rheumatoid arthritus:

Rheumatoid Arthritis (RA) – Characteristics & Radiological Features

1. Cellular Level (Microscopic Changes)

• Autoimmune Attack: T-cells, B-cells, and macrophages attack synovium.

• Cytokine Storm: IL-1, IL-6, and TNF-α promote inflammation.

• Pannus Formation: Thickened, hyperplastic synovium invades cartilage and bone.

• Osteoclast Activation: Leads to bone erosion.

• Angiogenesis: Increased blood vessel formation in the synovium.

2. Tissue Level (Histopathology)

• Synovial Hypertrophy: Overgrowth of synovial lining (pannus formation).

• Inflammatory Cell Infiltration: Lymphocytes, plasma cells, macrophages.

• Cartilage Destruction: Due to pannus invasion.

• Bone Erosion: Due to osteoclast activity.

• Fibrosis & Joint Deformity: Chronic inflammation leads to permanent damage.

3. Organ Level (Joint Changes)

• Symmetrical Polyarthritis: Affects small joints of hands, wrists, feet first.

• Morning Stiffness >1 Hour: Improves with movement.

• Swollen, Warm, Tender Joints: Due to inflammation.

• Joint Deformities: Swan-neck, boutonnière deformity, ulnar deviation.

4. Whole-Person Level (Clinical Features)

• Systemic Disease: Fatigue, weight loss, low-grade fever.

• Extra-Articular Manifestations:

  • Skin: Rheumatoid nodules.

  • Lungs: Interstitial lung disease.

  • Heart: Pericarditis, increased cardiovascular risk.

  • Eyes: Scleritis, keratoconjunctivitis sicca.

• Risk Factors: Female gender, smoking, HLA-DR4, family history.

Radiological Features of Rheumatoid Arthritis (X-ray)

🔑 Mnemonic: LESS

1. L - Loss of Joint Space (due to cartilage destruction)

2. E - Erosions (marginal, near joint edges)

3. S - Soft Tissue Swelling (synovial hypertrophy)

4. S - Subluxation & Deformity (late-stage joint instability)

Additional Imaging Features:

• MRI: Early bone marrow edema, synovitis, erosions.

• Ultrasound: Detects active synovitis and erosions.

Quick Memorization Tips

1. "Autoimmune Attack Destroys Joints" → Chronic inflammation leads to destruction.

2. "LESS Mnemonic" → Loss of space, Erosions, Soft tissue swelling, Subluxation.

3. "RA = Red Angry joints" → Symmetric inflammation with morning stiffness.