Pulmonary hemosiderosis is a rare condition characterized by an abnormal accumulation of hemosiderin in the lungs. Deposition of hemosiderin results from bleeding into the lungs with diffuse alveolar hemorrhage, rather than from hemorrhage from larger arteries. In chronic pulmonary hemosiderosis, bleeding usually is low-grade, repetitive, or persistent, often with superimposed episodes of brisk hemorrhage. Pulmonary hemosiderosis is classified as isolated, associated with other organ dysfunction, or secondary, depending on the pathogenesis (Box 237.1).

Idiopathic pulmonary hemosiderosis occurs at any age, but it usually is seen in childhood. Familial occurrence has been reported. No gender difference in incidence exists. Most cases in infancy and childhood are isolated and idiopathic, with no identifiable etiology. Often, the idiopathic form is more episodic and may be exacerbated by viral illness. Pulmonary hemosiderosis resulting from hypersensitivity to cow’s milk has been described in young infants, but this relationship is questionable. Associated gastrointestinal or upper respiratory symptoms may occur. A few cases of pulmonary capillary
hemangiomatosis have been reported in children and young adults. This condition is characterized by a proliferation of capillaries that can result in significant alveolar hemorrhage, hemosiderosis, and pulmonary hypertension. Pulmonary capillaritis, a small vessel vasculitis has been reported to cause diffuse alveolar hemorrhage in children.

Usually, Goodpasture syndrome occurs in young men, and development of pulmonary hemosiderosis may precede renal involvement. Diffuse pulmonary hemorrhage with other forms of nephritis is an unusual occurrence in children. Acute pulmonary hemorrhage and hemosiderosis are rare features of numerous collagen-vascular diseases, such as systemic lupus erythematosus in children, but they may precede other systemic manifestations. Systemic vasculitis, such as that seen in Wegener granulomatosis and Henoch-Schönlein purpura, may cause diffuse pulmonary hemorrhage. Selected drug and chemical exposures have been associated with diffuse pulmonary hemorrhage. Reports of case clusters have suggested an association with exposure to environmental factors such as contaminants from water damage or environmental tobacco smoke. A series of infant cases in Cleveland, Ohio suggested an association with exposure to the toxigenic fungus Stachybotrys atra (Stachybotrys chartarum) in infants’ homes. Further epidemiologic review has raised doubt regarding the possible relation to mold exposure in these cases. One case of a child with pulmonary hemorrhage with a positive bronchoalveolar lavage culture for Stachybotrys and home exposure has been reported. Analysis of this isolate and isolates from Cleveland case and control homes suggest that some Stachybotrys strains are more pathogenic, by producing siderosphores and hemolysin.

Pulmonary hemosiderosis may mimic other chronic pulmonary conditions of childhood, including asthma, cystic fibrosis, and alveolar filling diseases. Acute bleeding episodes may be confused with bacterial pneumonia. Hemoptysis may be seen in bronchiectasis and tuberculosis.