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Emphysema is a disease in which lung tissue is destroyed. The air sacs at the end of the respiratory passages lose their elasticity, making it difficult to breathe carbon dioxide out of the lungs. Tissue destruction causes the smallest airways to become narrower, which also decreases airflow. These changes mean the effect of emphysema on breathing is to cause shortness of breath and wheezing, with difficulty breathing out. As the disease progresses, loss of elasticity causes the lungs to overinflate, the chest wall becomes barrel-shaped, and the diaphragm flattens, so breathing becomes rapid and inefficient.
Since some of the air sacs no longer function, the effect of emphysema on breathing means there is less lung tissue available for oxygen to be taken up into the blood. Blood oxygen levels fall, causing fatigue and reducing the ability to exercise. Coughing is a common emphysema symptom, together with production of phlegm, and respiratory infections may occur, further worsening breathing. In the more advanced emphysema stages, even simple activities can cause breathing difficulties, and the disease, which may have been ignored until that point, becomes quite disabling.
The causes of emphysema include smoking and a hereditary condition known as alpha-1 antitrypsin deficiency. Alpha-1 antitrypsin is a protein which helps to protect the lungs from damage, but it is only deficient in around 1 or 2 percent of people with emphysema, and smoking is by far the main cause. Smoking and emphysema are commonly associated because the chemicals in cigarette smoke irritate lung tissues, leading to destruction of the elastic structural fibers, the smaller air passages and the air sacs. This loss of normal lung tissue results in the characteristic effects of emphysema on breathing.
Emphysema treatment first involves giving up smoking to prevent the disease from progressing. A number of medications are available which can help to counteract the effects of emphysema on breathing, including bronchodilators which widen the airways and steroids which reduce inflammation in the lungs. Where oxygen levels in the blood are low, an oxygen supply may be required and, if there is infection, treatment with antibiotics will be needed.
For patients with alpha-1 antitrypsin deficiency, regular alpha-1 antitrypsin infusions can be given into a vein. Surgery is reserved for cases of emphysema where all other treatment has failed. An operation called lung volume reduction may be carried out, where damaged areas of lung tissue are removed, reducing lung size and improving some of the adverse effects of emphysema on breathing. Emphysema prognosis depends on how far the disease has progressed, but giving up smoking is the most effective way to improve the outlook.