Most common type of emphysema is: March 2013

Ans. A i.e. Centriacinar Emphysema It is COPD. It is defined pathologically as an abnormal permanent enlargement of air spaces distal to the terminal bronchioles, accompanied by the destruction of alveolar walls and without obvious fibrosis. It frequently occurs in association with chronic bronchitis. Patients have been classified as having COPD with either emphysema or chronic bronchitis predominance. The 3 described morphological types of emphysema are centriacinar, panacinar, and paraseptal. Centriacinar emphysema begins in the respiratory bronchioles and spreads peripherally. Also termed centrilobular emphysema, this form is associated with long-standing cigarette smoking and predominantly involves the upper half of the lungs. - Panacinar emphysema destroys the entire alveolus uniformly and is predominant in the lower half of the lungs. Panacinar emphysema generally is observed in patients with homozygous alfal antitrypsin deficiency. In people who smoke, focal panacinar emphysema at the lung bases may accompany centriacinar emphysema. - Paraseptal emphysema, also known as distal acinar emphysema, preferentially involves the distal airway structures, alveolar ducts, and alveolar sacs. The process is localized around the septae of the lungs or pleura. Although airflow frequently is preserved, the apical bullae may lead to spontaneous pneumothorax. Giant bullae occasionally cause severe compression of adjacent lung tissue.