Ankylosing Spondylitis

Question 1

Joints affected in AS

Answer 1

Sacroiliac joints

Vertebral column

causes pain and stiffness in these joints - can progress to fusion of the spine and sacroiliac joints (“bamboo spine”)

Question 2

Link with HLA B27

Answer 2

90% of patients with AS have the HLA B27 gene

2% of people with the gene will get AS - around 20% if they have a first degree relative that is affected

Question 3

Typical presentation of AS

Answer 3

Male - late teens or 20s

Symptoms develop gradually > 3 months

Lower back pain
Stiffness
Sacroiliac pain

Worse with rest and improves with movement
Worse at night and in the morning takes at least 30 minutes for the stiffness to improve

Symptoms can fluctuate with “flares”

Question 4

Key complication of AS

Answer 4

Vertebral fractures

Question 5

Associations with AS

Answer 5

weight loss

Fatigue

Anaemia

Anterior uveitis

Chest pain related to costovertebral and costosternal joints

Aortitis is inflammation of the aorta

Heart block can be caused by fibrosis of the heart’s conductive system

Restrictive lung disease can be caused by restricted chest wall movement

Pulmonary fibrosis at the upper lobes - 1% of AS patients

IBD

Enthesitis

Dactylitis

Question 6

What is enthesitis?

Answer 6

Inflammation of the entheses

Tendons or ligaments insert in to bone

Can cause problems such as plantar fasciitis and achilles tendonitis

Question 7

Schober’s Test

Answer 7

L5 vertebrae

10cm above and 5cm below

Distance with them bending forwards is less than 20cm = supports diagnosis of AS

Question 8

Investigations in AS

Answer 8

CRP and ESR

HLA B27 genetic test

Xray of the spine and sacrum

MRI of the spine can show bone marrow oedema early in the disease before there are any xray changes

Question 9

Xray changes

Answer 9

Fusion of the facet, sacroiliac and costovertebral joints

Bamboo spine

Ossification of the ligaments, discs and joints. This is where these structures turn to bone

Squaring of the vertebral bodies

Subchondral sclerosis and erosions

Syndesmophytes

Question 10

What are syndesmophytes?

Answer 10

Areas of bone growth where the ligaments insert into the bone

Occur related to the ligaments supporting the intervertebral joints

Question 11

Management of AS

Answer 11

NSAIDs

Steroids

Anti-TNF medications such as etanercept/ Mab

Secukinumab is a monoclonal antibody against interleukin-17. It is recommended by NICE if the response to NSAIDS and TNF inhibitors is inadequate.

Question 12

Further management of AS (6)

Answer 12

Physiotherapy

Exercise and mobilisation

Avoid smoking

Bisphosphonates to treat osteoporosis

Treatment of complications

Surgery is occasionally required for deformities to the spine or other joints