Spondyloarthritis

Question 1

What is spondyloarthropathy

Answer 1

Any joint disease of the vertebral column

Question 2

What is spondyloarthritis with inflammation called

Answer 2

Axial spondyloarthiritis

Question 3

Where is HLA B27 expressed

Answer 3

on all cells except RBCs (it is a tissue type - you are either HLA B27 + or -ve)

Question 4

What encodes HLA B27

Answer 4

MHCs on chromosome 6

Question 5

What tissue type usually gets Axial spondyloarthiritis

Answer 5

B27 -ve

B27 +ve do not get these

Question 6

Why is B27 linked to spondyloarthritis (3)

Answer 6

1. Infection -> immune response -> infectious agents have peptides similar to B27 -> auto-immune response triggered against HLA B27
2. Mis-folding theory
3. HLA B27 heavy chain homodimer hypothesis

Question 7

What is the HLA B27 misfiling theory

Answer 7

1. Unfolded HLA-B27 proteins accumulate in ER
2. A pro inflammatory response called the ER unfolded protein response occurs
3. IL-23 is released by macrophages which activate T-helper cells
4. T-helper cells release IL-17 which causes an inflammation cascade

Question 8

What pro-inflammatory mediators are released in response to IL-17

Answer 8

IL-6
IL-1
TNF-alpha

Question 9

What is the HLA B27 heavy chain homodimer hypothesis

Answer 9

B27 heavy chains can form stable dimers which dimerise and accumulate in the ER

This initiates ERUPR

Heavy chains and dimers bind to NK cells causing survival of more pro inflammatory leukocytes

Question 10

Clinical features of SpA

Answer 10

1. Inflammatory arthritis of axial skeleton causing fusion of vertebrae (people look hunched over)
2. Enthesitis (inflammation of junction between ligament/tendon and bone in heel)
3. Iritis (inflammation of anterior chamber of the eye)
4. Peripheral arthritis (large joints)
5. Skin psoriasis)

SPINEACHE 
S-sausage digit
P - Psoriasis
I - Inflammatory back pain 
N - NSAID good response
E - Enthesitis
A - Arthritis
C - Crohn's/elevated CRP (can be normal at times)
H - HLA B27
E - Eye (iritis)

Question 11

What is ankylosing spondylitis

Answer 11

Inflammatory arthritis of spine and rib cage leading to new bone formation and fusion of joints

Question 12

When is ankylosing spondylitis seen

Answer 12

Late teen years/20s

Question 13

What people have the worst prognosis for ankylosing spondylitis

Answer 13

1. Male
2. Smokers
3. B27 +ve
4. Syndesmophytes
5. High CRP

Question 14

What are syndesmophwytes

Answer 14

Boney growth originating in a ligament (of a spine in patients with AS)

Question 15

What are romans lesions

Answer 15

Syndemophytes in the anterior vertebral corners

Question 16

Consequence of sarcolitis in ankylosing spondylitis

Answer 16

Erosions

Loss of joint space

Question 17

What would be seen in an MRI positive for AS

Answer 17

1. Subchondral periarticular bone marrow oedema

2. Acute sacrolitis

Question 18

What happens in the advanced disease of AS

Answer 18

1. Kyphosis of thoracic and cervical spine

Patient can’t look ahead while walking

Question 19

What is the proposed structural damage in ankylosing spondylitis

Answer 19

Inflammation
Erosive damage repair
New bone formation

Question 20

Outline the criteria that defines the Inflammatory back pain felt in AS (most people have back pain, why is this so different)

Answer 20

1. Onset younger than 40
2. Improves with excersise
3. Insidious onset
4. Pain at night
5. Morning stiffness

Question 21

What is the non-radiographic stage of AS

Answer 21

1. Back pain and sacrolitis seen on MRI

MRI diagnosis= non-radiographic

Question 22

What is the radiographic stage of SpA

Answer 22

1. Back pain
2. Radiographic sacrolitis
3. Syndesmophytes seen

Question 23

What is the classification criteria for diagnosing axial spondyloarthritis

Answer 23

(in patients with more than 3 months back pain and less than 45 years old):
1. Sacroilitis on imagine + 1Spa Feature (IBP, arthritis, psoriasis, good response to NSAIDs etc)

2. HLA-B27 +ve
   plus 2 or more SpA features

Question 24

What is seen on imaging when sacroilitis is present

Answer 24

1. Inflammation seen on MRI

Question 25

How is ankylosing spondylitis treated

Answer 25

TNFi (blockers):
Infliximab and adalimumab
DMARDs (disease-modifying antiarrythmic drugs)
NSAIDs