Extra-articular manifestations of RA

1. What sort of patients are most likely to have extra-articular manifestations of RA?
*2. What are skin manifestations of RA?
3. What are ocular manifestations of RA?
4. What are pulmonary manifestations of RA?
5. What is Caplan's syndrome?

Answers:
1. RF+, with rheum nodules, severe articular disease, and MHC class HLA DRB1 alleles.
2. SubQ nodules (also seen in gout) are present in 50% of RA patients, forming subQ in bursae and along tendon sheaths, and may be enhanced by methotrexate. There may also be vasculitis lesions such as leukocytoclastic vasculitis and palpable purpura.
3. Keratoconjunctivitis sicca (dry eyes), episcleritis (benign), scleritis (severe inflammation).
4. Interstitial lung disease (fibrosis), pulm fibrosis, pleurisy, bronchiolitis obliterans.
5. Caplan's syndrome is interpulmonary nodules, similar to rheum nodules, associated with RF+ rheum arthritis and pneumoconiosis in coal works.

Joint deformities in RA

1. What is the most common type of atlantoaxial subluxation in RA? What is the maximum atlantoaxial space that is considered normal?
2. What type of foot deformities are seen in RA?
3. What type of ankle deformities are seen in RA?
4. What kind of hip deformities are seen in RA?
5. What kind of shoulder deformities are seen in RA?
6. What kind of elbow deformities are seen in RA?
7. What kind of knee deformities are seen in RA?

Answers:
1. Anterior subluxation is the most common. Any space larger than 2.5-3 mm is abnormal.
2. Hammer toe, claw toe, hallux valgus, lateral deviation of toes.
3. Increased hindfoot pronation, tarsal tunnel syndrome.
4. Protrusio acetabulum, which is inward bulging of acetabulum into pelvic cavity. Arthritis of hip joint.
5. Glenohumeral arthritis with early loss of int rot, effusions, frozen shoulder, rotator cuff injuries.
6. Subcutaneous nodules, olecranon bursitis, flexion deformities, ulnar neuropathies.
7. Loss of full knee extesnion, quad atrophy, Baker's cysts.

Wrist manifestations of RA

1. What is the cause of carpal bones rotating in a zig-zig fashion?
2. What is the piano key sign?
3. What is resorptive arthropathy?

Answers:
1. Caused by ligament laxity: proximal row rotates volarly, distal row rotates dorsally.
2. Proliferating synovium leads to rupture or destruction of ulnar collateral ligament, so there is floating of the ulnar head.
3. Digits are shortened and phalanges appear retracted with skin folds, resulting in telescoping appearance of digits.

Hand deformities in rheumatoid arthritis

*1. What is a Boutonniere's deformity? How is it treated?
2. What is a swan neck deformity? How is it treated?
3. What is the mechanism of ulnar deviation of the fingers? How is it treated?
4. What occurs in tenosynovitis of the flexor tendon sheath?
5. What is a pseudobenediction sign?

Answers:
1. Caused by weakness/rupture of terminal portion of extensor hood resulting in extensors of the PIP slipping and becoming flexors. This causes flexion of the PIP, hyperextension of the DIP and MCP. (Position of finger as if buttoning a button.) Treat with tripoint finger splint.
2. Caused by contracture of intrinsic and deep flexor muscles and tendons of fingers, resulting in flexion contracture of MCP, hyperextension of PIP, and flexion of DIP. Treat with swan neck ring splint.
3. Weakening of ECU, ulnar and radial collateral ligaments, resulting in wrist and finger deviation in the ulnar direction. Treated with ulnar deviation splint.
4. Diffuse swelling of volar surfaces of the phalanges between the joints with grating of flexor tendon sheath.
5. Extensor tendons rupture due to abrasion from rubbing on sharp elevated ulnar styloid, resulting in inability to extend 4th and 5th digits.

Radiographic findings in rheumatoid arthritis

1. What general radiographic findings are seen in RA?
2. What C-spine findings are seen in RA?
3. What are early radiographic findings of RA?
4. What are late radiographic findings of RA?

Answers:
1. Marginal bone erosions, juxta-articular osteopenia.
2. Atlantoaxial subluxation.
3. Soft tissue swelling, increased joint space.
4. Uniform joint space narrowing, axial migration of hip, malalignment and fusion of joints.

Diagnostic criteria for rheumatoid arthritis

*1. What are the 7 diagnostic criteria for RA? How many must be satisfied for diagnosis?
*2. What joints of the hand are usually affected by RA?
3. What lab tests are ordered to assess for RA?
*4. What does the synovial fluid show in RA?
*5. What percentage of RA patients are RF+?
6. What are diseases may show +RF?

Answers:
1. Must satisfy 4/7: morning stiffness >1hr, arthritis of >3 jts, arthritis of at least one joint in hand, symmetric, rheumatoid nodules, RF+, radiographic changes (erosions, bony decalcification, symm jt space narrowing).
2. PIP, MCP, MTP.
3. RF, ESR, CRP, CBC, synovial fluid.
4. Low viscosity, 1000-75,000 WBC (>70% PMN).
5. 85%, often assoc with severe active disease.
6. SLE, scleroderma, Sjogren's, viral, parasitic, bacterial, neoplasms, hyperglobulinemic.

Rheumatoid arthritis

1. What is the definition of RA?
*2. What is a pannus?
3. What is the prevalence and age range of RA?
4. What is the pattern of onset for RA?

Answers:
1. RA is a systemic autoimmune inflammatory disorder resulting in chronic, symmetric erosive synovitis.
2. Pannus is a membrane of granulation tissue that covers the articular cartilage at joint margins containing fibroblasts that destroy periarticular bone and cartilage. It is the most destructive element in RA.
3. 1% of population, 2x as common in females. Age 20-60 years, peak in 4th and 5th decades.
4. Most have insidious onset over weeks to months with fatigue, malaise, morning stiffness, msk pain usually symmetric, and low grade fever.