The Macklin effect describes one of the pathophysiological processes of pneumothorax and pneumomediastinum in blunt chest trauma. This effect accounts for the formation of ~40% of severe blunt traumatic pneumomediastinum. Exclusion of tracheobronchial and esophageal causes of pneumomediastinum is mandatory to exclude concomitant injury.
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Pathology
The mechanism proposed by Macklin was alveolar rupture with air dissecting along peribronchovascular interstitial sheaths, interlobular septa, and the visceral pleura into the mediastinum 1.
Radiographic features
CT
Pulmonary interstitial emphysema with air tracking along the peribronchovascular sheaths towards the hilum and associated pneumomediastinum.
History and etymology
The pathophysiologic process was first proposed by C C Macklin in 1939 2.