Rheumatoid Arthritis Overview

Rheumatoid Arthritis

• Systemic chronic inflammatory disease affecting diarthrodial joints bilaterally
• Primarily affects the synovium
• Autoimmune disease
• 3:1 female to male ratio
• Characterized by periods of remission and exacerbation
• Possible genetic predisposition and association with Epstein-Barr virus

Pathogenesis

• Genetically susceptible individuals
• Possible involvement of infections, leading to antibody formation
• Antibodies form new antigens
• Production of rheumatoid factor
• Immune complex deposition in the synovium
• Activation of complement cascade
• Inflammation and activation of macrophages
• T cell homing
• Cytokine secretion

Rheumatoid Arthritis - Definition

• Chronic multisystem autoimmune inflammatory disorder
• Primarily affects joints
• Leads to proliferative synovitis
• Can progress to destruction of the articular cartilage and ankylosis

Rheumatoid Arthritis - Etiology

• Genetic Susceptibility:
  • HLA DR4 or DR1 in 65-80% of cases
• Microbial Inciting Agent:
  • Epstein-Barr virus, Borrelia, and Mycoplasma
• Autoimmunity:
  • IgM anti IgG (Rheumatoid Factor)
  • Helper T cell (CD4) against Type II collagen and cartilage glycoprotein-39

Pathology

• Inflammation of the joint and hyperplasia of the synovium
• Synovium infiltrated with lymphocytes and plasma cells
• Fibrin exudation on the synovial fluid, sometimes forming loose bodies

Hyperparathyroidism

• Causes: Parathyroid adenoma, hyperplasia, rare malignancy
• Parathyroid hormone:
  • Promotes phosphate excretion in urine
  • Stimulates osteoclastic activity, resulting in hypercalcemia
  • Stimulates tubular reabsorption of calcium
  • Stimulates intestinal calcium absorption

Hyperparathyroidism Clinical Features

• Stones: kidney stones
• Bones: Brown tumors
• Psychiatric depression
• Gastrointestinal tract irregularities

Secondary Hyperparathyroidism

• Result of renal osteodystrophy and chronic renal failure
• Decreased filtration of phosphate, leading to hyperphosphatemia
• Impact on active Vitamin D
• Decreased calcium absorption in the gastrointestinal tract
• Hypocalcemia, leading to secondary hyperparathyroidism

Osteoarthritis

• Most common joint disease
• Slow progressive degeneration of articular cartilage
• Affects weight-bearing joints and fingers
• Primary: Defect in cartilage, not an inflammatory disease
• Secondary: Trauma, crystal deposits, infection

Causes of Osteoarthritis

• Primary:
  • Defect in cartilage
• Secondary:
  • Intra-articular fracture
  • Previous infective arthritis
  • Rheumatoid arthritis
  • Congenital hip dislocation
• Abnormal Stresses:
  • Paget’s disease with deformity
  • Chronic overuse
  • Metabolic and endocrine factors:
    • Hemochromatosis
    • Gout
    • Calcium phosphate deposition

Secondary Osteoporosis

• Corticosteroids:
  • Inhibition of osteoblastic activity
  • Impaired vitamin D dependent intestinal calcium absorption
  • Secondary hyperparathyroidism
• Hematologic malignancies
• Malabsorption: Gastrointestinal and liver diseases
• Alcoholism:
  • Inhibition of osteoblasts
  • Decreased calcium absorption

Osteomalacia and Rickets

• Inadequate mineralization of newly formed bone matrix (osteomalacia)
• Rickets (children): Open epiphyseal plates and cartilage problems
  • Beaded appearance of costochondral junctions
  • Pectus carinatum
  • Dental abnormalities
• Vitamin D deficiency (dependent)
• Phosphate deficiency (resistant)
• Defects in mineralization process

Osteomalacia and Rickets Clinical Features

• Osteopenia
• Exaggeration of osteoid seams
• Poorly localized pain
• Common sites: Femoral neck, pubic ramus, spine, ribs

Osteoporosis

• Reduced bone mass per unit of bone volume
• Metabolic bone disease
• Normal ratio of mineral to matrix
• Primary: Most common, uncertain etiology
• Secondary: Result of various underlying conditions

Primary Osteoporosis

• Common in postmenopausal women and elderly individuals
• Genetic Factors: Peak bone mass
• Estrogens: Decline in estrogen levels
• Aging: Natural aging process
• Calcium Intake: Recommended 800mg/day
• Exercise: Important for bone health
• Environmental Factors: Smoking decreases estrogen levels

Primary Osteoporosis Clinical Features

• Osteopenia
• Decreased thickness of cortex
• Reduction in the number and size of trabeculae
• Fractures can be the first sign

Osteomyelitis

• Inflammation of bone caused by infection
• Common organisms: Staphylococcus, Streptococcus, Escherichia coli, Neisseria gonorrhea, Haemophilus influenza, Salmonella

Osteomyelitis Routes of Infection

• Direct Penetration:
  • Wounds
  • Fractures
  • Surgery
• Hematogenous:
  • Bloodstream
  • Teeth
  • Metaphyses
  • Knee
  • Ankle
  • Hip

Complications of Osteomyelitis

• Septicemia
• Acute bacterial arthritis
• Pathologic fractures
• Squamous cell carcinoma
• Amyloidosis
• Chronic osteomyelitis

Arthritis

• Inflammation of joints
• Common site for autoimmune injury
• Can affect heart valves and joints

Arthritis Causes

• Infections
• Degeneration: Age, stress, lifestyle
• Exposure of hidden antigens

Arthritis Clinical Features

• Pain: Due to inflammation in the capsule, synovium, and periosteum
• Swelling: Due to inflammation, effusion, and proliferation
• Restricted Movement: Due to pain, fluid, synovial swelling, and damage
• Deformity: Due to misalignment, erosion, and ankylosis

This quiz covers essential information about Rheumatoid Arthritis, including its pathogenesis, definition, and etiology. It addresses the autoimmune nature of the disease and the genetic and environmental factors contributing to its development. Test your knowledge on the characteristics and implications of this chronic inflammatory disorder.