Pulmonary Fibrosis

Pulmonary fibrosis is a broad family of more than 200 interstitial lung diseases in which the lung parenchyma becomes scarred. As normal alveolar architecture is replaced by stiff fibrotic tissue, the lungs lose compliance: the patient must work harder to expand them, but each breath produces less useful ventilation. Thickened or destroyed alveolar-capillary surfaces also impair oxygen transfer, especially during exertion when oxygen demand rises and capillary transit time falls. The scarring is generally irreversible. “Pulmonary fibrosis” is not synonymous with idiopathic pulmonary fibrosis (IPF); fibrosis may result from autoimmune disease, occupational or environmental exposure, medication, radiation, or another identifiable cause. Establishing the cause matters because treatment and prognosis differ.