Causes of Chronic Obstructive Pulmonary Disease


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Cause details for Chronic Obstructive Pulmonary Disease: When COPD develops, the walls of the small airways and alveoli lose their elasticity. The airway walls thicken, closing off some of the smaller air passages and narrowing larger ones. The passageways also become plugged with mucus. Air continues to get into alveoli when the lung expands during inhalation, but it is often unable to escape during exhalation because the air passages tend to collapse during exhalation, trapping the "stale" air in the lungs. These abnormalities create two serious problems which affect gas exchange:

  • Blood flow and air flow to the walls of the alveoli where gas exchange takes place are uneven or mismatched. In some alveoli there is adequate blood flow but little air, while in others there is a good supply of fresh air but not enough blood flow. When this occurs, fresh air cannot reach areas where there is good blood flow and oxygen cannot enter the bloodstream in normal quantities.

  • Pushing the air through narrowed obstructed airways becomes harder and harder. This tires the respiratory muscles so that they are unable to get enough air to the alveoli. The critical step for removing carbon dioxide from the blood is adequate alveolar airflow. If airflow to the alveoli is insufficient, carbon dioxide builds up in the blood and blood oxygen diminishes. Inadequate supply of fresh air to the alveoli is called hypoventilation. Breathing oxygen can often correct the blood oxygen levels, but this does not help remove carbon dioxide. When carbon dioxide accumulation becomes a severe problem, mechanical breathing machines called respirators, or ventilators, must be used.
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Pulmonary function studies of large groups of people show that lung function--the ability to move air into and out of the lungs--declines slowly with age even in healthy nonsmokers. Because healthy nonsmokers have excess lung capacity, this gradual loss of function does not lead to any symptoms. In smokers, however, lung function tends to worsen much more rapidly. If a smoker stops smoking before serious COPD develops, the rate at which lung function declines returns to almost normal. Unfortunately, because some lung damage cannot be reversed, pulmonary function is unlikely to return completely to normal. 1

Underlying condition causes of Chronic Obstructive Pulmonary Disease: The list of possible underlying conditions (see also Misdiagnosis of underlying causes of Chronic Obstructive Pulmonary Disease) mentioned in various sources as possible causes of Chronic Obstructive Pulmonary Disease includes:

  • Cigarette smoking

Chronic Obstructive Pulmonary Disease as a complication: Other conditions that might have Chronic Obstructive Pulmonary Disease as a complication might be potential underlying causes of Chronic Obstructive Pulmonary Disease. The list of conditions listing Chronic Obstructive Pulmonary Disease as a complication in our database includes:

Causes of Chronic Obstructive Pulmonary Disease: medical news summaries: The following medical news items are relevant to causes of Chronic Obstructive Pulmonary Disease:

Related information for causes of Chronic Obstructive Pulmonary Disease: Further relevant information on causes of Chronic Obstructive Pulmonary Disease may be found in the risk factors for Chronic Obstructive Pulmonary Disease and underlying causes of Chronic Obstructive Pulmonary Disease.

Footnotes:
1. excerpt from COPD: What Goes Wrong?: NHLBI

Last revision: May 26, 2003

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