HEALTHNET

What is Chronic Obstructive Pulmonary Disease - Part I

Chronic obstructive pulmonary disease is a chronic lung disease which is characterized by obstructive to airflow that interferes with normal breathing.

(Posted on 26 July 2007)

Chronic obstructive pulmonary disease is a chronic lung disease which is characterized by obstructive to airflow that interferes with normal breathing. Chronic obstructive pulmonary disease includes two main illnesses: chronic bronchitis and emphysema. These two diseases have similar symptoms and are collectively known as "chronic obstructive pulmonary diseases" or COPD in short.

Chronic Bronchitis

Our lungs have two main parts: the bronchi and the alveoli. When we breathe in through our mouths or noses, the air moves through the bronchi and into the alveoli. Under normal respiration, oxygen from the air will enter the bloodstream by diffusion through the walls of the small blood vessels (capillaries) from the alveoli while carbon dioxide will pass into the alveoli from the blood at the same time. Prolonged exposure to irritants will cause the bronchi to produce an excessive amount of mucous constantly, which will obstruct the airways. Chronic bronchitis is defined by the presence of a mucus-producing cough most days of the month, three months of a year for two successive years without other underlying diseases to explain the cough.

Emphysema

Emphysema is a form of lung disease related to bronchitis. Prolonged irritation of the lungs causes frequent inflammation of the bronchi and alveoli, which leads to the enlargement of the alveoli and ultimately the loss of elasticity by the lung tissue. Since walls of the alveoli are destroyed, the lungs are able to transfer less and less oxygen to the blood stream, causing shortness of breath. Emphysema can also be caused by the inherited deficiency of a protein called alpha-one antitrypsin (AAT). AAT finds in the serum which acts to protect the lungs. This is called "alpha-one antitrypsin deficiency". Such a condition often occurs after middle age when emphysema may arise even without exposure to the usual irritants such as smoking tobacco.

Causes of COPD

Smoking is the primary risk factor for COPD. The more one smokes, the higher is one's risk. Other risk factors of COPD include second-hand smoke, air pollution, airways hypersentivity and alpha-one antitrypsin deficiency.

What are the symptoms of COPD?

The most common symptoms include chronic coughing, shortness of breath, and the production of excessive amounts of sputum. If you are smokers and have the above symptoms, you are advised to consult doctor promptly because you may already suffer from COPD or other lung diseases.

Source: Hong Kong and Drug Education Resources Centre, The Society of Hospital Pharmacists of Hong Kong