What is Pulmonary Fibrosis?

Pulmonary fibrosis describes a lung condition where the lung tissue becomes scarred, thickened and stiff. There are many kinds of lung scarring with many identified conditions or exposures that can lead to scarring of the lung. These include environmental or occupational exposures such as asbestos, autoimmune diseases such as rheumatoid arthritis, and treatment related exposures such as chemotherapy or radiation.

Idiopathic Pulmonary Fibrosis

There are also a variety of lung scarring diseases that have no known cause. The most common of these is idiopathic pulmonary fibrosis (IPF), a subtype of idiopathic interstitial pneumonia (IIP). The IIPs are categorized by their pathological subtypes and include:

• Usual interstitial pneumonia (UIP)
• Non-specific interstitial pneumonia (NSIP)
• Desquamative interstitial pneumonia (DIP)
• Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD)
• Acute interstitial pneumonia (AIP)
• Cryptogenic organizing pneumonia (COP)
• Lymphocytic interstitial pneumonia (LIP)

How does IPF Differ from Other Forms of Pulmonary Fibrosis?

The pathology associated with IPF is UIP. However, UIP may be associated with other forms of pulmonary fibrosis. In order to diagnose IPF, alternative secondary forms of pulmonary fibrosis such as those induced by autoimmune or connective diseases and environmental or occupational exposures must be excluded.