The difference between chronic obstructive pulmonary disease (COPD) and emphysema is that COPD is an umbrella term that denotes a collection of chronic respiratory illnesses, which includes emphysema, along with other conditions, like chronic bronchitis and asthma. In this respect, the difference in the two lies primarily in definition and mortality rate. COPD patients are dealing with a myriad of diseases and, therefore, have a higher mortality rate than those who suffer solely from emphysema. To be diagnosed with either COPD or emphysema, a patient’s lungs must be damaged permanently, preventing adequate oxygen from being circulated throughout the body.
The most prominent symptom of COPD and emphysema is the inability of the lungs to exhale properly. If the disability is caused solely by damage to the alveolar sacs within the lungs, the patient is most times given the diagnosis of emphysema. If, on the other hand, this symptom is aggravated by bronchitis, which is an irritation of the bronchioles, or asthma, a COPD diagnosis is usually given. Both COPD and emphysema are most often caused by first-hand inhalation of tobacco smoke, although some bullous lung diseases, cystic fibrosis, and alpha-1 antitrypsin deficiencies have been implicated in both conditions as well. Individuals who have chronic asthma, especially since childhood, are often at higher risk for developing emphysema and then COPD if they smoke tobacco.
The first sign of both COPD and emphysema is an extreme shortness of breath after exertion. This symptom becomes worse and more pronounced as the disease progresses until the patient becomes short of breath even at rest. Chronic bronchitis, another prerequisite for a COPD diagnosis, is diagnosed when a chronic cough, excess mucus production, and sometimes, cyanosis — a bluish tint to the skin — are present. Gradual loss of lung function, as characterized by these general symptoms, is the diagnostic criteria upon which a COPD diagnosis is made. If a close family member has the disease, a diagnosis may be made sooner because research points to a probable genetic link to the aforementioned respiratory illnesses as well.
COPD and emphysema can each be quantified with laboratory testing. The most common test is a lung function test, called spirometry. The test is done by blowing into a machine that can determine specific lung capacity. This non-invasive test is usually the first course of action when a respiratory pathogenesis is suspected. To make a definitive diagnosis, the physician may do X-rays or other scans of the lungs to look for damaged tissue.