Everybody knows that smoking causes lung cancer. Government warnings and graphic photographs on cigarette boxes have driven home this important message. We also know that smoking is a major cause of heart disease and stroke.
However, there is yet another major disease, Chronic Obstructive Pulmonary Disease (COPD), caused by cigarette smoke which, although not uncommon, is less well-emphasised to the public.
The word ‘chronic’ means longstanding. ‘Pulmonary’ refers to the lung. In COPD, there is lung damage and airway inflammation caused by long-term exposure to noxious gases and particles. In Singapore, the single most important cause is cigarette smoking. Other causes include secondhand smoke, industrial pollution and a rare genetic condition known as alpha-1 antitrypsin deficiency where there is a lack of an enzyme important for the repair of lung tissue.
COPD, although not cancer, causes much disability and many deaths. In 2000, the World Health Organization estimated that 2.74 million people died of COPD. By the year 2020, COPD is estimated to be the 5th leading cause of death in the world. As compared to heart disease and stroke, it is the only major illness where the death rate is still increasing.
Prolonged exposure to cigarette smoke causes narrowing of airways (called bronchioles) and copious phlegm production due to changes in the mucous glands of the airway lining. Air has difficulty entering the lungs due to this obstruction, and the person makes a wheezing sound during breathing not unlike an asthmatic. This airway disease is called chronic bronchitis.
Smoke also damages the lung air sacs (alveoli) whose walls break down. This results in a loss of lung tissue and the lung becomes less ‘spongy’. The affected person has difficulty absorbing oxygen and ends up feeling ‘winded’ all the time. This lung tissue disease is called emphysema.
Chronic bronchitis and emphysema are the two components of the smokeinduced lung disease called COPD.
The four symptoms of COPD are:
COPD can be confirmed by performing a test called spirometry. In this test, an individual is asked to blow hard into a machine, which analyses the amount of air expired and the time required to do so.
Airway narrowing, coupled with loss of air sacs whose elastic recoil normally expels air out of the lungs, causes COPD patients to have air trapped in their lungs. In established cases, patients appear ‘barrel-chested’ and this hyperinflation can be seen on chest x-ray.
The most important thing to do is to stop smoking, regardless of how long you have smoked or how much. This is simply critical to your well-being. Studies have shown that stopping smoking at any stage of COPD will slow down the deterioration in lung function.
COPD when advanced is not a curable disease. Structural lung damage cannot be restored once it has happened. However, there are medications available which help to relieve symptoms and slow the progression of disease.
An important class of medications are bronchodilators, agents which open up the airways. These are usually inhaled and sometimes taken orally. Examples include salbutamol, theophylline, ipratropium, salmeterol, formoterol and tiotropium.
Another class of medications are glucocorticoids, also called simply ‘steroids’. These are prescribed in inhaled, oral or injectable forms. Oral and injectable steroids are used only on a short-term basis to control exacerbations so as to avoid steroid side effects.
These treatment strategies are similar to that employed for an asthmatic. However, for asthmatics, the condition is reversible as the airways go back to normal after an ‘attack’, whereas in COPD, the airways are permanently narrowed and lung sacs destroyed, thus drugs are able to act to a limited extent only.
Due to damaged lung architecture, copious sputum which easily gets infected, and damaged airway lining less resistant to micro-organisms, COPD patients are prone to fever and chest infections which often require antibiotics and even hospitalisation.
Other treatment options include pulmonary rehabilitation, exercise regimes designed to maximise the lung capacity. Home and portable oxygen can also be given.
When medications, oxygen and exercise fail, surgical options such as lung volume reduction surgery and even lung transplantation can be considered.
However, such drastic surgical methods are only suitable for a minority of patients. Unfortunately by the time symptoms are advanced, death will eventually occur from insurmountable breathing difficulties.
A cough in a smoker may not be a simple case of ‘smoker’s cough’. It may be the start of early COPD. If you are a smoker with any of the four symptoms - persistent cough, wheeze, persistent sputum production and shortness of breath, seek advice from your doctor as to whether COPD has developed.
Quitting smoking early can help curtail the progression of this deadly disease and prevent you from becoming what is called a ‘respiratory cripple’, someone who can hardly walk or do much because of breathlessness.
If you need help to strengthen your resolve to quit, contact your doctor. Many hospitals and clinics offer smoking cessation programmes with medical advice coupled with behavioral modification strategies and new anti-smoking drugs to make your effort more successful and sustained.
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