CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) & EMPHYSEMA

What Is COPD? COPD is a disease of the lungs involving progressive destruction of the small airways and reduced airflow and gas exchange. Generally, COPD is due to one of two disease processes; either emphysema or chronic bronchitis, although the two coexist to varying degrees in most patients. Both lead to obstructive lung disease by causing scarring and distortion of lung tissue, loss of alveoli (the small air pockets where oxygen-carbon dioxide exchange occurs), overproduction of mucus and tightening of muscle in the airways. Emphysema is characterized by over-inflation of the small airways and destruction of the alveoli, giving the lungs the appearance of Swiss cheese. Chronic bronchitis is a disease of excess secretion of mucus and of airway hyper-sensitivity; that is, the airways are too easily stimulated to contract and thus reduce airflow. Some cases of COPD are due to chronic asthma. COPD is among the leading causes of death in North America.

What Causes COPD? Risk factors for the development of obstructive lung disease include occupational pollutants and a rare inherited condition (alpha-1 antitrypsin deficiency), but by far the most important is cigarette smoking. Although the majority of COPD patients are smokers, only 10 to 15% of smokers will develop COPD, indicating that other unknown factors must also play a role.

What Are The Signs And Symptoms Of COPD? The most important symptoms of COPD are increased production of mucus and shortness of breath. Patients with chronic bronchitis, in particular, bring up large amounts of white-coloured mucus, especially upon waking in the morning. Shortness of breath is first apparent upon exertion: walking up stairs, uphill, or moving quickly. As the disease progresses, less physical effort is tolerated before difficulty breathing occurs. Patients with COPD are likely to have a chronic cough, shallow, rapid breathing, and to wheeze (make whistling noises while breathing). Some patients become thin and wasted-looking, while others appear overweight and bloated. Some patients have bluish skin, especially noticeable in the lips and fingertips, while others have reddish faces, as though they have just been jogging.

With What Might COPD Be Confused? Shortness of breath is a symptom common to both respiratory and cardiac illnesses; however, given the long-term progression of COPD, it is unlikely that COPD would be misdiagnosed if the patient's history of respiratory illness (and smoking) is known. Tests that are commonly performed to assist in the diagnosis of COPD include chest X-rays, primarily to exclude other conditions, and studies of lung (pulmonary) function. In some cases measurements of blood gases may also be performed.

What Is The Treatment For COPD? The goals of treatment of a patient with stable COPD are threefold; to prevent further deterioration of the lungs, to relieve symptoms, and to prevent complications. The best means of halting lung damage is to stop smoking; in fact, this is the only "therapy" that will increase life expectancy. Other lifestyle factors such as diet and exercise should also be assessed and modified if necessary. Patients with COPD should receive vaccines against common respiratory infectious agents (e.g. the influenza virus and the bacteria Streptococcus pneumoniae and Hemophilus influenzae), as recurrent infection is a major problem in patients whose lung function is already compromised. To ease the effort of breathing, inhaled bronchodilators are prescribed; although these drugs provide symptomatic relief by temporarily opening the airways, they do not improve lung function. The first class of bronchodilators used in COPD are known as anticholinergic drugs, which prevent the contraction of muscle in the airways. Should these be ineffective, drugs called beta-agonists are prescribed; these are the inhalers used by asthmatics. Theophylline is a third drug prescribed to make breathing easier: it is a chemical related to caffeine, and works by increasing the strength of the diaphragm (an important muscle for breathing located beneath the lungs). It is generally less effective than the bronchodilators, and is more likely to have side effects. Some patients may receive a course of oral corticosteroids, which act to reduce inflammation in the lungs. If a bacterial infection occurs, administration of an appropriate will be required. In very seriously ill patients, oxygen delivered by nasal prongs or a mask may be necessary. Patients with COPD should consult a physician if air travel is contemplated. Surgery plays a relatively minor role in the treatment of this condition. One procedure that is under study is lung volume reduction surgery, in which an area of lung severely affected by over-inflation (see above) is removed. In very severe cases, a single lung transplant may be required; this is technically a much easier procedure to perform than is a double lung transplant.

What Are The Complications Of COPD? Periodically, patients with COPD are likely to suffer "acute exacerbations" or periods of worsening disease typified by extreme shortness of breath, poorer exercise tolerance, and/or increased cough and production of mucus. Exacerbations are generally caused by respiratory infection, either viral or bacterial. Often, patients can be treated on an outpatient basis, but occasionally hospitalization is required. Due to compromised lung function, patients with COPD are more likely to suffer serious respiratory consequences, and even respiratory failure if they contract other illnesses that affect the lungs, such as pneumonia, congestive heart failure or pulmonary embolism. All of these conditions, like COPD itself, are more common in smokers.