Aetiology
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)
Secondary
- Following trauma, infection, oesophageal # etc
Clinical
- 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
- Musculoskeletal
- Acute Coronary Syndrome
- Pneumothorax, pneumonia or tracheobronchial disruption
- Costochondritis
- Pericarditis
- Oesophageal # (Boerhaave's synd)
Investigations
- 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?
Treatment
- Supportive (O2, analgesia)if spontaneous, ± check CXR if persisting symptoms
- Treat underlying cause if secondary
- Same advice as spontaneous PTX (scuba diving / flying etc)