Proper expansion of the lungs may be restricted by diseases of the nerves or muscles that control expansion or by diseases of the pleura. Finally, tumors or large amounts of fluids in or around the lung may interfere with its movement and reduce the volume of lung available for breathing. The most common infection of the lower respiratory tract, bronchitis, is a result of inflammation of the airway, and can be caused by bacteria or a virus. Pneumonia, which can be caused by bacteria, viruses, fungi, or parasites, also results in inflammation of the airways and alveoli. Recurrent or chronic respiratory infections may plague people with certain chronic lung diseases, such as cystic fibrosis or bronchiectasis.
Lung cancer is the leading cause of cancer death in both men and women.
Its symptoms may include a persistent cough, bloody sputum, chest pain, and recurring pneumonia or bronchitis. However, symptoms may be absent until very late in the course of the disease. When it is discovered in advanced stages, the cure rate is generally low. Cigarette smoking is the major risk factor for the development of lung cancer. Diseases of blood vessels in the lungs.