Emphysema is a chronic lung condition in which the lungs' natural airspaces, called alveoli, become larger but decrease in number. The tissue surrounding the alveoli loses elasticity so that the airspaces can no longer expand and shrink as usual. This reduces the amount of oxygen transferred by the lungs to the bloodstream, making it more difficult for you to breathe.
Emphysema usually results from exposure to toxins like cigarettes as well as air pollution, dust, chemical fumes, and irritants. Older adults are more likely to be affected and many people who have emphysema are not aware that they have it.
Cigarette smoking is the number one cause of emphysema. Although smoking has decreased in North America since 1964, it's still a major concern among young people. 1 in 5 people who have smoked a pack of cigarettes a day for 20 years have lung disease, and 5 out of every 6 lung cancer victims are smokers. A huge majority of emphysema sufferers have smoked heavily in the past. A burning cigarette emits over 4,000 different chemicals, many of which are carcinogenic (cancer-causing) or otherwise toxic to living tissue.
Infections of the respiratory tract can also destroy lung tissue and thus contribute to the development or worsening of emphysema. Likewise, having emphysema increases the likelihood of infection.
Heredity is occasionally a factor in emphysema. Carriers of a specific genetic abnormality called homozygous alpha-1-antitrypsin deficiency are at high risk of developing emphysema. However, it is relatively rare and accounts for less than 1% of cases. If you have alpha-1-antitrypsin deficiency, it's vital not to smoke.
Aging naturally brings changes to the lungs and air sacs even in non-smokers. The loss of elasticity can eventually become severe enough to be classified as emphysema. Air pollution can also irritate the lungs and cause emphysema, although pollution alone is rarely the cause.
There may be few symptoms at the beginning of the disease. As the air sacs become damaged, shortness of breath with physical activity is usually the first symptom. As emphysema progresses, you may experience shortness of breath even when you're resting. This can make normal activities such as eating difficult, which can lead to a reduced appetite and weight loss. Other symptoms include chest tightness, fatigue, and chronic cough.
As the air sacs become more stretched, air gets trapped in pockets called bullae that form in the lungs. This can produce a characteristic "barrel chest," which is the shape of the hyper-expanded chest.
Chronic lung damage prevents the heart from circulating blood normally. Lung damage can cause pressure elevations in the part of the heart that moves blood through the lungs. This is called pulmonary hypertension and is suspected when people with emphysema develop leg swelling, abdominal bloating, or prominent pulsations in the veins in the neck.
Bullae can rupture outside the lung into the pleural space (the space that surrounds the lung). As the air accumulates outside the lung, it may result in a life-threatening condition called pneumothorax. The body will also attempt to compensate for the low oxygen level by increasing the number of red blood cells (secondary polycythemia). Sometimes, the increase in red blood cells can be so severe that it causes blood clots.