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pneumomediastinum; mediastinal emphysema
Air in the mediastinum. See pneumothorax
Etiology:
- tracheobronchial injury resulting from
- trauma to the chest wall
- acute asthma exacerbation
- clinical procedures procedures
- bronchoscopy
- esophagoscopy (Boerhaave syndrome)
- air entering mediastinum from the retroperitoneal space
- Mycoplasma pneumonia
- obesity
Pathology:
- rupture of aveoli resulting from small airway obstruction
- movement of free air along the airways & blood vessels to the mediastinum by dissecting through supporting soft tissue
Clinical manifestations:
- severe central chest pain, neck pain, throat pain
- dsypnea, cough, wheezing
- voice distortion
- subcutaneous emphysema, affecting face, neck, & chest
- Hamman's sign
- crunching, rasping sound, synchronous with the heartbeat, heard on ausculation over the precordium (crunching sound during systole) [5]
- crepitus with palpation of midline upper thorax [5]
Radiology:
- chest X-ray shows a white outline around the heart & mediastinum
- CT of the thorax
Differential diagnosis:
- cardiac tamponade
Management:
- conservative management
- spontaneous resolution common
- high flow oxygen as needed
- pain management
- avoidance of actions that increase pulmonary pressure
- needle decompression for cardiogenic shock
- if collapsed lung, lie on side of collapsed lung, manage pain
- treat asthma exacerbation
- surgery may be needed to repair trachea, esophagus or bowel may be indicated
General
pneumothorax
emphysema
References
- Wikipedia: Pneumomediastinum
https://en.wikipedia.org/wiki/Pneumomediastinum
- Gray JM, Hanson GC
Mediastinalemphysema: aetiology,diagnosis, andtreatment
Thorax(1966),21,325
http://thorax.bmj.com/content/21/4/325.full.pdf
- Weissberg D, Weissberg D.
Spontaneous mediastinal emphysema.
Eur J Cardiothorac Surg. 2004 Nov;26(5):885-8.
PMID: 15519
http://ejcts.oxfordjournals.org/content/26/5/885.long
- MedlinePlus: Pneumomediastinum
https://www.nlm.nih.gov/medlineplus/ency/article/000084.htm
- NEJM Knowledge+ Question of the Week. Oct 17, 2023
https://knowledgeplus.nejm.org/question-of-week/4784/
- Gasser CR, Pellaton R, Rochat CP.
Pediatric Spontaneous Pneumomediastinum: Narrative Literature Review.
Pediatr Emerg Care. 2017 May;33(5):370-374.
PMID: 26855340 Review
- Fitzwater JW, Silva NN, Knight CG et al
Management of spontaneous pneumomediastinum in children.
J Pediatr Surg. 2015 Jun;50(6):983-6.
PMID: 25840604
- Abbas PI, Akinkuotu AC, Peterson ML, Mazziotti MV.
Spontaneous pneumomediastinum in the pediatric patient.
Am J Surg. 2015 Dec;210(6):1031-5; discussion 1035-6.
PMID: 26467078