Chronic obstructive pulmonary disease (COPD) is a medical condition characterized by shortness of breath and cough with sputum production. The symptoms of COPD gradually deteriorate over years and worldwide it is ranked as the third most common disease leading to death.Although there is no permanent cure for COPD, drugs like corticosteroids, bronchodilators etc are available to relieve the symptoms. The symptoms of COPD can also be improved following quitting tobacco smoking, avoidance of exposure to different air pollutants etc.

Causes
The most common underlying cause of COPD is exposure to tobacco smoke; however the disease occurs in women especially those of the developing countries due to exposure to the smoke generated from burning fuel used for the purpose of cooking and heating. It is estimated that about 20% of the chronic smokers develop the symptoms of COPD.Normally the inhaled air travels down the windpipe (the trachea) which then divides into two divisions (two tube like structures) known as the bronchi.

The two bronchi enter the two lungs respectively and further divide into smaller branches known as the bronchioles. The terminal parts of each of bronchioles take the shape of sac known as alveoli. The walls of the alveoli are very thin and are full of small blood vessels. Thus the inhaled air passes through the trachea, the bronchi, the bronchioles and ultimately reaches the alveoli. Next exchange of oxygen occurs between the air present in the inhaled air (in the alveoli) and the blood circulating in the small blood vessels surrounding the alveolar sac. At the same time carbon-Di-oxide present in the small blood vessels enters the alveolar sac and is exhaled outside in the environment following the same path as the inhaled air but only in the reverse way.

In COPD the natural elasticity of the air sacs are compromised leading to trapping of air in the lungs and hence the resultant symptoms.In COPD either of the two main clinical situations may arise. These are emphysema and chronic bronchitis. In emphysema the elastic nature of the alveolar wall is lost leading to collapse of the alveoli, inadequate exchange of air and symptoms of COPD. Whereas in chronic bronchitis the airways become narrow following inflammation and making the condition worse the lungs produce large amount of mucous blocking the already narrow airways further and hence the symptoms.

Cigarette smoking is one of the most important factors leading to COPD. Exposure to tobacco smoke may occur due to pipe smoking, cigar smoking, second hand smoking, passive smoking, exposure to air pollutants, dust, fumes etc.Other than exposure to tobacco smoke genetic factor may also play an important role in COP. In about 1% of the patients of COPD there is deficiency of a particular protein alpha 1 antitrypsin. This particular protein is synthesized in the liver and secreted in the blood circulation. It is responsible for protection of the lung tissue. Hence deficiency of this protein may lead to loss of elasticity of the lung tissue and the symptoms of COPD. Furthermore it can also lead to symptoms related to damage to the liver. These symptoms can affect both adults as well as children. Treatment of COPD due to alpha 1 antitrypsin deficiency is same as COPD without any genetic defect.

Risk factors
Common risk factors associated with
1) Chronic exposure to tobacco smoke: this is the most significant risk factor associated with COPD. Risk of COPD increases with the duration and packets of cigarettes smoked. Pipe smoking, cigar smoking, marijuana smoking and repeated exposure to passive smoking leads to increased susceptibility to COPD.
2) Asthma and cigarette smoking: cigarette smoking in asthma patients increases the risk of suffering from COPD.
3) Prolonged exposure to dusts, fumes, industrial air pollutants increases the risk of suffering from COPD in future.
4) Age: COPD is slowly progressing diseases hence the symptoms of this disease usually become evident between 35 and 40 years.
5) Genetic factor: rare genetic defect like deficiency of the protein alpha 1 antitrypsin increases the risk of suffering from COPD especially if the said person smokes.

Treatment
Although there is no permanent cure available for COPD, however current treatment modalities can effectively relieve the severity of the symptoms, episodes of exacerbation of already existing symptoms, long term complications and thus increases the chance of living normal life.
There are several drugs used to relieve the symptoms and reduce the episodes of exacerbation of symptoms. These are
1) Bronchodilator usually administered through inhalational route. These drugs include mainly beta agonists namely salbutamol, salmeterol etc, anticholinergic drugs like ipratropium bromide etc.
2) Corticosteroids: administered either via inhalational route or oral route.
3) Combination of steroids and long acting beta agonists like combination of fluticasone and salmeterol respectively.
4) Theophylline
5) Antibiotics to manage the associated bacterial lung or airway infection (upper or lower respiratory tract infection)
Other associated treatment options for COPD patients include
1) Oxygen therapy
2) Pulmonary rehabilitation program like education, breathing exercise, specific nutritional advice and counseling.
Surgery is an important treatment options in COPD patients with severe degree of emphysema. The surgical treatment options include lung volume reduction surgery (removal of damaged part of the lung so that remaining normal portion of the lung can work more effectively) and lung transplant.