Immunology · Year 2 · from Immunology
Case 2: Rheumatoid Arthritis
Patient Demographics
- Age: 45 years old
- Sex: Female
- Ethnicity: Caucasian
Chief Complaint
Painful, swollen joints in hands for 6 months
History of Present Illness
A 45-year-old woman presents with a 6-month history of joint pain and swelling primarily affecting her hands. She reports morning stiffness lasting 2-3 hours that improves with activity. The symptoms began insidiously, first affecting her fingers, and have progressively involved her wrists and feet. She has noticed difficulty making a fist and has had to remove her rings due to finger swelling. She also reports fatigue and a 5-pound unintentional weight loss.
Past Medical History
- 20-pack-year smoking history (quit 5 years ago)
- No prior joint problems
Family History
- Sister with rheumatoid arthritis
- Mother with hypothyroidism
Physical Examination
- General: Well-appearing woman with obvious hand deformities
- Vital Signs: Normal
- Hands: Symmetric swelling and tenderness of MCPs (2nd-5th bilaterally) and PIPs; warmth over affected joints; boggy synovium on palpation; decreased grip strength
- Wrists: Bilateral swelling and tenderness with limited extension
- Feet: Tenderness at MTPs bilaterally (squeeze test positive)
- No subcutaneous nodules palpated
Laboratory Workup
| Test | Result | Reference Range |
|---|---|---|
| ESR | 58 mm/hr | 0-20 mm/hr |
| CRP | 3.8 mg/dL | <0.5 mg/dL |
| Rheumatoid Factor | 186 IU/mL | <14 IU/mL |
| Anti-CCP antibody | >250 U/mL | <20 U/mL |
| ANA | 1:80 (speckled) | Negative |
| CBC | Normal | -- |
| Hand X-rays | Periarticular osteopenia, joint space narrowing MCPs, early erosions at 2nd and 3rd MCP | Normal |
Diagnosis
Seropositive Rheumatoid Arthritis with early erosive disease
Discussion
Rheumatoid arthritis is a chronic inflammatory joint disease characterized by symmetric polyarthritis with progressive joint destruction:
Pathogenesis:
- Genetic susceptibility: HLA-DR4 "shared epitope" association
- Environmental trigger: Smoking promotes citrullination of proteins
- Autoimmunity: Anti-CCP antibodies target citrullinated proteins
- Synovial inflammation: T cells, B cells, macrophages produce TNF-alpha, IL-1, IL-6
- Pannus formation: Proliferating synovium invades and destroys cartilage and bone
Why is anti-CCP important?
- More specific for RA than rheumatoid factor (95% vs 70%)
- Predicts erosive disease and worse prognosis
- Can be positive years before clinical disease onset
- Helps distinguish RA from other causes of RF positivity
Joint involvement pattern in RA:
- Affected: MCPs, PIPs, wrists, MTPs (symmetric)
- Spared: DIPs (unlike osteoarthritis and psoriatic arthritis)
Extra-articular manifestations (not yet present):
- Rheumatoid nodules (elbows, lungs)
- Interstitial lung disease
- Felty syndrome (splenomegaly, neutropenia)
- Cardiovascular disease (accelerated atherosclerosis)
Treatment
- Early aggressive treatment: Treat-to-target strategy (low disease activity or remission)
- Conventional DMARDs: Methotrexate first-line (anchor drug)
- Biologic DMARDs if inadequate response:
- TNF inhibitors (adalimumab, etanercept)
- Other options: Abatacept (costimulation blockade), Rituximab (B cell depletion), JAK inhibitors
- Bridging therapy: Low-dose prednisone while DMARDs take effect
- Monitoring: Disease activity scores, inflammatory markers, imaging for erosion progression
- Cardiovascular risk management: Aggressive risk factor modification