View source for Emphysema overview

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{{Emphysema}}
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==Overview==
'''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]].

The term ''emphysema'' means "''swelling''" and derives from the [[Greek language|Greek]] {{lang|el|ἐμφυσᾶν}} ''emphysan'' meaning "''inflate''" - itself composed of ἐν ''en'', meaning "''in''", and φυσᾶν ''physan'', meaning "''breath, blast''".<ref>[http://dictionary.reference.com/browse/emphysema emphysema] at [[dictionary.com]]</ref>
{{#widget:priyapicture|src=http://upload.wikimedia.org/wikipedia/commons/9/9a/Barrowchest.JPG|alt=A lateral chest x-ray of a person with emphysema. Note the barrel chest and flat diaphragm.|width=300|height=300}}
==Historical perspective==
The terms chronic bronchitis and emphysema were formally defined at the CIBA guest symposium of physicians in 1959. COPD has probably always existed but has been called by different names in the past. Bonet described a condition of  “voluminous lungs” in 1679. Matthew Baillie illustrated an emphysematous lung in 1789 and described the destructive character of the condition.  The term COPD was first used by William Briscoe in 1965 and has gradually overtaken other terms to become established today as the preferred name for this disease.
==Pathophysiology==
Emphysema is caused by loss of elasticity of the lung tissue, from  destruction of structures supporting the [[alveoli]], and destruction of capillaries feeding the alveoli. The result is that the  ''small airways'' collapse during exhalation, leading to an obstructive form of lung disease (airflow is impeded and air is generally "trapped" in the lungs in [[COPD|obstructive lung diseases]]). When toxins such as smoke are breathed into the lungs, the particles are trapped and cause a localized [[inflammation|inflammatory]] response. Chemicals released during the inflammatory response (e.g., elastase) can break down the walls of alveoli (alveolar septum). This leads to fewer but larger alveoli, with a decreased surface area and a decreased ability to absorb oxygen and exude carbon dioxide by diffusion. The activity of another molecule called alpha 1-antitrypsin normally neutralizes the destructive action of one of these damaging molecules.
==Risk Factors==
Chronic obstructive pulmonary disease is a group of [[disease|diseases]] characterized by the pathological limitation of airflow in the [[airway]] that is not fully reversible. A full comprehensive diagnosis is needed to eliminate related conditions and isolate the influence of lifestyle and behavior risk factors on condition outcome. Some common risk factors are cigarette smoking, occupational pollutants, air pollution and genetics. Other risk factors are increasing age, male gender, allergy, repeated airway infection.

==Differential Diagnosis==
In clinical practice, COPD is defined by its characteristically low airflow on [[lung function test]]s.<ref name=Nathell>{{cite doi|10.1186/1465-9921-8-89}} [http://respiratory-research.com/content/8/1/89]</ref> In contrast to [[asthma]], this limitation is poorly reversible and usually gets progressively worse over time. It should be differentiated from certain conditions that have similar presentation for instance [[congestive heart failure]], [[chronic asthma]], [[bronchiectasis]], and [[bronchiolitis obliterans]].

==References==
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[[Category:Pediatrics]]
[[Category:Gastroenterology]]
[[Category:Genetic disorders]]
[[Category:Rare diseases]]
[[Category:Hepatology]]
[[Category:Mature chapter]]

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