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| {{Emphysema}}
| | #REDIRECT [[Chronic obstructive pulmonary disease historical perspective]] |
| {{CMG}}
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| ==Overview==
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| '''Emphysema''' is a long-term, progressive disease of the [[lung|lungs]] that primarily causes shortness of breath. In people with emphysema, the [[tissue|tissues]] necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called [[chronic obstructive pulmonary disease]] or COPD (pulmonary refers to the lungs). Emphysema is called an obstructive lung disease because the destruction of lung tissue around smaller sacs, called [[alveoli]], makes these air sacs unable to hold their functional shape upon [[exhalation]]. Emphysema is most often caused by [[tobacco]] [[smoking]] and long-term exposure to [[air pollution]].
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| ==Causes==
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| The majority of all emphysema cases are caused by [[Health effects of tobacco|smoking tobacco]]. Emphysema cases that are caused by other [[etiology|etiologies]] are referred to as ''secondary'' emphysema. {{Citation needed|date=October 2011}}
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| In rare cases, emphysema develops due to a [[gene|genetic]] [[mutation]] that leads to [[alpha 1-antitrypsin deficiency]]. Severe cases of A1AD may also develop [[cirrhosis]] of the [[liver]], where the accumulated A1AT leads to a [[fibrosis|fibrotic]] reaction that produces scarring and dysfunction; longstanding cirrosis may eventually produce liver [[cancer]] ([[hepatocellular carcinoma]].
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| Some types of emphysema occur as a normal part of aging, and are particularly common found in the oldest old (85 years of age and older). At about 20 years of age, [[Homo sapiens|humans]] stop developing new alveolar tissue. In the years following the cessation of development of new alveoli, lung tissue starts to deteriorate (on a "net" basis) at a relatively slow rate. This deterioration of lung capacity and function is a normal and natural part of aging in healthy people. As alveoli die, the number of lung [[capillaries]] decrease, and the [[elastin]] of the lungs begins to break down, causing a loss of pulmonary elasticity. As people age, they also tend to lose strength and mass in their chest muscles, which weaken. [[Bone|bones]] and [[cartilage]] start to deteriorate, and posture changes. Together, all of these age-related changes in [[respiratory system]] structures can cause or contribute to the development of emphysema. Though not all elderly people will develop clinically evident emphysema, they are all at risk of decreasing respiratory function, which limits maximum performance and produces discomfort at higher levels of exertion.
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| Anything that causes the body to be unable to inhibit [[proteolytic enzymes]] occurring naturally in the lung can cause, or contribute to, the development of emphysema. This could include exposure to air pollution, second-hand smoke, and/or other chemicals and toxins. {{Citation needed|date=October 2011}}
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| ==References==
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| {{reflist|2}}
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| [[Category:Pediatrics]]
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| [[Category:Gastroenterology]]
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| [[Category:Genetic disorders]]
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| [[Category:Rare diseases]]
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| [[Category:Hepatology]]
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| [[Category:Mature chapter]]
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| {{WH}}
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| {{WS}}
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