7. Rheumatoid Arthritis

Question 1

what key feature distinguishes RA from OA

Answer 1

RA is an autoimmune disease

Question 2

how is inflammation in the joints presented in RA

Answer 2

symmetrical in presentation and develops simultaneously

Question 3

name 3 similarities between RA and OA

Answer 3

• both located in joints
• no cure for either
• not fatal conditions but can decrease quality of life

Question 4

what is the difference between RA and OA in terms of the area it affects

Answer 4

OA primarily affects cartilage
RA primarily affects the lining of the joint (synovial membrane)

Question 5

which has a shorter timescale: RA or OA

Answer 5

RA

Question 6

how long does RA take to develop

Answer 6

a few months, but can be within a week in 15% of cases

Question 7

name 4 symptoms of RA

Answer 7

symmetrical joint swelling
morning stiffness
fatigue
Raynaud’s phenomenon

Question 8

describe 3 methods of how RA is diagnosed

Answer 8

observation of symptoms

detection of rheumatoid factor

X-ray

Question 9

at what stage would an Xray only provide a diagnosis

Answer 9

at late stages - where there is joint erosion

Question 10

what is rheumatoid factor

Answer 10

a group of autoantibodies to the Fc portion of IgG

Question 11

what joint is affected the most in RA

Answer 11

finger joints

Question 12

name two joints on the fingers affected by RA

Answer 12

proximal interphalangeal joint

distal interphalangeal joint

Question 13

what are synoviocytes

Answer 13

fibroblast like cells

Question 14

what is the role of synoviocytes

Answer 14

cells responsible for the production of synovial fluid components, absorption from the joint cavity and for blood/synovial fluid exchange

Question 15

describe the positioning of normal synoviocytes

Answer 15

line the fluid filled synovial membrane

Question 16

what causes the abnormal proliferation of synoviocytes

Answer 16

inflammatory processes

Question 17

what does the extensive growth of synoviocytes result in

Answer 17

uncontrolled growth = vascularisation and extensive angiogenesis

Question 18

describe what happens to the synovial lining when cells start to grow

Answer 18

it eventually connects with the cartilage on the surface of the tibial plaque and causes damage to the cartilage

Question 19

what facilitates bone erosion

Answer 19

imbalance of osteoclasts and osteoblasts prevents the normal turnover of bone = destruction

Question 20

what aggrecan damaging protein is also elevated in RA, what does this do?

Answer 20

matrix metalloproteinase

• breaks down aggrecan, no water can be held in the cartilage = cartilage damage

Question 21

which is more common: OA or RA

Answer 21

OA - less than 1% of the population suffer with RA

Question 22

is RA sex biased?

Answer 22

yes - women are 2-3x more likely to suffer RA

Question 23

name some ethnic groups with a lower prevalence of RA

Answer 23

Chinese and japanese

Question 24

what is the typical age of onset for RA

Answer 24

40-60 years old

Question 25

how long does RA take to develop

Answer 25

typically over several months but in 15% of cases it can happen within 1 week

Question 26

what gene is associated with 30% of the risk of RA

Answer 26

HLA-DRB1

Question 27

what is the role of HLA-DRB1

Answer 27

encodes part of the HLA complex which is involved in distinguishing self from non-self

Question 28

name a polymorphism that can act as a risk factor for several autoimmune diseases

Answer 28

PTPN22

Question 29

name 2 environmental risk factors for RA

Answer 29

higher BMI - over 25 increases the risk by 15% smoking

Question 30

how much increased is the risk for RA in males who smoke compared to females

Answer 30

males who smoke 2X increased risk females = 1.3X increased risk

Question 31

what does the scientific community postulate to be a trigger of RA

Answer 31

both viral and bacterial infections

Question 32

what is a medical mystery in RA

Answer 32

some people get spontaneously better!!

Question 33

what does SADMD stand for

Answer 33

slow acting disease-modifying drugs

Question 34

give an example of SADMD

Answer 34

gold injections

Question 35

give an example of an immunosuppressant

Answer 35

methotrexate

Question 36

what is the risk of methotrexate

Answer 36

it is not targeted immune suppression - can lead patients vulnerable to infection and can increase the risk of tumour growth

Question 37

describe the use of corticosteroids in RA

Answer 37

effective short term relief from symptoms potent anti-inflammatory drugs effectiveness is short term!!

Question 38

what is the problem with corticosteroids

Answer 38

they are addictive and effectiveness is short term

Question 39

how does infliximab work?

Answer 39

- soluble TNF alpha is prevented from binding and creating a pro-inflammatory cascade - transmembrane TNF alpha is marked for cell lysis via complement cascade - increases IL-10 to create an anti-inflammatory microenvironment