Chronic Obstructive Pulmonary Disease (COPD) is an umbrella term used to describe progressive lung diseases, including emphysema, chronic bronchitis, refractory (non-reversible) asthma, and some forms of bronchiectasis. It develops slowly over many years and you may not be aware that you have it at first.
COPD occurs when the lungs become inflamed, damaged and narrowed. Most cases of COPD are caused by smoking, although the condition can sometimes affect people who have never smoked. You're more likely to develop COPD if you smoke and have smoked for a long time. Some cases of COPD are caused by long-term exposure to harmful fumes or dust, or occur as a result of a rare genetic problem that means the lungs are vulnerable to damage.