Emphysema classification
Classification
Emphysema can be classified into primary and secondary types. However, it is more commonly classified by location into panacinary and centroacinary (or panacinar and centriacinar,[1] or centrilobular and panlobular).[2]
- Panacinar (or panlobular) emphysema: The entire respiratory acinus, from respiratory bronchiole to alveoli, is expanded. Occurs more commonly in the lower lobes (especially basal segments) and in the anterior margins of the lungs.[1]
- Centriacinar (or centrilobular) emphysema: The respiratory bronchiole (proximal and central part of the acinus) is expanded. The distal acinus or alveoli are unchanged. Occurs more commonly in the upper lobes.[1]
Other types include distal acinar emphysema and irregular emphysema.[1] A special type is congenital lobar emphysema (or CLE).
Congenital lobar emphysema
CLE results in overexpansion of a pulmonary lobe, and resultant compression of the remaining lobes of the ipsilateral lung (and possibly also the contralateral lung). There is bronchial narrowing because of weakened or absent bronchial cartilage.[3] There may be congenital extrinsic compression, commonly by an abnormally large pulmonary artery. This causes malformation of bronchial cartilage, making them soft and collapsible.[3] CLE is a potentially reversible (yet possibly life-threatening) cause of respiratory distress in the neonate.[3]
Paraseptal emphysema
Paraseptal emphysema is a type of emphysema which involves the alveolar ducts and sacs at the lung periphery. The emphysematous areas are subpleural in location and often surrounded by interlobular septa (hence the name). It may be an incidental finding in young adults, and may be associated with spontaneous pneumothorax. It may also be seen in older patients with centrilobular emphysema. Both centrilobular and paraseptal emphysema may progress to bullous emphysema. A bulla is defined as being at least 1 cm in diameter, and with a wall less than 1mm thick. Bullae are thought to arise by air trapping in emphysematous spaces, causing local expansion.[4]
- ↑ 1.0 1.1 1.2 1.3 "Emphysema". Retrieved 2008-11-20.
- ↑ Anderson AE, Foraker AG (1973). "Centrilobular emphysema and panlobular emphysema: two different diseases". Thorax. 28 (5): 547–50. doi:10.1136/thx.28.5.547. PMC 470076. PMID 4784376. Unknown parameter
|month=ignored (help) - ↑ 3.0 3.1 3.2 eMedicine Specialties > Radiology > Pediatrics --> Congenital Lobar Emphysema Author: Beverly P Wood, MD, MS, PhD, University of Southern California. Updated: December 1, 2008
- ↑ Webb WR, Higgins CB. Thoracic Imaging. Lippincott, Williams & Wilkins 2005.