An emphysema is a pulmonary disease in which the alveoli contains an excessive amount of air, which causes distention of the affected areas and cripples normal lung function. The air caught up in these tiny air sacs hinders the normal gas exchange (oxygen for carbon dioxide) that allow to oxygenate the blood. This abnormal expansion of the alveoli is usually irreversible and leads to the destruction of their epithelial walls.
If the emphysema spreads throughout the lung, it becomes inflated with bluish grey color. The symptons are difficulty in breathing, chronic fatigue, wheezing, loss of weight, etc. There are two types of emphysema: accute and chronic. Accute emphysema is caused by asphyxiation or drowning. Chronic emphysema is caused by smoking, pollution, aging, etc.