Pneumomediastinum

Background

• Usually occurs with sudden increase in intra-alveolar pressure causing alveolar rupture, air dissects into pulmonary interstitium and then into mediastinum, neck, or pericardium
• Life threatening cause is esophageal rupture
• If no hemodynamic or airway compromise present, spontaneous pneumomediastinum is not a life threatening condition 

Causes

• Illegal drug use

1. Inhaling cocaine
2. Smoking cocaine
3. Smoking marijuana

• Vomiting
• Retching
• Coughing
• Asthma
• Esophageal rupture
• Recent endoscopy
• Trauma
  • Search for other more serious injuries (larynx, bronchus, esophagus)

Clinical Features

• Chest pain
  • Voice change, cough, stridor
• SubQ emphysema in chest wall, neck, face, abdomen, scrotum
• "Hamman's Crunch" - crunching sound of heart during systole

Workup

• CXR
  • AP/PA - Ring around right pulmonary artery, air along L heart border, air in upper chest/neck soft tissue
  • Lateral - air along anterior heart border
• Rule-out esophageal rupture by hx and exam or with esophagoscopy if indicated

Differential Diagnosis

Chest pain

Critical

• Acute coronary syndromes (ACS)
  • STEMI
  • Non-STEMI
  • Unstable angina
• Aortic dissection
• Cardiac tamponade
• Coronary artery dissection
• Esophageal perforation (Boerhhaave's syndrome)
• Pulmonary embolism
• Tension pneumothorax

Emergent

• Cholecystitis
• Cocaine-associated chest pain
• Mediastinitis
• Myocardial rupture
• Myocarditis
• Pancreatitis
• Pericarditis
• Pneumothorax

Nonemergent

• Aortic stenosis
• Arthritis
• Asthma exacerbation
• Biliary colic
• Costochondritis
• Esophageal spasm
• Gastroesophageal reflux disease
• Herpes zoster / Postherpetic Neuralgia
• Hypertrophic cardiomyopathy
• Hyperventilation
• Mitral valve prolapse
• Panic attack
• Peptic ulcer disease
• Pleuritis
• Pneumomediastinum
• Pneumonia
• Rib fracture
• Stable angina
• Thoracic outlet syndrome
• Valvular heart disease
• Muscle sprain
• Psychologic / Somatic Chest Pain
• Spinal Root Compression
• Tumor

Thoracic Trauma

• Airway/Pulmonary
  • Bronchial injury
  • Diaphragmatic trauma
  • Hemothorax
  • Pneumomediastinum
  • Pulmonary contusion
  • Tracheal injury
  • Trachobronchial injury
  • Traumatic pneumothorax
    • Tension pneumothorax
• Cardiac/Vascular
  • Cardiac injury
    • Blunt cardiac injury
      • Cardiac contusion
      • Commotio cordis
    • Penetrating cardiac injury
    • Cardiac tamponade
  • Traumatic aortic transection
• Musculoskeletal
  • Clavicle fracture
    • Clavicle fracture (peds)
  • Rib fracture
    • Flail chest
  • Scapular fracture
  • Scapulothoracic dissociation
  • Sternoclavicular dislocation
  • Sternum fracture
  • Thoracic and lumbar fractures and dislocations
• Other
  • Esophageal injury or Perforation
  • Pneumomediastinum
  • Pneumopericardium
  • Traumatic asphyxia

Management

• Supportive
  • No specific therapy for spontaneous pneumomediastinum
• Treat underlying cause

Disposition

• Depends on underlying cause and severity of condition
• Most pts with spontaneous pneumomediastinum, not caused by trauma or esophageal rupture, can be safely discharged

See Also

• Thoracic Trauma
• Mediastinitis

Sources

Harwood-Nuss, Rosens

Background

• Also known as mediastinal emphysema
• Definition: air present in the mediastinum

Causes

• Esophageal rupture
• Asthma/COPD
• Bowel rupture or other cause of air in abdominal cavity (tracts up into the chest)
• Mycoplasma pneumoniae pneumonia
• Environmental barotrauma (e.g. scuba diving, flight)
• Iatrogenic (e.g. during thoroscopy/VATS)
• Blunt chest trauma

Clinical Features

• Chest pain
• Dyspnea
• Voice distortion
• Subcutaneous emphysema, especially of face, neck, and chest.
• "Crunching" sound on auscultation, timed with the cardiac cycle (Hamman's crunch)
• May mimic cardiac tamponade

Diagnosis

Traumatic pneumomediastinum and right sided pneumothorax with first rib fracture.

Pneumomediastinum with Angel wing sign

• CXR or chest CT
  • Radiolucent outline around the heart and mediastinum

Management

• Supplemental oxygen with non-rebreather

See Also

• Pneumothorax (main)