Rheumatoid Arthritis Diagnosis

Study Notes

Rheumatoid Arthritis (RA) must be distinguished from symmetrical seronegative spondyloarthropathies.
Severe RA can resemble a type of psoriatic arthritis known as "arthritis mutilans."

A positive serology is now a requirement for RA diagnosis.
Joint involvement scoring:
- 1 large joint: 1 point
- 2-10 large joints: 2 points
- 1-3 small joints: 1 point
- 4-10 small joints: 2 points

Classic radiographic signs include:
- Periarticular osteopenia
- Joint space narrowing
- Juxtaarticular erosions
- Erosions of the ulnar styloids
Early signs often first seen in the feet, particularly at the fifth metatarsophalangeal joint.

Rheumatoid Factor (RF):
- Antibodies targeting the Fc region of IgG; poor specificity for RA.
- Associated conditions: SLE, Sjögren's syndrome, viral infections (HCV, EBV, etc.).
- Only about 50% of RA patients are RF positive at onset; up to 20% may remain negative.
- High titers can indicate an aggressive disease course.
Anti-Cyclic Citrullinated Peptide (anti-CCP):
- More specific for RA (90%-95%) but less sensitive than RF.
- Positive results suggest increased risk for radiographic progression.
Serum markers:
- Elevated ESR and CRP, though not sensitive or specific for RA.
- Common occurrence of anemia of chronic disease.
- Normal or increased platelet count, contrasting with low counts in SLE.
- Synovial fluid analysis shows sterility with a high neutrophil count in uncomplicated cases.

Assess disease activity using history, physical examination, and standardized Disease Activity Score.
Treatment based on disease severity:
- Low activity: Initiate DMARD monotherapy.
- High activity: Consider combination DMARD therapy or anti-TNF therapy.
Early initiation of DMARDs is critical to reduce damage and disability.
During pregnancy, prednisone and hydroxychloroquine are recommended anti-inflammatory agents.

Articular Manifestations:
- Symmetric inflammatory polyarthritis involving more than three joints, typically affecting:
  - MCP, PIP, wrist, elbow, knee, ankle, MTP joints.
- Characteristic symptoms include:
  - Morning pain or stiffness lasting more than 60 minutes for at least six weeks.
  - Symptoms improve with movement but worsen with inactivity (Gelling phenomenon).
  - Presence of erythema, warmth, or swelling in joints.
  - Notable hand deformities include ulnar deviation at MCPs, swan neck, and boutonniere deformities.
Spinal Involvement:
- RA may affect the cervical spine, with risk of asymptomatic C1-C2 (atlanto-axial) subluxation.
- Important to perform cervical spine x-ray before tracheal intubation to evaluate for potential complications.