B3.023 Rheumatoid Arthritis

Question 1

non inflammatory arthritis

Answer 1

osteoarthritis

Question 2

types of inflammatory arthritis

Answer 2

rheumatoid
psoriatic
Crohn’s

Question 3

definition of osteoarthritis

Answer 3

mechanical derangement of joint

“wear and tear”

Question 4

cause of primary osteoarthritis

Answer 4

aging

Question 5

causes of secondary osteoarthritis

Answer 5

trauma

genetic conditions

Question 6

most common places of osteoarthritis involvement

Answer 6

knee
hip
hands (PIPs, DIPs, MCPs)

Question 7

rheumatoid arthritis epidemiology

Answer 7

prevalence approx. 1%
-lower in Africa, higher in native americans
women 2-3x more likely than men
peak onset 50-75

Question 8

describe the clinical presentation of RA

Answer 8

symmetric polyarticular involvement
upper and lower extremities
can affect most joints but spares DIPs
most common joints involved first include MCPs, PIPs, wrists, and MTPs

Question 9

distinguish between morning stiffness associated with RA and OA

Answer 9

RA usually > 1 hour

OA 30 min or less

Question 10

how do swollen joints feel early in RA?

Answer 10

fluid filled and boggy

Question 11

what are some classic joint changes associated with late stages of RA?

Answer 11

ulnar deviation at MCPs in setting of subluxation
Z deformity
swan neck (extension of PIP and flexion of DIP)
boutonniere deformity (flexion of PIP and extension of DIP)

Question 12

what are some clues to distinguish OA?

Answer 12

associated with activity
short morning stiffness
DIPs affected
bony appearing changes
no ulnar deviation

Question 13

which type of arthritis is associated with extraarticular manifestations

Answer 13

RA is a systemic inflammatory disease not limited to just the joints

Question 14

pulmonary extraarticular manifestation

Answer 14

pleural disease (effusions and pleurisy)
pulmonary nodules
interstitial lung disease (extensive honeycombing on CT due to scarring and destruction)

Question 15

cardiac extraarticular manifestation

Answer 15

pericarditis and pericardial effusion (similar to lupus)
nodules (can affect conduction and valves)
myocarditis
accelerated CAD

Question 16

skin extraarticular manifestations

Answer 16

rheumatoid nodule
rheumatoid vasculitis (inflammation of blood vessels leads to occlusion and ischemia)

Question 17

eye extraarticular manifestations

Answer 17

secondary Sjogren’s/Keratoconjunctivits sicca (inflammation of salivary glands, dryness of eyes and mouth)
episcleritis and scleritis
corneal melt

Question 18

hematological extraarticular manifestations

Answer 18

Felty’s syndrome - splenomegaly, leukopenia, and RA

Question 19

what are some nonspecific changes the body may undergo related to inflammation in RA?

Answer 19

anemia of chronic disease
thrombocytosis
leukocytosis

Question 20

neurologic extraarticular manifestations

Answer 20

entrapment neuropathy (carpal tunnel syndrome, due to swelling)
spinal cord compression related to spine involvement such as C1-C2 (can lead to paralysis)

Question 21

discuss the genetic findings of twin studies related to RA

Answer 21

monozygotic: 15-30%
dizygotic: 5%
general population: 1%

Question 22

what is the shared epitope of RA?

Answer 22

highly similar AA sequence in alleles in HLA-DRB1 locus

strongest genetic link to RA

Question 23

what is HLA-DRB1 involved in?

Answer 23

MHC molecule-based antigen presentation
self peptide selection
T-cell repertoire

Question 24

what are some environmental factors that may contribute to RA?

Answer 24

silica (caplan’s syndrome)
smoking
periodontal disease
gut microbiome

Question 25

which type of Th cell is an important link with the innate immune system?

Answer 25

Th17

Question 26

how are autoantibodies related to the innate immune system?

Answer 26

can activate macrophages

Question 27

which type of leukocyte activate downstream cells that mediate damage seen clinically in RA?

Answer 27

macrophages

Question 28

how does RA appear on an H&E stain?

Answer 28

fibrovascular tissue protrudes from inflamed synovium into the articular cartilage

Question 29

what is the roles of osteoclasts in RA?

Answer 29

ultimately lead to bone destruction resulting in erosions and joint deformities

Question 30

which lab tests assist with diagnosis of RA?

Answer 30

rheumatoid factor (RF) anti-cyclic citrullinated peptide (CCP) anti-nuclear antibody (ANA)

Question 31

which lab tests assist with monitoring RA disease activity?

Answer 31

erythrocyte sedimentation rate (ESR) | c-reactive protein (CRP)

Question 32

which lab tests assist with medication monitoring in RA?

Answer 32

CBC with dif creatinine AST, ALT

Question 33

rheumatoid factor

Answer 33

autoantibodies that recognize determinants of the Fc portion of IgG most commonly IgM against Fc portion of IgG sens: 70-80% spec: 70% (increases w age and associated with other diseases)

Question 34

anti-cyclic citrullinated peptide (CCP)

Answer 34

post translational modification to arginine performed by antibody peptidylarginine deiminase (PAD) to form citrulline sense: 70% spec: 95%

Question 35

why is citrullination an issue?

Answer 35

citrullinated proteins fit with the HLA-DRB1 epitope on APCs, stimulating antibody production if you then get citrullinated proteins in your joints, they complex with the Abs stimulating complement activation/ an inflammatory response

Question 36

how is smoking thought to be related to RA?

Answer 36

smoking promotes PAD enzymes and citrullination in the lungs

Question 37

what is seronegative RA?

Answer 37

people with RA who test negative for both RF and CCP | 20% of patients

Question 38

seropositive RA

Answer 38

associated with worse prognosis

Question 39

what about positive RF and CCP but no RA?

Answer 39

patients could be early in disease development or may not develop disease at all

Question 40

synovial fluid findings in RA

Answer 40

inflammatory synovial fluid cell count | 5000-50000 cells w predomninant neutrophils

Question 41

radiographic findings in RA

Answer 41

``` periarticular osteopenia (bones near joints get darkers) symmetric joint space loss marginal erosions soft tissue swelling no new bone formation ```

Question 42

is MRI commonly used to diagnose RA?

Answer 42

no, not usually worth additional cost to see minimally different images

Question 43

ultrasound findings of RA

Answer 43

high power Doppler signal consistent with active disease | gray scale synovial hypertrophy

Question 44

when do you use ultrasound in RA patients?

Answer 44

prognosis more than for diagnosis

Question 45

radiographic findings in RA versus OA

Answer 45

RA: erosions, periostitis, joint space narrowing OA: joint space narrowing, osteophytes, subchondral sclerosis