Emphysema is a lung disease marked by the gradual destruction of tiny sacs in the lungs, called alveoli, which introduce oxygen into the bloodstream and remove the blood-borne waste gas carbon dioxide. In its main form, it belongs to a larger grouping of lung diseases, known collectively as chronic pulmonary obstructive disease, or COPD. People who smoke “crack” cocaine can significantly elevate their risks for a form of emphysema called bullous emphysema, which occurs when multiple alveoli collapse and form larger sacs, known as bullae, that don’t contribute to proper oxygen/carbon dioxide exchange within the lungs.
Lung Function Basics
Each lung contains an extensive series of branching pathways that starts with a main line called the primary or main stem bronchus, continues onward into smaller openings called bronchioles, and ends at the alveoli. There are literally hundreds of millions of alveoli in each lung, clustered in bunches near the end of each individual bronchiole. When you breathe in, oxygen (and everything else contained in the immediate airborne environment) makes its way down the lungs’ pathways to the alveoli; once inside the alveoli, it passes through these sacs’ permeable wall structures and filters into the bloodstream through capillaries, which are very fine-gauged blood vessels embedded in the lungs’ tissues. When you breathe out, carbon dioxide waste inside these same blood vessels enters the alveoli, passes through the lungs and exits the body.
Emphysema does two basic things. First, it enlarges, distorts and eventually destroys the walls of large numbers of alveoli; in turn, destruction of the alveoli reduces the amount of oxygen the lungs can transfer into the bloodstream. Emphysema also damages the tips of the bronchioles in such a way that these passages close shut when an affected individual breathes out. This means that any air that comes in through the bronchioles and makes it to the damaged alveoli has no clear pathway to exit back out of the lungs. In addition, both alveoli destruction and bronchiole damage make it difficult (or in some cases, impossible) for carbon dioxide waste to escape the body.
The most common cause of emphysema is chronic exposure to some sort of substance that irritates the lung interiors. In addition to crack cocaine, substances that can produce this kind of irritation include cigarette smoke or any other form of tobacco smoke, and any form of significant air pollution, including fumes from industrial processes and dust produced by the mining of coal or other rocks or minerals. Some people also develop emphysema because they have a genetic deficiency of a specific internal protein required to keep the lungs’ structures in proper working order.
The lack of oxygen and buildup of carbon dioxide associated with advancing emphysema can produce or contribute to serious health complications that include lung collapse (pneumothorax), pneumonia, dangerous heartbeat irregularities, heart failure, clinical malnutrition, and osteoporosis. It can also produce respiratory failure, a condition that results from poor oxygen transfer into the bloodstream, poor carbon dioxide transfer out of the bloodstream, or a combination of both of these problems.
Crack Cocaine’s Effects
People who smoke crack cocaine can develop both baseline emphysema and the emphysema complication known as bullous emphysema, according to the authors of a multi-university study review published in 2007 by the Radiological Society of North America. In people with bullous emphysema, the collapse of individual alveoli leads to the formation of bullae (singular, bullus), which are larger pockets of enclosed space. These bullae don’t link effectively to any bronchioles and don’t have the capacity to transfer oxygen into the bloodstream or remove carbon dioxide waste. In addition, they can take up large amounts of the lungs’ interiors and seriously restrict the amount of space that can be used during normal lung expansion.
Some forms of bullous emphysema develop so extensively that they can effectively obliterate proper function in 50 percent of an affected lung, the Mayo Clinic explains. However, crack smokers tend to develop a more limited form of the complication that usually only affects the outer portion of each lung’s upper lobe. This means that bullous emphysema frequently leaves enough lung function for crack smokers to avoid a fatal emphysema-related outcome for relatively extended periods of time. In the interim, many crack smokers die from other causes.
No one knows exactly what aspect of crack use triggers the onset of emphysema, the authors of the study published by the Radiological Society of North American explain. However, in all likelihood, contributing factors include the toxic effects of the cocaine content in crack smoke, the toxic effects of other substances contained in crack smoke, and the toxic effects of cigarette smoking in crack users.