Inflammatory pulmonary nodules in Kawasaki disease

Symptomatic pulmonary manifestations of Kawasaki disease (KD) are uncommon. However, epidemiologic, radiologic, and histologic studies have indicated that respiratory symptoms and findings occur in KD and suggest that the KD agent may have a respiratory portal of entry. We report on three young infants with KD who developed pulmonary nodules, in addition to coronary artery aneurysms. Two patients had pathologic specimens available, one from biopsy and the other from autopsy. The nodules had predominantly mononuclear cell infiltrates, which were within the lung parenchyma and infiltrating vessel walls. Immunohistochemical studies of the nodules, using antibodies to common leukocyte antigen (LCA) and factor VIII-related antigen, confirmed the inflammatory nature of the lesions and showed capillary proliferation. IgA plasma-cell infiltration was observed in the nodule, consistent with previous KD findings of IgA plasma-cell infiltration in the vessel walls, kidneys, pancreas, and upper respiratory tract. The two patients with nonfatal KD were treated with intravenous immunoglobulin and aspirin, with resolution of the nodules. We propose that when pulmonary involvement occurs in KD, it ranges from subclinical interstitial micronodular infiltrates to larger inflammatory pulmonary nodules. These pulmonary infiltrates and nodules likely reflect the host response to the etiologic agent of KD, and may resolve with the disease process. Recognition of this pulmonary complication of KD may enable cautious observation of such lesions for spontaneous resolution.