Pulmonary fibrosis

Pulmonary fibrosis (literally "scarring of the lungs") is a respiratory disease in which scars are formed in the lung tissues, leading to serious breathing problems. Scar formation, the addition of extra fibrous connective tissue (the process called fibrosis), leads to thickening of the walls, and causes low oxygen supply in the blood.
As a result patients suffer from shortness of breath.
In some patients the cause of the disease can be diagnosed, but in others the cause is unknown, a condition called idiopathic pulmonary fibrosis. There is no known cure for the scars and damage in the lung due to pulmonary fibrosis.