Chronic Obstructive Pulmonary Disease or COPD–causes, symptoms, and more
Chronic obstructive pulmonary disease, (COPD) as the name implies, is a progressive inflammatory disease of the respiratory tract that causes a marked limitation of the airflow to the lungs. It has two main components, one being emphysema and the other one being chronic bronchitis. Both are present in almost all the COPD patients, but one may predominate over the other. Bronchitis and emphysema have distinct features that aid in their recognition.
Bronchitis is the inflammation of the bronchi (the large airways). Mucus hypersecretion from the airway lining epithelial cells and hypertrophy of the wall musculature occur as a direct response to inflammation. This causes a marked narrowing of the airways. Bronchitis may progress to involve the smaller airways causing bronchiolitis.
Emphysema primarily affects the terminal airways or the alveoli of the lungs. Alveoli are tiny air-filled sacs surrounded by capillaries. Their function is to exchange gas between the lungs and the blood. The inflammation and damage lead to irreversible dilatation and destruction of alveoli. These abnormally large alveoli may coalesce to form bullae. Bullae formation greatly reduces the surface area for the gas exchange in the lungs. Emphysema also may ascend to involve the smaller airways causing bronchiolitis.
Advanced COPD patients typically have bronchitis, bronchiolitis and emphysema occurring concurrently together.
Symptoms of COPD
COPD is a disease which has an insidious onset and progression. Most people are apparently well until they progress to the severe stages of the disease. The mild disease typically has no symptoms unless diagnosed by lung function tests.
The prominent symptoms differ according to the degree of bronchitis and emphysema. Those who have predominant bronchitis complain of daily cough and excessive sputum production. On the other hand, patients with predominant emphysema mainly complain of difficulty in breathing.
- Besides those, other symptoms seen in COPD patients are,
- Shortness of breath
- Wheezing particularly during exertion
- Chest tightness or chest pain
The following findings during physical examination increase the suspicion of COPD
- Barrel shape chest; the anteroposterior diameter of the chest is greater than the transverse diameter
- Tracheal tug – Adam’s apple moving up and down with respiration
- Pursed lip breathing; during the expiration, the person narrows the lips and sends air out as if he’s blowing a balloon.
- Prolonged expiration
- Wasted body
Risk factors and causes for COPD
By far the commonest risk factor is the exposure to tobacco smoke. Smoking is strongly associated with chronic bronchitis as well as with emphysema. Approximately 90% of the people who are suffering from COPD have a history of smoking.
Vehicle and cooking fumes and occupational dust are also thought to be associated with COPD.
Rarely genetic diseases like α-1 anti-trypsin deficiency may be the cause of emphysema.
Complications of COPD
COPD is a disease that has high morbidity and mortality. Even though it starts from the airways, as the disease advances many systemic complications occur.
- Recurrent respiratory tract infections are frequent among those who have predominant bronchitis.
- Pneumothorax (air outside the lungs, in-between the lung and chest wall) can occur as a consequence of bullae rupture.
- Pulmonary hypertension – high blood pressure in the lung vasculature. This invariably causes right heart failure.
- Cor-pulmonale – Heart failure occurring as a result of a problem in the lungs.
- Researches have shown that lung cancer prevalence is high among the COPD patients
- Respiratory failure is almost inevitable unless properly treated
Prognosis/ life expectancy of COPD
COPD carries a bad prognosis if the diagnosis has happened at an advanced stage. It’s the 3rd leading cause of death in the United States. High body mass index, low FEV1 volume (a lung function test) less than 35%, profound difficulty in exertion markedly reduce the life expectancy of a COPD patient.
Treatment of COPD
Unfortunately, COPD is not a curable disease. However, the symptoms and the progression of the disease and the can be minimized with proper medical treatment.
The most important treatment of COPD is smoking cessation. Bronchodilators (drugs that dilate the airways) including short and long-acting β agonists, respiratory anticholinergics, xanthine derivatives can be used to relieve the difficulty in breathing during acute exacerbations. Steroids are indicated to prevent repeated exacerbations.
Pulmonary rehabilitations program is the mainstay of minimizing the disease progression. It includes risk factor reduction, family counseling, medical management, chest physiotherapy, physical therapy, and exercise.
Rarely surgical treatments are done to remove bullae inside the lungs.