Chronic obstructive pulmonary disease (COPD) also known as chronic obstructive lung disease (COLD) or chronic obstructive airways disease (COAD) is a medical condition characterized inadequate air flow in the lungs. This is a progressive disease which gradually worsens over time. Common presenting symptoms include respiratory difficulty, cough with production of sputum.

COPD includes two other medical conditions chronic bronchitis and emphysema. Chronic bronchitis is characterized by inflammatory damage to the lining of the airways whereas in emphysema characterized by progressive damage to the sac like structures (alveoli or air sacs) at the terminal part of the air passages (the bronchioles). The most common factor associated with COPD is tobacco smoking; other common associated factors include exposure to different air pollutants and having certain genetic factors. The most common source of air pollution in the developing countries is the poorly aerated cooking and heating fires.

The incidence of COPD can be reduced to some extent by quitting smoking, improving the outdoor as well as indoor air quality etc. There is no cure available for COPD however several treatment options are available which can effectively control the symptoms of the disease. These include inhalation of steroids, bronchodilators, theophyllines and oral antibiotic drugs. In some of the patients of COPD oxygen therapy for long time along, lung transplantation etc are required. During periods of acute exaggeration of symptoms increase use of the drugs along with hospitalization is required, thereby increasing the economic burden on individual as well as social level. In the year 2010 the disease cost  around $2.1 trillion. COPD is a common disease; around the world about 5% of the total population suffers from this condition (about 329 million people). In the year 2012 it is ranked as the third most important cause of death worldwide (about 3 million people are killed).

Symptoms
Usually the symptoms of COPD do not become evident until and unless there is lung damage to a certain degree and once evident the symptoms gradually worsen over years. The most common presenting symptoms of COPD include
1) Difficulty in breathing usually after physical exertion
2)  noisy breathing (wheezing)
3)  feeling of tightness of the chest
4) Cough with sputum production. In COPD the cough characteristically occur in the morning usually after waking up. The patient has to clear the throat of excess mucous first thing in the morning. The sputum produced during coughing is either white to yellowish in color or greenish
5) Bluish discoloration (cyanosis) of the finger tips or tips of the tongues due to low oxygen level in the blood. In COPD there is abnormality in the air exchange process across the air sacs of the lungs hence there is inadequate oxygenation of different organs and to different parts of the body.
6) Increased tiredness, fatigue
7) Loss of body weight
In the patients of COPD there are acute exacerbation of all the preexisting symptoms requiring prompt and intensive therapy with increased dose of drugs already in use and antibiotics.
Common complications associated with COPD include
1) Repeated episodes of chest infection at short intervals: COPD patients are at increased risk of suffering from cold, flu, pneumonia etc. Hence in these patients early flu vaccination and pneumococcal vaccination at regular intervals help in prevention of some of the episodes of chest infection
2) Heart problems: there is high pressure in the lung arteries in patients of COPD which in turn puts on stress on the right ventricle of the heart leading to a heart condition known as cor pulmonale. In cor pulmonale there is swelling of legs, bulging of neck veins etc. Currently the incidence of cor pulmonale is much less with oxygen supplementation.
3) Patients of chronic bronchitis as part of COPD have increased risk of suffering from lung cancer in the future
4) Depression: inability to breath comfortably and adequately may lead to depression in some of the patients of COPD thus requiring professional help.