[Pulmonary arterial hypertension and systemic lupus erythematosus. Apropos of 2 cases. Review of the literature].
Pulmonary arterial hypertension may develop in patients with systemic lupus erythematosus (SLE) in the absence of lung tissue lesion or embolism in the pulmonary circulation. Its mechanisms and prognosis are imperfectly known, although various suggestions have been made concerning the possible role of pulmonary arterial spasm, immune complex arteritis or arterial wall fibrosis. We report two cases of SLE in female patients who presented with clinical signs of pulmonary arterial hypertension. The fact that pulmonary arterial hypertension regressed completely in one patient and resulted in death in the other points to different pathogenic mechanisms. In the first patient the dramatic therapeutic effectiveness of a calcium inhibitor suggests that an arterial spasm was involved, whereas the anatomical lesions found in the second patient are in favour of a fibrotic inflammatory arteritis. This pathogenic heterogeneity of pulmonary arterial hypertension in SLE, which may correspond to different evolutive stages of the disease, is documented by a review of the literature with special attention to the frequency and to the clinical biochemical, haemodynamic and histological aspects of this complication of SLE.