Do you ever have the following problems?
- Daily cough and phlegm for at least three months a year for a number of years.
- Excessive and prolonged coughing after the flu or a cold.
- Progressive shortness of breath during daily activities that was not a problem before.
- Wheezing attacks during the nighttime or after exercise.
If you have any one of the above problems and are or have been a smoker, you may be suffering from Chronic Obstructive Pulmonary Disease (COPD)!!
What is COPD?
COPD is a chronic, progressive, airway disease characterized by airflow limitation; it comprises chronic bronchitis and emphysema. The sufferers of the disease have narrow small airways and difficulty in getting air in and out of their lungs. The forced expiratory flow volume in one second (FEV 1 ), which is a measure of lung function, of COPD patients falls at a rate three to four times that of the normal non-smokers. Since the symptoms of COPD are rather non-specific, most patients present late in the course of their disease.
Burden of COPD
There is a rising trend in the global incidence of COPD. The WHO estimated the disease will be the 5th commonest disease and the no. 3 killer in the world by 2020.
Although the exact prevalence of the disease is not known in Hong Kong, a local study suggested 9% of the elderly above the age of 70 are its victim. From statistics of the Hospital Authority, COPD was the cause of 4% of all urgent hospital admissions in 1997 and contributed 5.8% of all deaths in the same year.
Causes of COPD
There is no doubt that cigarette smoke causes COPD. As a matter of fact, 90% of patients are either current or ex-smokers. It is thought that cigarette smoke induces inflammation in the small airway and lung substance. An excessive amount of enzyme (protease) is produced which stimulates mucus secretion, which damages the airway walls and lung tissues and destroys the local immune system. After many years of inhaling toxic cigarette smoke, the smoker will develop chronic bronchitis and emphysema. The chance of developing COPD correlates with the daily cigarette consumption and duration of smoking.
Air pollution and genetic factors may play a role in the causation of COPD in non-smokers.
Symptoms of COPD
- Cough and sputum: chronic productive cough is a hallmark of chronic bronchitis. It is due to excessive mucus production and airway wall thickening secondary to cigarette smoke. Affected subjects will have worsening of these symptoms after viral infection or deterioration of air quality.
- Shortness of breath: Feeling breathless is a late symptom when the FEV 1 has fallen by more than 50% from its peak value. As lung function gradually deteriorates, patients become more and more breathless on exertion or with daily activities. Finally the unfortunate patient has difficulty in breathing even at rest.
Investigation of COPD
- Early stages of COPD can be most cost-effectively diagnosed by spirometry – measuring FEV 1 and FVC (forced vital capacity). When the ratio of FEV 1 /FVC is persistently below 70%, chronic airflow obstruction is diagnosed.
- Chest X-ray is an insensitive method to diagnose COPD. Only advanced stages of emphysema will be revealed by chest radiography. Nevertheless, doctors order chest X-ray mainly to exclude other common lung diseases, like TB or lung tumours, which are associated with symptoms similar to those of COPD.
- Blood gas analysis: this invasive method is only reserved for patients who have features of oxygen deficiency, carbon dioxide retention or right sided heart failure. Blood gas should be measured to decide whether the patient needs long term oxygen treatment.
Treatment of COPD
- Smoking Cessation: It is mandatory that COPD patients should stop smoking. Quitting the habit will improve coughing and expectoration within one week. The FEV 1 of patients who stop smoking will decline at a lower rate approaching that of non-smokers. Thus, further symptom deterioration is postponed and the life of the patient prolonged. Heath care professionals can help smokers quit the habit by means of behavioral therapy, psychological support and drugs. Anti-smoking classes are organized regularly by various hospitals and government clinics.
- Pharmacotherapy: Though unable to alter the eventual outcome of the disease, medications are employed to improve symptoms and quality of life.
- Bronchodilators, being able to relax the smooth muscles of the airway and ameliorate airflow obstruction, are the principle therapeutic agents. Inhaled bronchodilators penetrate directly to the small airways and are thus more effective than the oral forms. A much smaller dose is needed in inhaled formulation and is associated with minimal side effects. The main disadvantage of inhaled bronchodilators is the requirement of hand-mouth coordination, which may prove to be difficult for the elderly. Various spacers have been used to overcome the problem. Once the patient has exacerbation of his/her disease, a larger dose of the bronchodilator can be nebulized and given to the patient to achieve maximal effects.
- Steroid : Whereas inhaled corticosteroid causes dramatic improvement in symptoms of asthmatic patients, its value in the treatment of COPD patients is very limited. Only 10-15% of stable COPD patients show an increase in their lung function after inhaled corticosteroid. However, an oral or intravenous corticosteroid hastens recovery when given to patients who have disease exacerbation (worsening of symptoms).
- Antibiotic : Prophylactic antibiotic is not useful in preventing exacerbation. Doctors would only prescribe antibiotic if patients have at least two of the following features:
(i) increase in shortness of breath
(ii) increase in sputum volume
(iii) increase in sputum purulence
COPD is a smoking-related, incurable and progressively deteriorating obstructive lung disease. Current medical treatment is by no means satisfactory. Smokers should stop smoking and be aware of early symptoms of COPD so that they can seek medical advice at an early stage of the disease. Affected individual must stop smoking and comply with treatment from health professional to obtain maximum benefits.
More information on COPD is available at the web site: http://www.copd.hk