Chronic obstructive pulmonary disease (COPD) is a descriptive medical term for a number of similar overlapping diseases that include chronic bronchitis, emphysema and some chronic asthma that has become resistant to treatment. These conditions have in common a persistent and slowly progressive pattern of symptoms such as shortness of breath, cough and wheeze. In particular, on formal measurement they all share reduced flow of air through the bronchial tubes, due to narrowing or damage.

Chronic bronchitis means having a cough with sputum for at least three months a year for two consecutive years. In its mildest form this could simply be a smoker’s cough in the morning with small amounts of sputum. Severe chronic bronchitis, on the other hand, involves a much greater degree of cough and sputum linked with shortness of breath, wheeze and frequent episodes of acute bronchitis, especially during the winter months. Chronic bronchitis relates to producing excess amounts of phlegm with narrowing of breathing tubes.

Emphysema can be more difficult to diagnose clinically until more advanced. The symptoms are shortness of breath with wheeze and chest tightness. They are caused by permanent damage to the small breathing tubes and air sacs where oxygen and carbon dioxide are exchanged with the blood.

Chronic bronchitis and emphysema often occur in the same patient. Both conditions tend to start after the age of 50 and are more common in men than women.

What causes COPD?

By far the most common cause is cigarette smoking. Generally, the greater the tobacco exposure the greater the risk of developing CPD. About 15% of smokers will develop symptoms of COPD but what makes this group susceptible to cigarette smoke compared with other smokers is not at present understood. Other risk factors for COPD are working in dusty environments or, possibly, living in industrialised large cities. Rarely, emphysema is a result of a inherited deficiency of protective protein called alpha-1—antitrypsin.

How common is it and how does it progress?

After the age of 50, COPD causes an increasing number of visits to GPs and hospital - in one survey, 12% of all medical hospital admissions were due to COPD.

The progression of COPD, while smoking continues, is one of steady deterioration towards increasing disability and death. In 1992 there were 26033 deaths in England and Wales from COPD.

If patients stop smoking, symptoms and lung damage remain largely unchanged. Unfortunately, damage to the lung does not repair itself. But the progression to disability does not occur, and any deterioration thereafter is slight and no different from a non-smoker. Sometimes, if the main symptom is cough and sputum, this may completely resolve.