Pneumomediastinum

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Background

  • Also known as mediastinal emphysema
  • Definition: presence of free air in the mediastinum
  • Can be Spontaneous or secondary (to violation of aerodigestive tract)[1]
  • Spontaneous pneumomediastinum usually occurs due to sudden increase in intra-alveolar pressure causing alveolar rupture → air dissects into pulmonary interstitium and then into mediastinum, neck, or pericardium[2]
  • Life threatening causes include esophageal rupture or tension pneumothorax

Causes

  • Primary (spontaneous) pneumomediastinum
  • Secondary pneumomediastinum
    • Iatrogenic - e.g. thoroscopy, VATS, bronchoscopy, colonoscopy or endoscopy
    • Blast injury
    • Thoracic trauma

Clinical Features

Differential Diagnosis

Chest pain

Critical

Emergent

Nonemergent

Thoracic Trauma

Evaluation

Pneumomediastinum from nasal insufflation of cocaine.
Traumatic pneumomediastinum and right sided pneumothorax with first rib fracture.
Pneumomediastinum with Angel wing sign
Pneumomediastinum with subcutanous emphysema on CT.
  • CT Chest (preferred diagnostic test)
  • CXR
    • AP/PA - Ring around right pulmonary artery, air along left heart border, air in upper chest/neck soft tissue
    • Lateral - air along anterior heart border
    • Lateral neck - may see mediastinal air in neck
    • 30% with spontaneous pneumomediastinum will have normal CXR[1]

Management

  • Supportive care[3]
    • Pneumomediastinum typically reabsorbs over 1-2 weeks.
  • Treat underlying cause, if identified

Disposition

  • Spontaneous pneumomediastinum
    • Benign and self-limited disease
    • Generally does not require repeat imaging, and can be managed conservatively on an outpatient basis[1][7][8]
  • Secondary pneumomediastinum[9]
    • Most cases are benign, but a minority of cases require additional testing and intervention.
    • Have lower threshold for additional testing and admission.

See Also

External Links

References

  1. 1.0 1.1 1.2 1.3 Bakhos CT, Pupovac SS, Ata A, et al. Spontaneous pneumomediastinum: an extensive workup is not required. J Am Coll Surg. 2014 Oct;219(4):713-7. doi: 10.1016/j.jamcollsurg.2014.06.001.
  2. 2.0 2.1 Niehaus M, Rusgo A, Roth K, Jacoby JL. Retropharyngeal air and pneumomediastinum: a rare complication of influenza A and asthma in an adult. Am J Emerg Med. 2015 Jun 14. pii: S0735-6757(15)00495-7. doi: 10.1016/j.ajem.2015.06.020.
  3. 3.0 3.1 Johnson JN, Jones R, Wills BK. Spontaneous Pneumomediastinum. Western Journal of Emergency Medicine. 2008;9(4):217-218.
  4. Quresi SA, Tilyard A (2008). "Unusual Presentation of Spontaneous Mediastinum: A Case Report". Cases Journal 1:349. doi:10.1186/1757-1626-1-349
  5. Beg MH, Reyazuddin, Ansari MM (1988). "Traumatic tension Pneumomediastinum Mimicking Cardiac Tamponade". Thorax 43:576-677. doi: 10.1136/thx.43.7.576.
  6. Jennings S, Peeceeyen S, Horton M. Tension pneumomediastinum after blunt chest trauma. ANZ J Surg. 2015 Jan;85(1-2):90-1. doi: 10.1111/ans.12378.
  7. Fitzwater JW, Silva NN, Knight CG, et al. Management of spontaneous pneumomediastinum in children. J Pediatr Surg. 2015 Jun;50(6):983-6. doi: 10.1016/j.jpedsurg.2015.03.024.
  8. Smith BA, Ferguson DB. Disposition of spontaneous pneumomediastinum. Am J Emerg Med. 1991 May;9(3):256-9.
  9. de Virgilio C, Kim DY. Pneumomediastinum Following Blunt Trauma: Are We Closer to Unlocking Its Significance? JAMA Surg. 2015 Jun 24. doi: 10.1001/jamasurg.2015.1146.