Rheumatoid Arthritis

Question 1

What is rheumatoid arthritis (RA)?

Answer 1

A chronic autoimmune inflammatory disease primarily affecting synovial joints, leading to progressive joint damage and systemic complications.

Question 2

What is the hallmark feature of RA?

Answer 2

Symmetrical polyarthritis, typically involving small joints (e.g., hands, wrists, feet).

Question 3

Who is most commonly affected by RA?

Answer 3

Women (3:1 female-to-male ratio).

Peak onset: 30–50 years of age.

Question 4

What are the key genetic risk factors for RA?

Answer 4

HLA-DR4 and HLA-DR1 alleles.

Polymorphisms in PTPN22 and other immune-regulatory genes.

Question 5

What environmental factors are associated with RA?

Answer 5

Smoking: Strongest modifiable risk factor.

Periodontal infections (e.g., Porphyromonas gingivalis).

Silica exposure.

Question 6

What is the key immunologic mechanism in RA?

Answer 6

Autoimmune activation leads to synovial inflammation, pannus formation, and joint destruction.

Question 7

What role do autoantibodies play in RA?

Answer 7

Rheumatoid factor (RF): Autoantibody against IgG Fc.

Anti-cyclic citrullinated peptide (anti-CCP) antibodies: Specific for RA, targeting citrullinated proteins.

Question 8

What inflammatory cytokines are involved in RA?

Answer 8

Tumor necrosis factor-alpha (TNF-α).

Interleukin-1 (IL-1).

Interleukin-6 (IL-6).

Question 9

What are the hallmark joint features of RA?

Answer 9

Symmetrical joint involvement.

Morning stiffness lasting >1 hour.

Swelling, warmth, and tenderness of affected joints.

Question 10

What joints are typically affected early in RA?

Answer 10

Small joints: MCPs, PIPs, wrists, MTPs.

Sparing of DIP joints (distinguishes RA from osteoarthritis).

Question 11

What are common deformities in advanced RA?

Answer 11

Swan neck deformity: Hyperextension of PIP, flexion of DIP.

Boutonnière deformity: Flexion of PIP, hyperextension of DIP.

Ulnar deviation of the fingers.

Question 12

What are common extra-articular features of RA?

Answer 12

Rheumatoid nodules (subcutaneous, over extensor surfaces).

Lung: Interstitial lung disease, pleuritis, pulmonary nodules.

Cardiovascular: Increased risk of atherosclerosis, pericarditis.

Hematologic: Anemia of chronic disease, Felty syndrome (RA, splenomegaly, neutropenia).

Neurologic: Peripheral neuropathy, atlantoaxial subluxation.

Eyes: Scleritis, episcleritis, keratoconjunctivitis sicca (dry eye).

Question 13

How is RA diagnosed?

Answer 13

Based on clinical, serologic, and imaging criteria (ACR/EULAR classification).

Question 14

What laboratory findings support a diagnosis of RA?

Answer 14

Positive RF (present in ~70–80% of cases).

Positive anti-CCP antibodies (high specificity).

Elevated ESR and CRP (markers of inflammation).

Question 15

What imaging findings are characteristic of RA?

Answer 15

Early: Soft tissue swelling, periarticular osteopenia.

Late: Joint erosions, subluxation, and joint space narrowing.

Question 16

What is the cornerstone of RA treatment?

Answer 16

Disease-modifying antirheumatic drugs (DMARDs).

Question 17

What is the first-line DMARD for RA?

Answer 17

Methotrexate, used as monotherapy or in combination.

Question 18

What are other conventional DMARDs?

Answer 18

Leflunomide.

Sulfasalazine.

Hydroxychloroquine.

Question 19

What are biologic therapies used in RA?

Answer 19

TNF inhibitors: Adalimumab, infliximab, etanercept.

IL-6 inhibitors: Tocilizumab.

Costimulation blockers: Abatacept.

B-cell depletion: Rituximab.

Question 20

What role do corticosteroids play in RA?

Answer 20

Low-dose corticosteroids are used for short-term symptom relief during flares or while awaiting DMARD efficacy.

Question 21

What factors indicate a poor prognosis in RA?

Answer 21

Early joint erosions.

High levels of RF or anti-CCP antibodies.

Extra-articular involvement.

High disease activity at diagnosis.

Question 22

How does osteoarthritis differ from RA?

Answer 22

Joint involvement: OA affects weight-bearing joints (knees, hips) and DIP joints; RA typically involves MCPs, PIPs, and wrists.

Symmetry: OA is often asymmetric, while RA is symmetrical.

Morning stiffness: OA stiffness lasts <30 minutes; RA stiffness lasts >1 hour.

Inflammatory signs: OA has minimal inflammation; RA involves warmth, swelling, and tenderness.

Radiographic findings:
- OA: Joint space narrowing, subchondral sclerosis, osteophytes.
- RA: Periarticular osteopenia, erosions.

Serology: Negative RF and anti-CCP in OA.

Question 23

How is psoriatic arthritis distinguished from RA?

Answer 23

Skin findings: PsA is associated with psoriatic plaques or nail pitting, absent in RA.

Joint pattern: PsA can involve DIP joints and is often asymmetric; RA spares DIP joints and is symmetrical.

Enthesitis: PsA often causes inflammation where tendons attach to bone (e.g., Achilles tendon); uncommon in RA.

Radiographic findings: PsA shows “pencil-in-cup” deformities and periostitis; RA shows joint erosions and periarticular osteopenia.

Serology: RF and anti-CCP are typically negative in PsA.

Question 24

How does SLE differ from RA?

Answer 24

Systemic features: SLE has a wide range of systemic symptoms (rash, renal, hematologic, and CNS involvement), while RA predominantly affects joints.

Joint involvement: SLE causes non-erosive, migratory arthritis; RA causes erosive arthritis.

Skin findings: SLE has a malar rash, discoid rash, and photosensitivity, absent in RA.

Serology:
- SLE: Positive ANA, anti-dsDNA, anti-Smith antibodies.
- RA: Positive RF and anti-CCP.

Radiographic findings: No erosions in SLE; erosions are typical in RA.

Question 25

How is reactive arthritis differentiated from RA?

Answer 25

Preceding infection: ReA follows infections (e.g., gastrointestinal or genitourinary infections); RA has no such trigger.

Joint pattern: ReA is typically asymmetric and affects large joints, especially in the lower extremities; RA is symmetrical and affects small joints.

Systemic symptoms: ReA can involve uveitis, conjunctivitis, and urethritis (“can’t see, can’t pee, can’t climb a tree”), which are not features of RA.

Serology: Negative RF and anti-CCP in ReA.

HLA-B27 association: Strongly associated with ReA but not with RA.