II. Definitions
- Pneumomediastinum
- Free air within the mediastinal space
III. Pathophysiology
- Sources
- Spontaneous rupture of alveolus or bleb
- Tracheobronchial Injury (Trauma)
- Boerhaave's Syndrome (Esophageal Rupture)
- Results from increased pressure gradient
- Negative (Inhalation)
- Positive (Valsalva)
- Air tracks along vessels and Bronchi
- Air coalesces in mediastinum
IV. Causes
- Secondary Pneumomediastinum (may be life-threatening)
- Tracheobronchial Injury (Trauma, Foreign Body Aspiration)
- Boerhaave's Syndrome (Esophageal Rupture, sharp Foreign Body Ingestion)
- Blunt Chest Injury (Pneumothorax, Rib Fracture, Sternal Fracture)
- Spontaneous Pneumomediastinum (tends to be benign)
- Inhalation Drug Use (e.g. Huffing)
- Inhalation Drug Users may perform action similar to Muller Maneuver
- Forced inspiration against a closed mouth and nose (opposite Valsalva Maneuver)
- Asthma
- Coughing
- Vomiting or Retching
- Weight lifting
- Vaginal Delivery
- Mechanical Ventilation
- Inhalation Drug Use (e.g. Huffing)
V. Symptoms
- Sore Throat
- Dyspnea
-
Pleuritic Chest Pain
- Worse with lying
- Better with sitting
VI. Signs
- Subcutaneous Emphysema
-
Hamman's Crunch (50%)
- Precordial systolic crepitation sound heard synchronous with heart beat
-
Hamman Sign
- Diminished heart sounds
VII. Differential Diagnosis
VIII. Labs
- Complete Blood Count
- C-Reactive Protein
- Serum Lactate
IX. Imaging
-
Chest XRay
- As many as 50% Pneumomediastinum cases are missed on PA Chest XRay
- Observe for a stripe of air extending superiorly from hilum, parallel to mediastinum
- Outlines mediastinal anatomy (pulmonary artery, major aortic branches and Bronchial wall)
- Review Lateral Chest XRay carefully
- Consider lateral neck XRay
- Air tracks between posterior pharyngeal wall and Vertebrae
- Air is more easily seen on this view, than Chest XRay
- Named Signs
- Naclerio V Sign
- Sharp, well demarcated "V" along the left heart border and left diaphragm
- Continuous Diaphragm Sign
- Air below and posterior to the heart results in a continuous line across the diaphragm
- Tubular Artery Sign
- Major aortic branches highlighted with double line
- Ring Around the Artery Sign
- Pulmonary artery and main branches highlighted with double line
- Naclerio V Sign
- As many as 50% Pneumomediastinum cases are missed on PA Chest XRay
- Chest CT
X. Management
- Primary Pneumomediastinum (e.g. due to excessive coughing, Asthma)
- Often a benign, incidental finding on CT Imaging
- Analgesics
- Rest
- Secondary Pneumomediastinum (e.g. Tracheobronchial Injury, Esophageal Rupture) or increased inflammatory markers
- Serious, potentially life threatening finding
- Intensive Care Unit Admission and thoracic surgery Consultation
XI. Complications
- Tension Pneumomediastinum (rare)
- Emergent thoracic surgery Consultation
- Presents with Hypotension
- Acute stabilization requires suprasternal notch Blunt Dissection (relieves tension)
- Avoid worsening intrathoracic pressure
- Intubated patients should be allowed permissive hypercapnia to limit airway pressures
XII. References
- Dreis (2020) Crit Dec Emerg Med 34(7):3-21
- Swadron (2019) Pulmonology 2, CCME Board Review, accessed 6/18/2019
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Related Studies
| Definition (NCI_NICHD) | Mediastinal emphysema is a condition in which air is present in the mediastinum. It can result from physical trauma or other situations that lead to air escaping from the lungs, airways or bowel into the chest cavity. |
| Definition (NCI) | The presence of air in the mediastinum. It is caused by injury, most often esophageal or intestinal perforation. |
| Definition (MSH) | Presence of air in the mediastinal tissues due to leakage of air from the tracheobronchial tree, usually as a result of trauma. |
| Concepts | Pathologic Function (T046) |
| MSH | D008478 |
| ICD10 | J98.2 |
| SnomedCT | 155627006, 390899006, 196144009, 266411000, 16838000 |
| English | Emphysema, Mediastinal, Emphysemas, Mediastinal, Mediastinal Emphysema, Mediastinal Emphysemas, Pneumomediastinum, mediastinal emphysema (diagnosis), mediastinal emphysema, Mediastinal Emphysema [Disease/Finding], pneumomediastinum, Pmeumomediastinum, Mediastinal emphysema, Mediastinal emphysema (disorder), emphysema; mediastinal, mediastinal; emphysema, Mediastinal emphysema [Ambiguous] |
| Dutch | mediastinaal emfyseem, emfyseem; mediastinaal, mediastinaal; emfyseem, pneumomediastinum, Emfyseem, mediastinum-, Mediastinumemfyseem, Pneumomediastinum |
| German | mediastinales Emphysem, Emphysem, Mediastinal-, Mediastinalemphysem, Pneumomediastinum |
| Italian | Enfisema del mediastino, Pneumomediastino, Enfisema mediastinico |
| Portuguese | Enfisema do mediastino, Pneumomediastino, Enfisema Mediastínico |
| Spanish | Enfisema mediastínico, enfisema mediastinal, neumomediastino, enfisema del mediastino (trastorno), enfisema del mediastino, enfisema mediastínico, Pneumomediastino, Enfisema Mediastínico, Neumomediastino |
| Japanese | 気縦隔症, ｼﾞｭｳｶｸｷｼｭ, ｷｼﾞｭｳｶｸｼｮｳ, 気腫-縦隔, 縦隔気腫 |
| Swedish | Mediastinalt emfysem |
| Czech | mediastinum - emfyzém, pneumomediastinum, Pneumomediastinum, Mediastinální emfyzém |
| Finnish | Välikarsinan ilmapöhö |
| Russian | PNEVMOMEDIASTINUM, EMFIZEMA MEDIASTINAL'NAIA, SREDOSTENIIA EMFIZEMA, ПНЕВМОМЕДИАСТИНУМ, СРЕДОСТЕНИЯ ЭМФИЗЕМА, ЭМФИЗЕМА МЕДИАСТИНАЛЬНАЯ |
| Croatian | SREDOPRSJE, EMFIZEM, EMFIZEM MEDIJASTINUMA, MEDIJASTINUM, EMFIZEM |
| Polish | Odma śródpiersiowa |
| Hungarian | Mediastinalis emphysema, Pneumomediastinum |
| Norwegian | Mediastinalemfysem, Pneumomediastinum, Mediastinumemfysem, Emfysem, mediastinalt, Mediastinalt emfysem |
| French | Pneumomédiastin, Emphysème du médiastin, Emphysème médiastinal |
