Chronic obstructive pulmonary disease, commonly known as COPD, is a disease that makes it hard to breathe. It is a progressive disease, which means the disease gets worse over time. COPD can cause wheezing, shortness of breath, chest tightness, and coughing that produces large amounts of mucus. It is caused by damage to the lungs over many years, and usually develops as a result of smoking. There is no cure for COPD, and it is impossible to undo the damage to the lungs, but there are steps to prevent further damage and to feel better. COPD is often a mix of two diseases: chronic bronchitis and emphysema.

Chronic bronchitis is a persistent respiratory disease in which the mucus membranes in the bronchial passages of the lungs become inflamed. As the membrane becomes irritated, it swells and grows thicker and narrows or shuts off the airways in the lungs resulting in coughing spells. These coughing spells may be accompanied by phlegm and loss of breath. Chronic bronchitis is a serious long-term disorder that requires regular medical treatment.

Emphysema is a long-term lung disease in which the alveoli (tiny air sacs) at the end of the airways are damaged. When those sacs are damaged or destroyed, the walls break down and the sacs become larger. The sacs then move less oxygen into the blood. This causes difficulty breathing or shortness of breath. Air sacs that are destroyed cannot be replaced.

While a productive cough and shortness of breath are the most common and present symptoms of COPD, there are other symptoms and effects of COPD on the body. With COPD, individuals may take longer to breathe out than breathe in. Advanced COPD can lead to high pressure on the arteries in the lung, which can strain the right ventricle of the heart. This is called corpulmonale and can lead to leg swelling and bulging neck veins. Corpulmonale is more common to be caused by COPD than any other lung disease. However, with the use to supplemental oxygen, corpulmonale can be reduced.

Due in part to shared risk factors, COPD often occurs along with other conditions such as heart disease, high blood pressure, diabetes, and osteoporosis. Those with severe COPD tend to constantly feel tired and lethargic.

COPD affects nearly 5% of the global population - around 329 million people. It ranked as the third-leading cause of death in 2012, killing over 3 million people. The number of deaths due to COPD is expecting to increase due to higher smoking rates and an aging population. In 2010, it resulted in an estimated economic cost over $2 trillion.

Tobacco smoking is the leading cause of COPD, but there are other factors that can result in the disease. Air pollution and genetics can play a small role in the development of COPD. In the developing world, one of the most common sources of air pollution is from poorly vented cooking and heating appliances and fires. Long-term exposure to these irritants causes emphysema, which is one of the diseases common in COPD. COPD can be prevented. By reducing exposure to known causes of COPD, individuals can lengthen the lifespan of their lungs.

Poorly ventilated cooking fires fueled by coal or biomass fuels such as wood or animal dung, lead to indoor air pollution. These fires are a method of cooking and heating for almost 3 billion people and their health effects are greater among women due to increased exposure. In China, India, and sub-Saharan Africa, these fires are used as a main source of energy in 80% of homes.

People who live in large cities as opposed to rural areas have a higher rate of COPD due to urban air pollution. It is not clear if urban air pollution is a root cause of COPD, but it is confirmed to be a tremendous exacerbation cause. The overall effect, compared to smoking, is believed to be small.

It's not only smoking or pollution that can place people at higher risk of COPD. Prolonged exposure to workplace dusts, chemicals, and fumes can also increase the risk in smokers and nonsmokers alike. Exposures in the workplace are believed to be the cause in 10-20% of cases of COPD. In the United States, they are believed to be one of the leading causes of COPD in nonsmokers.

Diagnosis of COPD should be considered in anyone over the age of 35 who has the symptoms of COPD, especially if they have a history of exposure to risk factors. Confirmation of a COPD diagnosis utilizes spirometry. After the use of a bronchodilator, a medication to open the airways, spirometry measures the amount of airflow obstruction present in the lungs. The two main components measured to make the diagnosis are the forced expiratory volume in one second (the greatest volume of air that can be breathed out in the first second of a breath) and the forced vital capacity (the greatest volume of air that can be breathed out in a single large breath). In a healthy person, 75-80% of the FVC comes out within the first second, but a ratio of less than 70% in someone with the symptoms of COPD defines the person as having the disease.

The COPD assessment test is a simple questionnaire that may be used to determine the severity of COPD symptoms in individuals. Scores on the CAT range from 0-40 with a higher score indicating a higher severity of symptoms. There are several grades for defining the severity of COPD. The GOLD grades indicates the predicted FEV percentage, with over 80% defining a mild case of COPD to less than 30% indicating very severe COPD and chronic respiratory failure. The MRC shortness of breath scale measures from 1-5 from activity such as changing of clothing affecting shortness of breath to shortness of breath only with strenuous activity.

Preventing COPD starts with never smoking or cessation of smoking. Public policy and relieving societal pressures on individuals to smoke are fundamental to preventing young people from beginning to smoke. Smoking bans in public areas and places of work are important policies to decrease exposure to secondhand smoke. For those who smoke, ceasing smoking can delay the onset of disability and death.

Management of COPD includes exercise, medications (including bronchodilators as the primary type of medication and cortisteroids to decrease acute exacerbations in those with moderate to severe COPD), antibiotics, supplemental oxygen (which can decrease the risk of heart failure and death if used 15 hours per day), and surgery in the case of those with very severe disease.