Systemic Lupus Erythematosus

A chronic inflammatory connective tissue disorder that occurs mainly in women of childbearing age but also in older persons.

The incidence of systemic lupus erythematosus (SLE) declines in old age. The prevalence is 12% for patients > 50. Furthermore, the female:male ratio declines from 9:1 in younger persons to about 3:1 in elderly persons. Unlike for idiopathic SLE, the incidence and prevalence for drug-induced SLE increases with age, probably because the elderly use many of the causative drugs. Procainamide, hydralazine, chlorpromazine, methyldopa, penicillamine, quinidine, sulfasalazine, and isoniazid are known causes. Captopril, lithium, anticonvulsants, -blockers, propylthiouracil, levodopa, and nifedipine are strongly suspected.

The cause of idiopathic SLE is unknown. The pathogenesis involves the formation of autoantibodies and immune complexes, which damage several organs, especially the kidneys.

Symptoms, Signs, and Diagnosis

The classic malar rash occurs in only about 20% of elderly patients, but other diagnostic symptoms and signs are similar in elderly and younger patients. Arthralgia is prominent, and serositis is common. Dermatitis, asymmetric migratory arthritis, photosensitivity, pleurisy, pericarditis, pneumonitis, and Sjögren's syndrome are typical in idiopathic and drug-induced SLE, but central nervous system and renal manifestations are uncommon in drug-induced SLE. Symptoms of drug-induced SLE can occur up to 2 years after the drug is discontinued.

Some authorities contend that central nervous system, renal, and hematologic manifestations are unusual in elderly patients with SLE. Hypercoagulability may occur due to the presence of the lupus anticoagulant.

Laboratory results for antinuclear antibodies (ANA) are positive in 95% of patients with idiopathic SLE and in 100% with drug-induced SLE. About 50% of patients taking procainamide have positive ANA test results, but only about 5 to 10% develop an SLE-like syndrome. The presence of anti-double-stranded DNA antibodies is considered diagnostic of SLE. Many other autoantibodies are present in patients with SLE but are not usually helpful in diagnosis. Serum complement levels may be depressed, particularly in patients with renal disease. Urinalysis may show proteinuria or cells and casts on microscopic examination; the CBC count may show thrombocytopenia, leukopenia, or anemia. The prothrombin time may be prolonged if the lupus anticoagulant is present.

Treatment

Patients with mild disease, who have primarily arthritis or dermatitis, may respond to NSAIDs. NSAIDs must be used with caution in the elderly, who have an increased risk of renal toxicity. COX-2 inhibitors are likely to cause less gastrointestinal toxicity and platelet dysfunction. However, one of the COX-2 inhibitors, rofecoxib (withdrawn from market) appears to increase the risk of cardiovascular events after long-term use. The risk of cardiovascular events with other COX-2 inhibitors is undergoing evaluation. Hydroxychloroquine may be useful, particularly for patients with dermatitis. Although rare, ocular toxicity may occur with this drug, and an initial eye examination is recommended. High-dose corticosteroids are indicated for patients with central nervous system, renal, or severe hematologic manifestations or for those with fever, weight loss, or severe pleurisy or pericarditis. In the elderly, corticosteroid use increases the risk of osteoporosis and subsequent fracture; measurements of bone mineral density may help assess risk.

For drug-induced SLE, discontinuing the causative drug and administering an NSAID may be sufficient. However, some patients, particularly those with severe pericarditis, may need prednisone 40 to 60 mg/day po for several weeks.