Interstitial lung disease (ILD) is the result of over 200 etiological pathways arising from several different insults to the lung parenchyma: inhaled substances, drug side effects, connective tissue disease, infection, and malignancy. The disease can also be of idiopathic origin. If prolonged, the resulting inflammation causes permanent and progressive fibrotic reorganization of the parenchyma and small airways, which reduces the distensibility of the lung and impedes O2 and CO2 exchange.