Clearly, progress is needed to improve understanding of ILD etiology, pathogenesis, diagnosis and treatment. Etiology and Pathogenesis Return to the Table of Contents. In a minority of cases, ILD evolves from a known insult to the interstitium. Drug-induced lung injury also contributes a fair number of cases. Among other known causes of ILD, hypersensitivity pneumonitis, an immunologic response to organic dusts such as molds and bird antigens, is relatively common.
Aspiration syndromes represent another common source of chronic lung disease in children.
The classic histologic patterns of idiopathic ILD are seen less often in children. Other frequently suspected sources of ILD in children include exposure to environmental contaminants, infectious agents and autoimmune reactions and disorders. However, in an appreciable number of cases, epidemiologic data are insuficient to clearly implicate these factors. Idiopathic pulmonary fibrosis, which is more common in adults than in children, is characterized by a constellation of clinical, radiographic and pathologic abnormalities in the absence of an identifiable cause. Despite the diversity of diseases that constitute ILD of known cause, the majority of patients have idiopathic disease.