Fibrosing alveolitis responsive to corticosteroids following Legionnaires' disease pneumonia.

Two male patients ages 54 and 58 years had persisting pneumonia with dry cough, dyspnea, weight loss, and fever up to 39 degrees C that did not respond to erythromycin treatment. There was extensive restrictive impairment of ventilation and loss of diffusing capacity for carbon monoxide. Histologic examination of the basal pulmonary infiltrates showed fibrosing alveolitis. Serologic titers indicated that the patients had suffered from Legionella pneumophila infection. We believe that Legionella had caused the fibrosing alveolitis since there was absence of any other causative agents or factors. Both patients responded to corticosteroid treatment with rapid clinical improvement but delayed radiologic regression.