Rheum - RA

Question 1

describe the pathophysiology of RA

Answer 1

1. Autoantibodies Rh and anti-CCP bind to their targets - Fc domain of altered IgG and citrullnated proteins - forming immune complexes…
2. stimulates complement and immune response: pro-inflammatory cytokine production (TNFa, IL-1, IL-6) in synovial joints…
3. synovial cells proliferate and form a pannus…
4. damages cartilage and soft tissue, and causes bone erosion

Question 2

what is a pannus?

Answer 2

thick, swollen synovial membrane with granulation tissue

Question 3

describe symptoms caused by RA

Answer 3

1. joint pain - insidious, symmetrical, typically affecting small joints of hands and feet (often spares distal IP joints)
2. joint stiffness - lasting >1hr, typically in early morning or after inactivity
3. constitutional symptoms, e.g. fatigue, fever, sweats, weight loss

Question 4

describe the signs caused by RA

Answer 4

1. joint swelling and heat
2. muscle wasting and tendon rupture
3. hand deformities - ulnar deviation, swan neck and Boutonniere’s deformity of fingers, Z deformity of thumb, piano key deformity of wrist

Question 5

suggest possible extra-articular manifestations of RA

Answer 5

1. rheumatoid nodules - in skin, eyes, lungs, heart and occasionally vocal cords
2. skin: rash, leg ulcers
3. eyes: secondary Sjogren’s, scleritis, episcleritis
4. resp. system: pleural effusions, ILD
5. CVS: pericardial involvement, valvulitis, myocardial fibrosis, increased risk of atherosclerosis
6. liver: mild hepatomegaly and abnormal transaminases common, increased hepcidin production causing anaemia

Question 6

name the 4 hallmark X-ray findings for RA

Answer 6

1. joint space narrowing
2. marginal erosions
3. soft tissue swelling
4. juxta-articular osteoporosis

Question 7

how is RA progression/control monitored?

Answer 7

DAS28 score - composite score derived from 4 measures, looking at 28 joints:

i) no. of swollen joints (/28)
ii) no. of tender joints (/28)
iii) ESR or CRP level
iv) Pt’s ‘global assessment of health’ (indicated by marking a 10cm line between v. good and v. bad)

> 5.1 implies active disease
<3.2 implies low disease activity
<2.6 implies remission

Question 8

what is the 1st line Tx for newly diagnosed RA? what other drugs can be added?

Answer 8

Within 3 mths of persistent symptom onset, Pt should be started on:
1. methotrexate +
2. at least 1 other DMARD (e.g. sulfasalazine, hydroxychloroquine) +
3. short-term corticosteroid, e.g. prednisolone
When sustained and satisfactory levels of disease control achieved, try reducing dose

Can also add:

• analgesics, e.g. paracetamol or codeine
• NSAIDS, e.g. ibuprofen, diclofenac, naproxen (+ PPI)

Question 9

which drugs are recommended if 1st line Tx is not effective?

Answer 9

Biologics, e.g. infliximab, etanercept, rituximab, tocilizumab

Question 10

what is Felty syndrome?

Answer 10

RA + splenomegaly + granulocytopenia (can lead to life-threatening infections)

Question 11

what is the main differential for DVT in an RA pt with leg swelling?

Answer 11

ruptured baker cyst