Autoimmune Diseases Overview

Autoimmune Diseases

• Autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues, mistaking them for foreign invaders.
• Immune system normally fights off germs like bacteria and viruses.
• Autoimmune diseases involve proteins called autoantibodies attacking healthy cells.
• Some autoimmune diseases target specific organs, while others affect the entire body.

Types of Autoimmune Diseases

• Organ-Specific: Autoimmunity targets a specific organ component, e.g., Type 1 diabetes damages the pancreas.
  • Examples include: Hashimoto's thyroiditis, Goodpasture's disease.
• Non-Organ Specific (Systemic): Autoimmunity targets antigens present in multiple organs.
  • Examples include: Systemic lupus erythematosus (SLE), rheumatoid arthritis.
• Overlap: Some diseases exhibit features of both organ-specific and non-organ-specific disease.

Causes of Autoimmune Diseases

• Autoimmune diseases result from a complex interplay of factors:
  • Genetics (DNA)
  • Environmental factors (e.g., infections, sunlight, chemicals)
  • Gender (women are more susceptible, particularly at childbearing age)

Additional Factors Triggering Autoimmunity

• Viral and bacterial infections
• Sunlight exposure
• Chemical exposure (solvents)
• Aging
• Hormonal changes
• Stress
• Smoking
• Vitamin D deficiency
• Diet

Hashimoto's Thyroiditis

• Autoimmune disorder affecting the thyroid gland.
• Characterized by the immune system attacking and destroying thyroid cells.
• Results in hypothyroidism (underactive thyroid).
• Most common in women aged 30-40.
• Symptoms often include goiter (enlarged thyroid), fatigue, muscle weakness, and weight gain.
• Diagnosis involves blood tests for thyroid function and specific autoantibodies (anti-microsomal and anti-thyroglobulin, with anti-microsomal being more sensitive).
• Treatment usually involves thyroid hormone replacement therapy. Other treatment options like radioactive iodine or surgery may be necessary.

Type 1 Diabetes Mellitus (T1DM)

• Immune system destroys insulin-producing cells in the pancreas, leading to impaired sugar uptake by cells.
• Elevated blood sugar damages blood vessels and various organs (heart, kidneys, eyes, nerves).

Systemic Lupus Erythematosus (SLE)

• Chronic, systemic inflammatory disease caused by immune complex formation.
• Affects many body parts including joints, skin, kidneys, heart, lungs, blood vessels, and brain.
• Peak onset between ages 20 and 40.
• More prevalent in women.
• Symptoms are highly variable and non-specific, e.g., joint pain (polyarthralgia and arthritis), skin rash (often butterfly-shaped), kidney involvement.
• Kidney involvement (most common cause of death in SLE) results from immune complexes depositing in kidney tissue.
• Diagnosis involves blood tests for antinuclear antibodies (ANA).
• Treatment involves various medications depending on the affected systems.

Rheumatoid Arthritis (RA)

• Chronic inflammatory disease primarily affecting joints. Women are three times more likely to be affected than men.
• Typical onset between ages 20 and 40, but can appear at any age.
• Characterized by joint pain, inflammation, and stiffness (especially in the morning).
• Other signs include: joint swelling, swollen hand/wrist joints, symmetrical arthritis, subcutaneous nodules, positive rheumatoid factor test, and X-ray evidence of joint erosion.
• Diagnosis involves clinical examination, imaging, and blood tests for rheumatoid factor (RF) and inflammatory markers.
• Treatment options include NSAIDs, corticosteroids, disease-modifying antirheumatic drugs (DMARDs), and biological agents/therapies.