Ankylosing Spondylitis

Question 1

What joints does AS target?

What are the consequences of this?

Answer 1

Sacroiliac
Vertebral column

Inflammatory back pain and stiffness
Can lead to fusion of these joints which results in BAMBOO SPINE presentation on xray

Question 2

Which gene is heavily associated with AS?

Answer 2

HLA B27

Question 3

What is the typical exam presentation of AS?

Answer 3

Young adult male in late teens or 20s with symptoms developing gradually over more than 3 months

Question 4

How might someone with AS present clinically?

Answer 4

Inflammatory lower back pain + stiffness

• worse in mornings
• better on movement
• wake up at night
• > 30 mins morning stiffness

Sacroiliac pain

Peripheral synovitis (hips/shoulders)
-might present with groin pain 

Chest wall pain (costochondral + costovertebral)
-reduced expansion

Extra-articular features:

• uveitis
• enthesitis
• colitis
• aortitis leading to AR

(Symptoms can flare or relapse)

Question 5

What are the systemic associated symptoms of AS?

Answer 5

Weight loss
Fatigue 
Chest pain due to inflammation in costovertebral and coststernal joints
Dactylitis
Anaemia 
Anterior uveitis 
Aortitis 
Heart block due to fibrosis of conductive systems in the heart 
Restrictive lung disease 
Pulmonary fibrosis 
IBD

Question 6

What is the criteria for a AS diagnosis?

What physical test can be done to support the diagnosis of AS? What would be seen normally and what would be seen in AS?

Answer 6

Inflammatory spinal pain >3 months plus 1 (+):

• alternate buttock pain
• sacroiliitis on XR
• enthesopathy
• FH
• psoriasis
• IBD
• urethritis/cervicitis/diarrhoea w/i one month before onset

Schober’s test

• Locate L5 and mark point 10cm above and 5cm below
• Ask patient to bend over and measure the distance between the points
• > 20cm = normal i.e. should increase by 5cm on full flexion
• <20cm = restricted lumbar movement

Question 7

What investigations can be done for AS?

Answer 7

CRP and ESR 
IgA= elevated 
Hb= normocytic anaemia (chronic disease) 
Alk phosphatase= elevated 
HLA B27 genetic test 
X-ray 
Isotope bone scan 
MRI= bone marrow oedema in early disease
USS if enthesitis

Question 8

What X-ray changes are seen in AS?

Answer 8

Sacroiliitis:

• irregularity of SI joint
• erosions
• sclerosis of ileum
• ankyloed SI joint i.e. complete loss of joint space

Bamboo spine
-due to fusion of vertebral bodies via syndesmophytes

Squaring of vertebral bodies

Subchondral sclerosis + erosions

Syndesmophytes= areas of bone growth where ligaments insert into bone (esp at intervertebral joints)

Ossification

Squaring of anterior ligament

Question 9

How can AS be managed medically?

Answer 9

NSAIDs for pain 
DMARDs (disease modifying anti-rheumatic drugs)
-sulphasalazine 
-methotrexate 
-Steroids during flare ups 
-Anti-TNF 

Surgical= hip resurfacing or replacement

Question 10

What conservative management is used for AS?

Answer 10

Physiotherapy 
-hydrotherapy 
Exercise and mobilisation 
Smoking cessation or avoidance
Bisphosphonates for osteoporosis

Question 11

How would you summarise ankylosing spondylitis?

Answer 11

Seronegative spondylo-arthropathy affecting axial skeleton