Lung disease is any problem in the lungs or that prevents the lungs from working properly. There are three main types of lung disease:
Airway diseases -- These diseases affect the tubes (airways) that carry oxygen and other gases into and out of the lungs. These diseases usually cause a narrowing or blockage of the airways. They include asthma, emphysema, bronchiectasis, and chronic bronchitis. People with airway diseases often say they feel as if they are "trying to breathe out through a straw."
Lung tissue diseases -- These diseases affect the structure of the lung tissue. Scarring or inflammation of the tissue makes the lungs unable to expand fully ("restrictive lung disease"). This makes it hard for the lungs to take in oxygen and release carbon dioxide. People with this type of lung disorder often say they feel as if they are "wearing a too-tight sweater or vest" that doesn't allow them to breath deeply. Pulmonary fibrosis and sarcoidosis are examples of lung tissue disease.
Lung circulation diseases -- These diseases affect the blood vessels in the lungs. They are caused by clotting, scarring, or inflammation of the blood vessels. They affect the ability of the lungs to take up oxygen and to release carbon dioxide. These diseases may also affect heart function.
Many lung diseases involve a combination of these three types.
Kraft M. Approach to the patient with respiratory disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 83.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.