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College of Medicine: Department of Radiology

Pneumothorax, Pneumomediastinum – Air Leaks In The ICU

Last modified: October 8, 2022
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Most newborns (commonly preterms) needing additional respiratory support are placed on mechanical ventilation in the intensive care unit, which increases the risk of air dissecting through the alveolar spaces into the pulmonary interstitium with eventual rupture of air into the pleural cavity (4, 6).Useful signs in the diagnosis of small pneumothoraces include the deep sulcus sign (sharp and lucent costophrenic angle on the supine radiograph), medial stripe sign (increased lucency at the interface of the mediastinum and medial lung in case of a medial pneumothorax) and a hyperlucent hemithorax (4).

Axial CT Chest (non contrast) - small pneumothorax
Axial non-contrast chest CT through the lung apices demonstrates a small right apical pneumothorax with bubbly appearance of the anterior mediastinum reflecting pneumomediastinum.

Pneumomediastinum can also accompany pneumothorax as a complication of positive pressure ventilation and manifests as accumulation of air in the mediastinum pushing the normal thymus upward and laterally (5, 6) which results in the characteristic angel wing sign.

Chest X-ray - Continuous Diaphragm Sign
Frontal chest radiograph of this infant’s chest demonstrates increased lucency in the subpulmonic recesses of both lungs which tracks along the inferior margin of the cardiac silhouette, crossing the midline into the contralateral side giving rise to the “continuous diaphragm” sign (black arrows).
Frontal and Cross Table X-Rays - Pneumatosis Intestinalis
Frontal and cross-table lateral radiographs of this infant’s chest and abdomen demonstrate extensive free air outlining the hepatic contour, prominent portal venous gas as well as bubbly lucency within the bowel indicating pneumatosis. The large amount of free air within the peritoneum is outlining multiple loops of bowel. This sign is called the Rigler’s sign. Football sign is another radiographic sign used to describe free air contained within the peritoneum and is well demonstrated on the lateral radiograph.

Selected References

  1. Bickle, I., & Shetty, A. (2020). Neonatal pneumothorax | Radiology Reference Article | Radiopaedia.org. Retrieved 13 September 2020, from https://radiopaedia.org/articles/neonatal-pneumothorax?lang=us
  2. Akin, K., Nevzat Cizmeci, M., Kenan Kanburoglu, M., Zulfikar Akelma, A., & Mansur Tatli, M. (2013). Angel Wing Sign in a Neonate with Pneumomediastinum. The Journal of Pediatrics, 163, 296. https://doi.org/10.1016/j.jpeds.2013.02.031de
  3. Lange, C. (2011). Radiology in paediatric non-traumatic thoracic emergencies. Insights into Imaging, 2(5), 585–598. https://doi.org/10.1007/s13244-011-0113-4

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