The Macklin effect: pulmonary interstitial emphysema and pneumomediastinum
The Macklin effect describes one of the pathophysiological processes of pneumomediastinum in blunt chest trauma. The Macklin effect accounts for ~40% of severe blunt traumatic pneumomediastinum. Exclusion of tracheobronchial and oesophageal causes of pneumomediastinum is mandatory to exclude concomitant injury 1.
The proposed mechanism is alveolar rupture with air dissecting along peribronchovascular interstitial sheaths, interlobular septa, visceral pleura and into the mediastinum 1.
Pulmonary interstitial emphysema with air tracking along the bronchovascular sheaths towards the hilum and associated pneumomediastinum.
History and etymology
The pathophysiologic process was first proposed by C C Macklin in 1939 2.
- 1. Wintermark M, Schnyder P. The Macklin effect: a frequent etiology for pneumomediastinum in severe blunt chest trauma. Chest. 2001;120 (2): 543-7. Chest (citation) - Pubmed citation
- 2. Macklin CC. Transport of air along sheaths of pulmonic blood vessels from alveoli to mediastinum: clinical implications. Arch Intern Med 1939; 64:913–926
- 3. Murayama S, Gibo S. Spontaneous pneumomediastinum and Macklin effect: Overview and appearance on computed tomography. World J Radiol. 2014;6 (11): 850-4. Free text at pubmed - Pubmed citation