Autoimmune Diseases Overview

Autoimmune Diseases

• Autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues.
• The immune system, designed to fight off foreign invaders (bacteria, viruses), mistakenly recognizes healthy body parts as foreign.
• This attack involves proteins called autoantibodies, which can damage healthy cells.
• Some autoimmune diseases affect only specific organs, while others, like lupus, affect the whole body.
• Consequences can include tissue destruction, abnormal organ growth, and altered organ function.

Causes of Autoimmune Diseases

• Developing an autoimmune disease is influenced by a complex interplay of factors:
  • Genetic predisposition (DNA).
  • Environmental exposures.
  • Gender (women more likely, especially those of childbearing age).
• Environmental triggers include:
  • Viral/bacterial infections.
  • Sunlight.
  • Chemicals (solvents).
  • Aging.
  • Hormones.
  • Stress.
  • Smoking.
  • Vitamin D deficiency.
  • Diet.

Autoimmunity Classification

• Autoimmune diseases can affect any organ or organ system.
• Approximately 80 autoimmune diseases exist; 14 are prevalent.
• Divided into:
  • Organ-specific: Autoimmunity targets specific organs (e.g., type 1 diabetes).
  • Non-organ-specific (systemic): Autoimmunity targets widespread antigens, affecting multiple organs (e.g., lupus).
  • Overlap exists between categories.

Organ-Specific Autoimmune Diseases (Examples)

• Hashimoto's Thyroiditis:

  • Autoimmune attack on the thyroid gland.
  • Primarily affects women (30-40 years old).
  • Leads to hypothyroidism (underactive thyroid).
  • Can cause a goiter (enlarged thyroid).
  • Diagnosed by blood tests for anti-microsomal and anti-thyroglobulin antibodies.
  • Treatment involves thyroid hormone replacement, iodine, or surgery.

• Goodpasture's Disease:

  • Autoimmune disease affecting the lungs.

Non-Organ Specific (Systemic) Autoimmune Diseases (Examples)

• Systemic Lupus Erythematosus (SLE):

  • Chronic, systemic inflammatory disease.
  • Affects multiple organ systems (joints, skin, kidneys, heart, etc.).
  • Characterized by immune complexes depositing in tissues.
  • Symptoms include joint pain, skin rash (often butterfly-shaped), and renal involvement.
  • Diagnosed using blood tests for antinuclear antibodies (ANAs).
  • Treatment includes pain relief, immunosuppressants, and corticosteroids.

• Rheumatoid Arthritis (RA):

  • Chronic inflammatory disease affecting joints.
  • More common in women.
  • Symptoms include morning stiffness, joint swelling, pain, and stiffness.
  • Diagnosed based on clinical findings, radiographs, and lab tests (rheumatoid factor, ESR, CRP).
  • Treatment utilizes NSAIDs, glucocorticoids, disease-modifying antirheumatic drugs (DMARDs), and biological agents.

Diagnostic Methods (General)

• Blood tests play a crucial role in diagnosing these conditions.
• Specific antibody tests (e.g., anti-microsomal, anti-thyroglobulin, ANA) are used to identify autoantibodies. These may not always be diagnostic but can help pinpoint the disease when considered with clinical symptoms.