Systemic Lupus Erythematosus

Key Features

Essentials of Diagnosis

• Occurs mainly in young women

• Rash over areas exposed to sunlight

• Joint symptoms in 90% of patients

• Anemia, leukopenia, thrombocytopenia

• Glomerulonephritis, central nervous system disease, and complications of antiphospholipid antibodies are major sources of disease morbidity

• Serologic findings: antinuclear antibodies (100%), anti–double-stranded DNA antibodies (approximately two-thirds), and low serum complement levels (particularly during disease flares)

General Considerations

• An inflammatory autoimmune disorder

• Characterized by autoantibodies to nuclear antigens

• Can affect multiple organ systems

• Many of its clinical manifestations are secondary to the trapping of antigen-antibody complexes in capillaries of visceral structures or to autoantibody-mediated destruction of host cells (eg, thrombocytopenia)

• The clinical course is marked by spontaneous remission and relapses

• Severity may vary from a mild episodic disorder to a rapidly fulminant, life-threatening illness

Demographics

• About 85% of patients are women

• Sex hormones play a role; most cases develop after menarche and before menopause

• Among older individuals, the sex distribution is more equal

• Race is also a factor, as SLE occurs in 1:1000 white women but in 1:250 black women

• Familial occurrence of SLE has been repeatedly documented

Clinical Findings

Symptoms and Signs

• The systemic features include fever, anorexia, malaise, and weight loss

• Most patients have skin lesions at some time

  • The characteristic "butterfly" (malar) rash affects less than half of patients

  • Other cutaneous manifestations are

    • Panniculitis (lupus profundus)

    • Discoid lupus

    • Typical fingertip lesions

    • Periungual erythema

    • Nail fold infarcts

    • Splinter hemorrhages

• Alopecia is common

• Mucous membrane lesions tend to occur during periods of exacerbation

• Raynaud phenomenon, present in about 20% of patients, often antedates other features of the disease

• Joint symptoms, with or without active synovitis

  • Occur in over 90% of patients

  • Often the earliest manifestation

  • The arthritis can lead to reversible swan-neck deformities, but erosive changes are almost never noted on radiographs

  • Subcutaneous nodules are rare

• Ocular manifestations include

  • Keratoconjunctivitis sicca

  • Retinal vasculopathy, for example

    • Cotton-wool spots

    • Episcleritis

    • Scleritis

    • Optic neuropathy

• Pulmonary manifestations

  • Pleurisy and pleural effusion (common)

  • Pneumonitis, interstitial lung disease, and pulmonary hypertension (rare)

  • Alveolar hemorrhage (uncommon but life-threatening)

• Cardiac manifestations

  • The pericardium is affected in the majority of patients

  • Heart failure may result from myocarditis and hypertension

  • Cardiac arrhythmias are common

  • Atypical verrucous endocarditis of Libman-Sacks is usually clinically silent but occasionally can produce acute or chronic valvular regurgitation—most commonly mitral regurgitation

• Mesenteric vasculitis

  • May closely resemble polyarteritis nodosa, including the presence of aneurysms in medium-sized blood vessels

  • Abdominal pain (particularly postprandial), ileus, peritonitis, and perforation may result

• Several forms of glomerulonephritis may occur, including mesangial, focal proliferative, diffuse proliferative, and membranous; some patients may also have interstitial nephritis

• Hematologic manifestations include

  • Leukopenia

  • Autoimmune hemolytic anemia

  • Immune thrombocytopenia

  • Thrombotic thrombocytopenic purpura

Differential Diagnosis