Take my breath away: Emphysema basics
Column by Dr. Tim Moser
Martin was having a hard time catching his breath. He was standing on the landing of a flight of stairs. Shortness of breath had caused him to stop before he had climbed a single floor. His labored breathing was accompanied by a fast heart rate. As he slowly regained his breath, Martin instinctively felt for his pack of cigarettes in his breast pocket. Forty years of smoking had taken a toll on his body, but all attempts to quit in the past had been unsuccessful. Climbing the remaining stairs seemed as daunting as scaling a high mountain peak. With deliberation, Martin grasped the hand rail and started once again.
Emphysema (also known as COPD) is a common lung condition which is most often associated with smoking tobacco. Over time, the condition often worsens, rendering the lungs less efficient. Many patients with emphysema become dependent on supplemental oxygen to meet their body’s needs.
Normal lung function
Healthy lungs are the site in the body where oxygen is taken into the bloodstream, and waste products (mainly carbon dioxide) are expelled from the body. To accomplish this task, the lungs are equipped with an immense internal surface area, which measures about the area of a tennis court! The lungs also have a wealthy supply of blood from the heart. In fact, half of the blood pumped by the heart passes through the lungs to be replenished with oxygen, before being sent out of the body to nourish the cells of the body.
All about alveoli
The gas exchange that occurs in the lungs is completely dependent on a small structure called alveoli. Alveoli are small air sacks that branch off the smallest of airways in the longs. Alveoli are similar in appearance to a cluster of grapes, with the grape stems representing airways, and hollow grapes representing the alveoli. An average adult has about 300 million alveoli total, if the lungs are healthy.
A ghost in the machine
As the alveoli become damaged, there is a gradual loss of lung function, and a decreased ability for the body to supply the needed oxygen to the bloodstream. The most common cause of lung damage is tobacco use. Tobacco targets the very heart of the lung by damaging the alveoli. Let’s go back to the example of a cluster of grapes. With the persistent exposure to tobacco smoke, the alveoli start to combine together with their neighbors, making for larger and larger air spaces. Each time an alveoli merges with another, critical surface area is lost. Over time, the lung develops large air pockets that cannot allow the transport of oxygen efficiently. Soon the lung develops a ‘honeycomb’ appearance on cross section, with a substantial decrease in the number of alveoli.
The airways delivering air to the alveoli also are affected in emphysema. The air passages become limp and flabby, and can collapse easily, blocking airflow out of the lungs. The result is poor lung function, ‘air trapping’ in the lungs, and symptoms of shortness of breath.
Symptoms of emphysema
As the lung damage progresses, worsening shortness of breath becomes apparent. At first, this is most noticeable with exercise. Over time, even low intensity exercise leads to shortness of breath, such as walking around inside the home. To compensate for the lack of oxygen in the blood, the rate of breathing increases. Because air is being trapped in the lungs by the small airways that collapse easily, the chest expands in diameter. A deep cough is also common, especially in the early morning hours. Lung infections can become frequent.
Since most cases of emphysema are caused by smoking, the cornerstone of therapy is to stop smoking. Unless the emphysema is very far advanced, stopping the use of tobacco can have significant positive effects on lung function over the years to come. Many patients respond well to inhaled medications that help keep air passages open, and allow for better movement of air. These medications are used several times per day in most cases.
Oral medications, such as Prednisone are sometimes used, especially when the emphysema flares up. A short course of antibiotics is often prescribed to treat any underlying infection.
Oxygen therapy is the only treatment that has been shown to increase the survival in patients with severe emphysema. Use of continuous oxygen usually increases alertness, and may improve muscle strength.
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