Definition
Idiopathic pulmonary fibrosis is a pulmonary disease characterized by interstitial fibrosis of unknown etiology.

Pathology

• The pathology, which is non-specific, varies with the stage of the disease.
• The dominant pattern is inflammatory early on leading to organization of the exudate and interstitial fibrosis in the later stage.
• The severe septal thickening (fibrosis) leads to a "honeycomb" appearance of the lung and pronounced alveolocapillary block. Refer to Figure 15-35 in your textbook.

Etiology/Pathogenesis
Unknown. In actually this pathologic condition may be the end stage of manydifferent pulmonary diseases.

Pathophysiology
Hypoxemia, dyspnea, cyanosis, pulmonary hypertension and cor pulmonale.