Chronic obstructive pulmonary disease (COPD) kills nearly three million people each year. About 600 million people around the world are affected by COPD.
In the Asia Pacific region, it is estimated that over 56 million people suffer from moderate to severe form of this disease. COPD is currently the fourth leading
cause of death in the world and it is expected to be the third by 2020. The COPD burden is projected to increase in coming decades because of continued exposure to
COPD risk factors and aging of population. It is an important public health challenge that is both preventable and treatable.
COPD is a debilitating disease which affects the lungs and airways, causing airflow obstruction which is not reversible. It includes two sub-conditions: chronic
bronchitis and emphysema. A COPD patient may have one or both of these conditions.
COPD patients differ from asthmatic patients as they usually are heavy smokers with a long smoking history, onset after age 40 years, symptoms progressive over
time and not associated with allergies.
Cigarette smoking is the main risk factor. The genetic risk factor is severe hereditary deficiency of alpha-1 antitrypsin. However, this is relevant to a small
part of the world’s population. Exposure to other types of tobacco like pipe, cigar and marijuana can cause COPD. Occupational exposures including organic and inorganic dusts,
chemical agents and fumes are also risk factors. Indoor air pollution from biomass and coal cooking and heating in poor ventilated dwellings is an important risk factor. High levels
of urban air pollution are harmful.
How COPD affects the lungs and airways:
The muscles around the airways constrict and more mucus is produced in the airways leading to blockage.
The air sacs walls break down, leaving less surface area for exchange of carbon dioxide and oxygen. The air sac wall also loses elasticity causing air trapping.
The combination of these two factors causes air to be trapped in the lungs so carbon dioxide is not completely exhaled. This leaves less room for oxygen to be inhaled. The patients become increasingly breathless and unable to perform physical activity and other activities of daily living.
Symptoms of COPD:
- Chronic cough
- Chest tightness
- Sputum production
In the early stage, COPD can be asymptomatic until more than 50% of function is decreased, the patient will start to experience the shortness of breath.
COPD should be considered in any patient who has dyspnoea, chronic cough or sputum production, and/or history of exposure to risk factors for the disease. Spirometry is required to make the diagnosis in this clinical context.
Additional Investigations for diagnosis and assessment of severity include:
- Chest x-ray to exclude other diagnoses. Changes associated with COPD include signs of hyperinflation.
- CT scan thorax is not routinely done. It can exclude other diagnosis like bronchiectasis. It would show the emphysematous changes and distribution in COPD.
- Lung volumes and diffusion capacity. COPD patients exhibit gas trapping from early stages of the disease. As the airflow limitation worsens, the total lung capacity increased. These measurements help to characterize the severity of COPD. Measurement of diffusion capacity provides the functional impact of COPD.
- Oximetry and arterial blood gas are used to evaluate the oxygen saturation and need for supplemental oxygen therapy.
Treatment and management
- Lung function naturally declines as a person gets older. However the decline is accelerated when a person smokes. It is important to quit smoking to slow down the process of lung function decline.
- These open up the airways. They make them less short of breath, reduce severe episodes requiring hospitalisation, will improve on the quality of life.
- The short acting bronchodilators are used as reliever medication for quick relief from acute symptoms of COPD.
- Long acting bronchodilators are used daily for maintenance treatment in moderate to severe COPD
- These are either anticholinergics or beta2 agonists. They work through different pathways to open up the airways.
- Antibiotics for infective exacerbations
- Anti-inflammatory medicines during exacerbations
- Long term oxygen therapy
- Pulmonary rehabilitation
Breathlessness does not only limit the physical activity but may have an emotional impact. They may feel frustrated, lonely and depressed as
they cannot keep up with the social activities and hence reduce interactions with family and friends. As they get worse, they may even need help with simple
daily tasks. Their quality of life would be affected.
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