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
Etiology[3]
Primary (i.e. Spontaneous)
- No identified cause
- Smoking or tobacco use
- Recreational drug inhalation (cocaine, methamphetamine, marijuana)[4]
Secondary
- Intrinsic Lung and Airway
- Asthma / COPD (most common co-morbidity[1])
- Bronchiectasis
- Interstitial lung disease
- Lung cancer
- Foreign body in the airway
- Childbirth
- Excessive vomiting (i.e., Boerhaave syndrome, anorexia nervosa)
- Excessive coughing (i.e., asthma exacerbation)
- Strenuous physical activities
- Iatrogenic
- Endoscopy
- Intubation
- Central venous access procedures
- Thoracostomy
- Chest or abdominal surgeries
- Traumatic
- Blunt trauma
- Penetrating trauma
- Blast injury
- Hydrocarbon inhalation
- Influenza A[2]
- Environmental pulmonary barotrauma (e.g. scuba diving, flight)
- Bowel rupture or other cause of air in abdominal cavity (tracts up into the chest)
- Mycoplasma pneumoniae pneumonia
- Esophageal rupture (rare)
- Iatrogenic - e.g. thoracoscopy, VATS, bronchoscopy, colonoscopy or endoscopy
- Blast injury
- Thoracic trauma
Clinical Features
- Chest pain
- Dyspnea
- Subcutaneous emphysema, especially of face, neck, and chest.[5]
- Voice change, cough, stridor
- "Crunching" sound on auscultation during systole (Hamman's crunch)
- Severe cases (generally after trauma) may mimic cardiac tamponade[6][7]
Differential Diagnosis
Chest pain
Critical
- Acute coronary syndromes (ACS)
- 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
- Cardiac/Vascular
- Musculoskeletal
- Other
Evaluation
- 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[4]
- Pneumomediastinum typically reabsorbs over 1-2 weeks.
- Treat underlying cause, if identified
Disposition
Primary (Spontaneous)
- Benign and self-limited disease
- Generally does not require repeat imaging, and can be managed conservatively on an outpatient basis[1][8][9]
Secondary[10]
- 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
- ↑ 1.0 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.
- ↑ 2.0 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.
- ↑ Kouritas VK, et al. Pneumomediastinum. J Thorac Dis. 2015 Feb; 7(Suppl 1): S44–S49. doi: 10.3978/j.issn.2072-1439.2015.01.11
- ↑ 4.0 4.1 Johnson JN, Jones R, Wills BK. Spontaneous Pneumomediastinum. Western Journal of Emergency Medicine. 2008;9(4):217-218.
- ↑ Quresi SA, Tilyard A (2008). "Unusual Presentation of Spontaneous Mediastinum: A Case Report". Cases Journal 1:349. doi:10.1186/1757-1626-1-349
- ↑ Beg MH, Reyazuddin, Ansari MM (1988). "Traumatic tension Pneumomediastinum Mimicking Cardiac Tamponade". Thorax 43:576-677. doi: 10.1136/thx.43.7.576.
- ↑ 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.
- ↑ 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.
- ↑ Smith BA, Ferguson DB. Disposition of spontaneous pneumomediastinum. Am J Emerg Med. 1991 May;9(3):256-9.
- ↑ 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.