Pneumomediastinum. Note lucency between left heart border and mediastinum

Pneumomediastinum = air in mediastinum

Spontaneous - without clear cause

  • Young men
  • Assumed alveolar rupture, air tracking centrally along vessels
  • Lung disease predispose e.g. fibrosis, pneumonitis, emphysema, ARDS
  • Barotrauma
    • High airway pressures -asthma, FB, mechanical ventilation
    • Blunt trauma, coughing, vomiting or valsalva
    • Cocaine and marijuana (valsalva and high inspiration pressures)


  • Following trauma, infection, oesophageal # etc


  • Chest pain (± pleuritic, radiating to back)
  • SOB (rarely cough)
  • Neck pain (vague odynophagia)
  • May have palpable neck surgical emphysema
  • Check for Hamman's crunch

Differential Dx


  • PA (only 50% sensitive) and lateral (retrosternal lucency) CXR
  • CT if clinically convincing but CXR normal, or to out-rule 2° cause

Exclude secondary (life threatening) causes

  • N.B. vomiting induced oesophageal # ?
  • Any recent ENT/Mediastinal infections?
  • Any recent GI procedures / symptoms?
  • Upper GI malignancy?
  • Airway pressures / FB?


  • Supportive (O2, analgesia)if spontaneous, ± check CXR if persisting symptoms
  • Treat underlying cause if secondary
  • Same advice as spontaneous PTX (scuba diving / flying etc)

Content by Dr Íomhar O' Sullivan. last review DR ÍOS 13/12/21.