Complications

Pneumonitis that goes unnoticed or untreated can cause irreversible lung damage.

In normal lungs, the air sacs stretch and relax with each breath. Chronic inflammation of the thin tissue lining each air sac causes scarring and makes the sacs less flexible. They become stiff like a dried sponge. This is called pulmonary fibrosis. In severe cases, pulmonary fibrosis can cause right heart failure, respiratory failure and death.