Chronic Obstructive Pulmonary Disease - COPD Overview

Chronic Obstructive Pulmonary Disease (COPD) is a progressive disorder of the lungs, which causes a long-lasting obstruction of the airways. It is also recognized by the names, chronic obstructive airway disease or chronic obstructive lung disease. Two common forms of COPD are chronic bronchitis and emphysema. These diseases cause a progressive, chronic obstruction of the airways in the lungs. Smoking accounts for about 90% cases of COPD. Chronic, persistent cough and shortness of breath are the major symptoms of COPD. COPD is the fourth-leading cause of death in the United States. About 14.2 million people are diagnosed with COPD in the United States.

Chronic Bronchitis: Chronic bronchitis causes swelling and inflammation of the lining of the airways and thickening of the bronchial walls. This can cause narrowing and obstruction of the airways. The production of mucous due to inflammation can lead to further obstruction of the airways. Approximately 12.5 million people are diagnosed with chronic bronchitis in the United States.

Emphysema: Emphysema causes a permanent, abnormal enlargement of the alveoli (air spaces) located at the end of terminal bronchioles (breathing passage of the lungs). The destruction of the alveolar walls can lead to reduction in the elasticity of the lungs. This causes obstruction of the airflow out of alveoli, which interferes with the exchange of gases within the lungs. About 1.7 million people suffer from emphysema in the United States.

People with COPD can also suffer from chronic asthma and bronchiectasis. Asthma is caused by obstruction of airflow due to inflammation of the airways and muscle spasm surrounding the airways (bronchospasm). In bronchiectasis, there may be repeated, serious lung infections and permanent damage to the airways.

Causes of COPD

Cigarette smoking is the leading cause of Chronic Obstructive Pulmonary Disease. Not all, but about 15% of smokers suffer from COPD. Smokers with COPD are more likely to have deterioration in the lung function and frequent respiratory symptoms than the nonsmokers with COPD. Environmental tobacco smoke or second-hand smoke can also contribute in developing the respiratory infections, leading to reduced lung function. Chronic bronchitis is triggered by infection, allergies and air pollution. A deficiency of protein namely alpha-1 antitrypsin can increase the risk of emphysema in the nonsmokers.

Cigarette smoking and exposure to tobacco are the major risk factors for COPD. Cigarette smoke causes irritating effects on the cells of the lungs, leading to inflammation. Smoke stimulates these cells to release an enzyme elastase that causes breakdown of elastic fibers in the lung tissues. A family history of COPD and long-term exposure to lung irritants like air pollution, dust and chemical fumes are some other risk factors for COPD.

Symptoms of COPD

People, after frequent smoking for more than 20 years, develop the symptoms of COPD such as chronic cough, frequent respiratory infections and shortness of breath (dyspnea). In emphysema, shortness of breath is the main symptom. Generally, it is experienced with increased physical activities. But as emphysema progresses, dyspnea can also occur at rest. Chronic bronchitis or bronchiectasis causes the symptoms like chronic cough and sputum production. There is higher risk of chest infections, which can cause coughing, dyspnea, fever, wheezing and production of discolored, cloudy sputum. Some other symptoms of COPD are fatigue, depression, confusion, memory loss and decreased exercise tolerance.

In the advanced stage of COPD, there may be cyanosis (a bluish discoloration of lips and nail beds) due to deficiency of oxygen in the blood. Patient may also suffer from morning headaches, weight loss and anorexia. In advanced COPD, the blood flow through the lungs is blocked, which can cause pulmonary hypertension (increased pressure in the blood vessels of the lungs). There is also a risk of Cor pulmonale (right heart failure), leading to swelling of the ankles and feet. Due to damage to the inner lining and blood vessels of the airways, patient may cough up blood, known as hemoptysis. This could be indicative of development of lung cancer.

Diagnosis of COPD

COPD is diagnosed on the basis of findings of physical examination and medical history of the patient as well as various tests and laboratory investigations. Certain tests such as X-ray, CT scan or MRI scan of the chest, pulmonary function test (PFT) as well as some laboratory investigations are performed to confirm the diagnosis. Chest X-ray and CT scan can help to rule out the possibility of lung infections like pneumonia and lung cancer. The laboratory investigations include determination of arterial blood gases (ABG) and sputum analysis.

Treatment for COPD

The treatment for COPD is aimed at relieving the symptoms and exacerbations, preventing further deterioration in lung function, preserving normal lung function and improving performance of daily activities and quality of life. People diagnosed with COPD should immediately quit smoking. If smoking is continued, then it can cause more rapid loss of lung function. Since nicotine present in a cigarette is addictive, cessation of smoking can give rise to symptoms like anger, irritability, fatigue, depression, anxiety, difficulty in concentration and extreme cravings for cigarettes. Nicotine replacement therapies are helpful to relieve these nicotine withdrawal symptoms. Nicotine chewing gum and nicotine skin patches can effectively help to decrease cigarette cravings. Use of antidepressants like bupropion or oral corticosteroids is also beneficial.

The airways obstruction in COPD can be treated with bronchodilators. These medications help to relax the muscles surrounding the airways and thus in turn, open the airways. Bronchodilators can be taken orally, inhaled or administered intravenously. Beta-2 agonists like albuterol, levalbuterol, isoetharine and metaproterenol also show the bronchodilating effects. Use of aerosolized anticholinergic agents like ipratropium bromide is effective in relieving the symptoms such as shortness of breath. Some long-lasting bronchodilators such as methylxanthines (theophylline and aminophylline) act by opening the breathing passages, reducing inflammation, improving respiratory muscle function and stimulating the brain respiratory center.

Corticosteroids like triamcinolone acetonide, fluticasone, budesonide and beclomethasone dipropionate are the anti-inflammatory medications, which can help to reduce inflammation of the airways that causes airflow obstruction. In people with COPD, chronic infection of the airways is very common. Therefore, antibiotic therapy including amoxicillin, cefaclor, clarithromycin, azithromycin, or trimethoprim/sulfamethoxazole is administered in order to treat acute exacerbations.

COPD generally interferes with the oxygenation of the blood (hypoxemia). Therefore, oxygen therapy including supplemental oxygen is helpful for people with COPD. Emphysema may result from severe alpha-1 antitrypsin deficiency (AAT). It can be treated with replacement of active AAT by injection.

Certain surgical options such as bullectomy and lung volume reduction surgery are effective in improving the symptoms and restoring the lung function in people with emphysema. Lung transplantation is the latest surgical option used to treat the advanced lung disease.

The only way to prevent this hazardous lung disorder is to quit smoking. Since smoking is the root cause of a number of health problems, stopping smoking is beneficial for good overall health. You should stay away from stress, avoid exposure to smoke, allergens and air pollutants, which are the triggering factors for COPD.