Systemic lupus erythematosus

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a long-term autoimmune disorder that may affect the skin, joints, kidneys, brain, and other organs.

Causes

The cause is unknown. Research involves:

• The role of viruses
• Hormonal factors (the female predominance and peak incidence in women of childbearing age is circumstantial evidence for hormonal factors in the pathogenesis of SLE)
• Genetic abnormalities (they may create a tendency for autoimmune responses, which are then triggered by additional factors, such as viruses or sunlight)
• Environmental factors (virus, sunlight)
• Immune complex formation - many of the clinical manifestations are due to the effects of circulating immune complexes on various tissues or to the direct effects of antibodies to cell-surface components

Signs and symptoms

Patients may present with any of the following manifestations^[4] :

• Constitutional (e.g. fatigue, fever, arthralgia, weight changes)
• Musculoskeletal (e.g. arthralgia, arthropathy, myalgia, frank arthritis, a vascular necrosis)
• Dermatologic (e.g. malar rash, photosensitivity, discoid lupus)
• Renal (e.g. acute or chronic renal failure, acute nephritic disease)
• Neuropsychiatry (e.g. seizure, psychosis)
• Pulmonary (e.g. pleurisy, pleural effusion, pneumonitis, pulmonary hypertension, interstitial lung disease)
• Gastrointestinal (e.g. nausea, dyspepsia, abdominal pain)
• Cardiac (e.g. pericarditis, myocarditis)
• Hematological (e.g. cytopenias such as leucopenia, lymphopenia, anemia, or thrombocytopenia)

In patients with suggestive clinical findings, a family history of autoimmune disease should raise further suspicion of SLE.

The following are useful standard laboratory studies when SLE is suspected:

• CBC with differential
• Serum creatinine
• Urinalysis with microscopy

Other laboratory tests that may be used in the diagnosis of SLE are as follows:

• ESR or CRP results
• Complement levels
• Liver function tests
• Creatine kinase assay
• Spot protein/spot creatinine ratio
• Autoantibody tests

The following imaging studies may be used to evaluate patients with suspected SLE:

• Joint radiography
• Chest radiography and chest CT scanning
• Echocardiography
• Brain MRI/ MRA

Procedures that may be performed in patients with suspected SLE include the following:

• Arthrocentesis
• Lumbar puncture
• Renal biopsy

Treatment

Management of SLE often depends on the individual patient’s disease severity and disease manifestations although hydroxychloroquine has a central role for long-term treatment in all SLE patients.

Medications used to treat SLE manifestations include the following:

• Biologic DMARDs (disease-modifying ant rheumatic drugs): Belimumab, rituximab, IV immune globulin
• No biologic DMARDS: Cyclophosphamide, methotrexate, azathioprine, mycophenolate, cyclosporine
• No steroidal anti-inflammatory drugs (NSAIDS; e.g. ibuprofen, naproxen, diclofenac)
• Corticosteroids (e.g. methylprednisolone, prednisone)
• Antimalarials (e.g. hydroxychloroquine)