Respiratory manifestations of systemic lupus erythematosus: old and new concepts.

The respiratory system is commonly involved in systemic lupus erythematosus. Lung disorders are classified as primary (due to lupus) and secondary to other conditions. Pleuritis and pulmonary infections are the most prevalent respiratory manifestations of each type. Other infrequent manifestations include interstitial lung disease, acute lupus pneumonitis, diffuse alveolar haemorrhage, pulmonary arterial hypertension, acute reversible hypoxaemia and shrinking lung syndrome. Even when current diagnostic tests contribute to an earlier diagnosis, the treatment of these manifestations is based on clinical experience and small series. Larger controlled trials of the different therapies in the treatment of those lung manifestations of lupus are needed. Overall malignancy is little increased in lupus, but lung cancer and non-Hodgkin's lymphoma are among the most frequent types of cancer found in these patients. As survival in lupus patients has improved over recent decades, avoiding pulmonary damage emerges as an important objective.