Interstitial Lung Disease

Interstitial Lung Disease (ILD): Overview

Interstitial lung disease (ILD) is a broad category of lung diseases that includes more than 130 disorders which are characterized by scarring (i.e. “fibrosis”) and/or inflammation of the lungs. ILD accounts for 15 percent of the cases seen by pulmonologists (lung specialists).

In ILD, the tissue in the lungs becomes inflamed and/or scarred. The interstitium of the lung refers to the area in and around the small blood vessels and alveoli (air sacs). This is where the exchange of oxygen and carbon dioxide take place. Inflammation and scarring of the interstitium disrupts this tissue. This leads to a decrease in the ability of the lungs to extract oxygen from the air.

There are different types of interstitial lung disease that fall under the category of ILD. Some of the common ones are:

  • Idiopathic (unknown) pulmonary fibrosis (IPF)
  • Connective tissue or autoimmune disease-related ILD
  • Hypersensitivity pneumonitis
  • Wegener’s granulomatosis
  • Churg Strauss (vasculitis)
  • Chronic eosinophilic pneumonia
  • Eosinophilic granuloma (Langerhan’s cell histoiocytosis)
  • Drug-induced lung disease
  • Sarcoidosis
  • Bronchiolitis obliterans
  • Lymphangioleiomyomatosis

The progression of ILD varies from disease to disease and from person to person. It is important to determine the specific form of ILD in each person because what happens over time and the treatment may differ depending on the cause. Importantly, each person responds differently to treatment, so close monitoring during treatment is important.