Acute pulmonary edema, capillaritis and alveolar hemorrhage: pulmonary manifestations coexistent in antiphospholipid syndrome and systemic lupus erythematosus?

Pulmonary capillaritis and alveolar hemorrhage are rare yet serious and life threatening complications of systemic lupus erythematosus (SLE). Pulmonary manifestations of antiphospholipid syndrome (APS) are similar and include, apart from pulmonary embolism and pulmonary hypertension, pulmonary capillaritis, diffuse alveolar hemorrhage and respiratory insufficiency in patients with catastrophic APS. Herein, we described the radiological features of three patients with pulmonary and SLE-associated APS, manifested with pulmonary edema, capillaritis and alveolar hemorrhage. We observed that the radiological features of pulmonary APS shared close resemblance to those of pulmonary SLE. Based on these findings, we conclude that both entities are not only histologically, but also radiologically indistinguishable from each other, suggesting a mutual pathogenetic mechanism. This raises the question of whether some of the reported lupus pneumonitis cases in the past might be manifestations of APS rather than of SLE.