A CHRONIC DISORDER of breathlessness, chest tightness, wheeze, sputum production, cough, frequent chest infections and reduced ability to exercise. In many of those with the condition, smoking has been the precipitating cause. Symptoms and signs of emphysema, chronic bronchitis and asthmatic bronchitis overlap, making it difficult sometimes to make a precise diagnosis. Many patients with COPD also have ASTHMA but the pure form of the latter is different because it is reversible – that is it gets better and worse with time (asthma attacks) or the acute symptoms and signs can be reversed by BRONCHODILATORS. In particular, in COPD the cough tends to be persistent and productive of sputum, the shortness of breath gets steadily worse over years and – unlike asthma – patients do not feel worse at night. The term has come to include chronic BRONCHITIS, EMPHYSEMA, and chronic ASTHMA, where the airflow into the lungs is obstructed.
Chronic bronchitis is typified by chronic productive cough for at least three months in two successive years (provided other causes such as TUBERCULOSIS, lung cancer and chronic heart failure have been excluded). The characteristics of emphysema are abnormal and permanent enlargement of the airspaces (ALVEOLI) at the furthermost parts of the lung tissue. Rupture of alveoli occurs, resulting in the creation of air spaces with a gradual breakdown in the lung's ability to oxygenate the blood and remove carbon dioxide from it (see LUNG). Asthma results in inflammation of the airways with the lining of the BRONCHIOLES becoming hypersensitive, causing them to constrict. The obstruction may spontaneously improve or do so in response to bronchodilator drugs. If an asthmatic patient's airway obstruction is characterised by incomplete reversibility, he or she is deemed to have a form of COPD called asthmatic bronchitis; sufferers from this disorder cannot always be readily distinguished from those people who have chronic bronchitis and/or emphysema. The prevalence of COPD has been increasing, as has the death rate. In the UK around 30,000 people with COPD die annually and the disorder makes up 10 per cent of all admissions to hospital medical wards, making it a serious cause of illness and disability. The prevalence, incidence and mortality rates increase with age, and more men than women have the disorder, which is also more common in those who are socially disadvantaged.
The most important cause of COPD is cigarette smoking, though only 15 per cent of smokers are likely to develop clinically significant symptoms of the disorder. Smoking is believed to cause persistent airway inflammation and upset the normal metabolic activity in the lung. Exposure to chemical impurities and dust in the atmosphere may also cause COPD.
Most patients develop inflammation of the airways, with excessive growth of mucus-secreting glands and changes to other cells. The result is that mucus is transported less effectively along the airways to eventual evacuation as sputum. Small airways become obstructed and the alveoli lose their elasticity. COPD usually starts with repeated attacks of productive cough, commonly following winter COLDS; these attacks progressively worsen and eventually the patient develops a permanent cough. Recurrent respiratory infections, breathlessness on exertion, wheezing and tightness of the chest follow. Bloodstained and/or infected sputum are also indicative of established disease. Among the symptoms and signs of patients with advanced obstruction of airflow in the lungs are:
RHONCHI (abnormal musical sounds heard through a STETHOSCOPE when the patient breathes out).
marked indrawing of the muscles between the ribs and development of a barrel-shaped chest.
loss of weight.
CYANOSIS in which the skin develops a blue tinge because of reduced oxygenation of blood in the blood vessels in the skin.
bounding pulse with changes in heart rhythm.
OEDEMA of the legs and arms.
decreasing mobility.
Some patients with COPD have increased ventilation of the alveoli in their lungs, but the levels of oxygen and carbon dioxide are normal so their skin colour is normal. They are, however, breathless and so have been called in the past ‘pink puffers’ as opposed to those who have reduced alveolar ventilation which lowers their oxygen levels causing cyanosis; they also develop COR PULMONALE, a form of heart failure, and become oedematous, so were historically known as ‘blue bloaters’.
include various tests of lung function, including the patient's response to bronchodilator drugs. Exercise tests may help, but radiological assessment is not usually of great diagnostic value in the early stages of the disorder.
depends on how far COPD has progressed. Smoking must be stopped – also an essential preventive step in healthy individuals. Early stages are treated with bronchodilator drugs to relieve breathing symptoms. The next stage is to introduce steroids (given by inhalation). If symptoms worsen, physiotherapy – breathing exercises and postural drainage – is valuable and annual vaccination against INFLUENZA is strongly advised. If the patient develops breathlessness on mild exertion, has cyanosis, wheezing and permanent cough and tends to HYPERVENTILATION, then oxygen therapy should be considered. Antibiotic treatment is necessary if overt infection of the lungs develops.
Sometimes rupture of the pulmonary bullae (thin-walled airspaces produced by the breakdown of the walls of the alveoli) may cause PNEUMOTHORAX and also exert pressure on functioning lung tissue. Respiratory failure and failure of the right side of the heart (which controls blood supply to the lungs), known as cor pulmonale, are late complications in patients whose primary problem is emphysema.
This is related to age and to the extent of the patient's response to bronchodilator drugs. Patients with COPD who develop raised pressure in the heart/lung circulation and subsequent heart failure (cor pulmonale) have a bad prognosis.