Systemic Lupus Erythematosus

Description

• Chronic autoimmune disease; peak onset between ages 15 and 40 yr; characterized by flares and remissions
• Multisystem disease with diverse clinical manifestations:
  • Mucocutaneous:
    • Most commonly involved system
    • 4 specific skin rashes
  • Arthritis
  • Cardiac:
    • Endocarditis
    • Myocarditis
    • CHF
    • Conduction abnormalities
    • Atherosclerosis
    • MI
  • Renal:
    • Glomerulonephritis
    • Renal failure
  • Pulmonary:
    • Pleural effusion (usually exudative)
    • Pneumonitis/pleuritis
    • Pulmonary hemorrhage
    • Pulmonary embolism
    • Pneumonia
    • Pulmonary edema
    • Pulmonary hypertension
  • Neurologic:
    • Lupus cerebritis
  • Vascular:
    • Vasculitis
    • Thrombosis
    • Atherosclerosis
  • GI:
    • Peritonitis
    • Mesenteric vasculitis and ischemia
    • Pancreatitis

• Neonatal lupus may occur when maternal autoantibodies cross the placenta:
  • Associated with transient anemia and thrombocytopenia
• Congenital heart block is the most serious complication

• 10 times greater risk of MI due to atherosclerosis
• High incidence of osteoporosis related to chronic steroid use

Risk Factors

• More common in females than males (9:1 ratio)
• More common in women of childbearing age
• More common in African Americans
• Higher frequency of systemic lupus erythematosus (SLE) and other autoimmune diseases among first-degree relatives

Etiology

• Autoantibody production against cell nucleus and cytoplasmic structures, leading to inflammatory changes, vasculitis, and immune complex deposition in multiple organ systems
• A significant percentage of patients have an associated antiphospholipid syndrome:
  • Characterized by antibodies against cellular phospholipid components
  • Tendency toward recurrent vascular thrombosis
• Lupus is a chronic disease with several exacerbating factors:
  • Infection
  • Sun exposure
  • Fatigue
  • Trauma
  • Medications (sulfonamides)
  • Stress
  • Diet
• Drug-induced lupus is a milder disease that eventually resolves once the drug is discontinued. Usually presents with skin and joint manifestations while renal and neurologic involvement is rare
• Common medications that induce lupus include:
  • Chlorpromazine, methyldopa, procainamide, hydralazine, isoniazid, quinidine, minocycline