Macklin effect (pulmonary interstitial emphysema and pneumomediastinum)
Esophageal
emergencies: another important cause of acute chest pain. Pneumomediastinum. Thirty-four-year-old male with chest pain after vigorous cough. Axial CT image shows moderate pneumomediastinum (long arrow) caused by Macklin effect. Subpleural gas (short arrow) caused by alveolar rupture in the setting of increased intrathoracic pressure with air dissecting along the subpleural interstitium, interlobular septa, peribronchovascular interstitial sheaths, and eventually into the mediastinum (Macklin effect). While this mimics EP, there is a lack of inflammatory changes and hydropneumothorax commonly associated with esophageal perforation
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 esophageal causes of pneumomediastinum is mandatory to exclude concomitant injury.
Pathology
The proposed mechanism is an alveolar rupture with air dissecting along peribronchovascular interstitial sheaths, interlobular septa, and the visceral pleura into the mediastinum .
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 .
