when resting
• Progressive loss of spinal movement
• Symptoms of asymmetrical peripheral arthritis
• Pleuritic chest pain (due to costovertebral joint involvement)
• Heel pain (due to plantar fasciitis)
• Non-specific symptoms (e.g. malaise, fatigue)
• Blindness due to acute iritis in 1/3 of patients

Question 5

Signs:

Answer 5

• Reduced lateral spinal flexion
• Schober’s Test
o Two fingers are placed on the patients back about 10 cm apart
o The patient is asked to bend over
o The distance between the two fingers should increase by > 5 cm on forward flexion
o Reduced movement would suggest ankylosing spondylitis
• Tenderness over the sacroiliac joints

LATER STAGES:
o Thoracic kyphosis
o Spinal fusion
o Question mark posture

Question 6

Extra-articular signs:

Answer 6

o	Anterior uveitis 
o	Apical lung fibrosis 
o	Achilles tendinitis 
o	Amyloidosis
o	Aortic regurgitation 
5As

Question 7

Investigations:

Answer 7

o FBC - anaemia of chronic disease
o Rheumatoid factor - negative
o ESR/CRP - high
o HLA B27+ve but this is not diagnostic!!
• Radiographs – MRI most sensitive and better at detecting early disease.

o LATER STAGES:
• Erosions
• Sclerosis

Sacroiliac joint fusion
o CXR - check for apical lung fibrosis
• Lung Function Tests
o Assess mechanical ventilatory impairment due to kyphosis