Emphysema: what you need to know
What is emphysema?
Emphysema is a chronic (ongoing) condition in which the walls of the alveoli in the lungs become gradually damaged, resulting in irreversible destruction of the tissues of the lower lungs.
The alveoli are the air sacs at the end of the smallest branches of the airways of the lungs. When you breathe in, air is sucked down through the branches of the lungs (the bronchi and bronchioles), eventually reaching the alveoli, where oxygen is transferred to the bloodstream and carbon dioxide is removed from the bloodstream.
What happens to the lungs in emphysema?
In emphysema, the walls of the alveoli are damaged. This makes it harder for them to prop open the tiny microscopic branches of the lungs called bronchioles, so when air is breathed out of the lungs the bronchioles collapse. As the damage to the alveoli progresses over time, the lungs become less elastic and less able to transfer oxygen to the bloodstream. This results in the affected person experiencing breathlessness and breathing difficulties, especially on exertion, but even at rest in severe disease.
Emphysema and chronic bronchitis, particularly if these 2 conditions occur together, cause long-term obstruction of the airways, and are often called chronic obstructive pulmonary disease (COPD).
What causes emphysema?
Emphysema doesn’t come on suddenly, but gradually, often developing over many years. The single most preventable cause of emphysema is cigarette smoking, with a very high percentage of people with the condition being smokers.
Exposure to industrial pollutants in the air may also be a contributing factor.
A1AD-related emphysema
There is also a rare type of emphysema known as A1AD-related emphysema, a genetic condition in which a person’s body lacks a protein called alpha1-antitrypsin (AAT). AAT protects the lungs from excessive exposure to an enzyme known as neutrophil elastase, which helps fight bacteria but which can damage the lungs if not neutralised by AAT. Smoking hastens the speed at which emphysema develops in people with alpha1-antitrypsin deficiency.
Symptoms
The most common symptom of emphysema is shortness of breath, which often occurs after only mild exertion. Cough is another symptom. In the severe stages the chest may become ‘barrel-shaped’ and the shortness of breath may be disabling and lead to a drastic restriction of daily activities.
Last Reviewed: 29 July 2009
