Polyarthritis

Osteoarthritis vs Rheumatoid Arthritis (Top HY)

• Overview of RA

🔸 Pain in weight-bearing joints after use (e.g., at the end of the day).
🔸 Can have morning stiffness but less than 30 min.
🔸 Improves with rest.
🔸 Asymmetric joint involvement.

🔹Systemic symptoms 🔸 Absent 🔹 Knee cartilage loss begins medially (“bowlegged”). | 🔹 Joint Pain 🔸 Morning stiffness lasting > 1 hour. 🔸 Pain improves with use. 🔸 Symmetric joint involvement. 🔹 Systemic symptoms 🔸 Present→ fever, fatigue, weight loss. 🔹 Extraarticular manifestations common. | | Joint Findings | 🔹 Bone 🔸 Osteophytes (bone spurs). 🔸 Loose bodies. 🔸 Subchondral sclerosis and cysts. 🔹 Joint space 🔸 Joint space narrowing (asymmetric). 🔹 Hand 🔸 Heberden nodes (at DIP) 🔸 Bouchard nodes (at PIP) 🔸 And 1st CMC; not MCP 🔹 Extra 🔸 Synovial fluid noninflammatory (WBC < 2000/mm³) | 🔹 Bone 🔸 Erosions. 🔸 Juxta-articular osteopenia. 🔸 Subchondral cysts. 🔹 Joint space 🔸 Joint space narrowing (symmetric). 🔹 Hand 🔸 Ulnar finger deviation 🔸 Swan neck 🔸 Boutonniere. 🔸 Involves MCP, PIP not DIP or 1st CMC. 🔹 Extra 🔸 Cervical subluxation 🔸 Soft tissue swelling | | Treatment | 🔹 Activity modification. 🔹 Acetaminophen. 🔹 NSAIDs. 🔹 Intra-articular glucocorticoids. | 🔹 NSAIDs. 🔹 Glucocorticoids. 🔹 Disease-modifying agents (e.g., methotrexate, sulfasalazine). 🔹 Biologic agents (e.g., TNF-α inhibitors).

→ DMAs takes time to show relief unlike glucocorticoids (rapid acting). |

<aside> 💡 Extraarticular Manifestations of Rheumatoid Arthritis

• Rheumatoid Nodules
  • Fibrinoid necrosis with palisading histiocytes
  • Located in subcutaneous tissue and lung
  • If associated with pneumoconiosis→ Caplan syndrome
• Skeletal
  • Cervical Subluxation
    • Affect mainly atlantoaxial joint
    • Extension of the neck during endotracheal intubation can worsen the subluxation, leading to acute compression of the spinal cord and/or vertebral arteries → flaccid paralysis with decreased or absent reflexes below the level of the compression
  • Carpal Tunnel Syndrome
• Respiratory→ Interstitial Lung Disease, Pleuritis
• Immunologic→ Sjögren Syndrome, Scleritis
• Others→ Pericarditis, Anemia of Chronic Disease, AA Amyloidosis
• Neutropenia + Splenomegaly (Felty Syndrome)
  • SANTA→ (Splenomegaly, Anemia, Neutropenia, Thrombocytopenia, Arthritis (Rheumatoid) </aside>

<aside> 🧠

Pathogenesis of RA

• Activation of T lymphocytes in response to rheumatoid antigens (eg, citrullinated peptides)→ Release cytokines (eg, IL-1, TNF-α) that cause synovial hyperplasia and cartilage destruction → The accelerated metabolic rate of the inflamed synovial tissue leads to local hypoxia → resulting in synovial angiogenesis (neovascularization).
• New blood vessels provide nutrients that facilitate expansion of inflamed synovium into a rheumatoid pannus (invasive mass composed of fibroblast-like synovial cells, granulation tissue, and inflammatory cells)→ which can destroy the articular cartilage and underlying subchondral bone.
• Ossification of the pannus can lead to fusion of the bones across the affected joint (bony ankylosis) </aside>

• Other picture

     **Pathophysiology of osteoarthritis**

• Overlay

Pathophysiology of rheumatoid arthritis

• Overlay

Affected hand joints in RA vs OA

       Heberden nodes

       Bouchard nodes

Hand deformities of RA

Rheumatoid nodules with ulnar deviation

• Other pictures of hand deformities

Seronegative Spondyloarthritis

Overview

• Arthritis without rheumatoid factor (no anti-IgG antibody).
• Strong association with HLA-B27 (MHC class I serotype).

Common symptoms

• Inflammatory back pain→ morning stiffness, improves with exercise
• Peripheral arthritis
• Enthesitis
  • Inflammation at sites of insertion of tendons, ligaments , joint capsules
  • Common presentations
    • Achilles tendinitis → posterior heel pain
    • Plantar fasciitis → Plantar heel pain
    • Dactylitis → sausage digits
• Dactylitis→ "sausage fingers"
• Uveitis

Subtypes (PAIR)

• Psoriatic arthritis
• Ankylosing spondylitis
• Inflammatory bowel disease
• Reactive arthritis

Left index finger dactylitis

Psoriatic Arthritis

• Facts Sheet

• Prevalence

  • Seen in fewer than 1/3 of patients with psoriasis.

• Association

  • Skin psoriasis and nail lesions.

• Joints Involvement

  • Asymmetric and patchy involvement.

• Characteristic Features

  • Dactylitis ("sausage fingers")
  • X-ray→ "Pencil-in-cup" deformity of DIP joints.

Pencil in cup deformity in DIP

Ankylosing Spondylitis

• Prevalence

  • More common in males
  • Age of onset usually 20–40 years.

• Pathogenesis

  • Altered gut biome/defects in mucosal barrier→ Increased production of IL-17, TNF-a & prostaglandins→ induce activation of osteoclast precursor cells and bony erosions→ Once inflammation subsides, the reparative process leads to excessive new bone formation typically occurs at the junction of the periosteal margin and adjacent cartilage, leading to bridging syndesmophytes in the vertebral column.

• Joints Involvement

  • Symmetric involvement of spine and sacroiliac joints.

• Characteristic Features

  • Ankylosis (joint fusion)
  • Tenderness at spine, sacroiliac joints
  • Postyral alteration
  • Uveitis
  • Aortic regurgitation

• Confirmatory test

<aside> 💡

</aside>

<aside> 🧩

</aside>