PULMONARY MANIFESTATIONS.

Pulmonary involvement occurs in most patients and is manifested as pleurisy, coughing, dyspnea, abnormal pulmonary function tests, or chest radiographic abnormalities. Pleurisy occurs in over 50% of patients; the most common cause is chest wall pain on local pressure and/or movement. Pleuritis (inflammation of the pleura) also causes pleurisy. It is diagnosed by the presence of a pleural friction rub and/or the radiographic presence of a pleural effusion. Effusions typically have low complement and protein levels, few WBCs (the pleura has mononuclear cells), glucose levels approximating plasma levels (by contrast, they are low in rheumatoid arthritis), and LE cells. Cough usually represents an infection, but pulmonary edema secondary to cardiac or renal failure or fluid overload in a patient receiving corticosteroids should be considered.

Acute lupus pneumonitis occurs in 5 to 12% and is characterized by fever, cough (even hemoptysis), pleurisy, and dyspnea. Radiography shows diffuse acinar infiltrates, especially in the lower lobes. Subsequently, interstitial infiltrates and fibrosis may develop, with pulmonary function abnormalities. The prognosis is poor.

Pulmonary hypertension may complicate SLE but is more frequent with scleroderma or mixed connective tissue disease. Raynaud's phenomenon is common. Late findings include dyspnea, hypoxemia, restricting lung disease, and reduced CO₂diffusing capacity.

The shrinking or vanishing lung syndrome has been described in some patients. It is believed to result from weakening and elevation of the diaphragm (lung fields are radiographically clear).

CARDIOVASCULAR MANIFESTATIONS.

Pericardial effusion is observed by echocardiography in most patients, and clinical pericarditis, manifested as substernal chest pain, a pericardial rub, and electrocardiographic (ECG) changes, has been noted in up to 48% of patients. Tamponade and restrictive pericarditis are rare. The fluid has characteristics similar to SLE pleural fluids.

Myocarditis, characterized by resting tachycardia, arrhythmias, ECG non-specific ST-T wave abnormalities, and unexplained cardiomegaly with congestive heart failure, has been noted in 8 to 78% of large series.

Coronary artery disease is being recognized increasingly, particularly in patients with long-standing disease, especially those receiving chronic corticosteroids. As a result, a greater number of younger patients with angina, myocardial infarctions, and congestive heart failure are being seen. The cause of the premature atherosclerosis remains unclear, but steroid-induced lipid abnormalities, immune complex deposition along blood vessels, and hypertension may all play a role. Hypertension is common, especially with flares of nephritis, chronic renal disease, and steroid use.

Valvular disease has been noted in up to 25% of patients; most common is mitral valve prolapse. Murmurs are even more common and may represent valvular disease or be due to anemia, fever, and/or cardiomegaly. Echocardiography is very useful to detect Libman-Sacks verrucous endocarditis. Verrucae are typically near the edge of the valve. Bacterial endocarditis may develop on damaged valves.

Thrombophlebitis occurs in more than 10% of patients with SLE. It most commonly affects the lower part of the leg and is often associated with antiphospholipid antibodies and oral contraceptives. The renal veins and inferior vena cava are rarely involved, but their involvement may cause nephrotic syndrome; pulmonary embolisms are uncommon.

HEMATOLOGIC CONSIDERATIONS.

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