Pneumomediastinum

Perforation
des Ösophagus bei Ösophaguskarzinom: Im Röntgenbild des Thorax sieht man ein Mediastinal- / Weichteilemphysem. Gut zu erkennen ist die bandförmige Aufhellung um den Aortenbogen.
Wikipedia • CC BY-SA 4.0
Pneumomediastinum:
complication of an aspirated foreign body. Abundant subcutaneous emphysema (yellow arrows) and pneumomediastinum: tubular artery sign (red arrows), “ring around the artery” sign (blue triangle only in 1b) and continuous diaphragm sign (yellow triangle).
www.eurorad.org • CC by-nc-sa-4.0
Infant with
hematemesis who had an unsuccessful nasogastric tube placementCXR AP shows air outlining the heart in the pericardial space, air outlining the thymus in the mediastinum, and air in the bilateral pleural spaces.The diagnosis was pneumopericardium, pneumomediastinum, and pneumothorax due to esophageal perforation from traumatic nasogastric tube placement. A subsequent esophagram did not demonstrate a leak.
pediatricimaging.org • CC-by-nc-sa 4.0
Infant with
cough and fever. CXR AP and lateral (above) shows right upper lobe collapse and air outlining the inferior border of the heart (continuous diaphragm sign). Left lateral decubitus CXR (below) shows a small right pneumothorax.The diagnosis was pneumopericardium and pneumomediastinum and right pneumothorax in a patient with respiratory syncytial virus pneumonia.
pediatricimaging.org • CC-by-nc-sa 4.0
Mediastinalemphysem
(Pneumomediastinum) im Röntgenbild und in der Computertomographie (coronar). Man sieht im Röntgenbild die Linie parallel zum Mediastinum. In der CT erkennt man leicht die freie Luft, die sich als Weichteilemphysem bis in den Hals erstreckt. Rechts (links im Bild) auch ein auch kleiner interlobärer Pneumothorax.
Wikipedia • CC BY-SA 3.0
Macklin-Effekt
nach stumpfem Thoraxtrauma: Spontanes Pneumomediastinum ohne Nachweis einer tracheo-bronchialen oder Lungenverletzung.
Wikipedia • CC BY-SA 4.0
The
anatomical compartments and their connections as demonstrated by ectopic air. Local sources of pneumomediastinum. a, b Spontaneous pneumomediastinum due to prolonged and forceful Valsalva manoeuvres in 21-year-old man. Axial CT scan with “lung window” demonstrates the Macklin effect: air is seen along the perivascular and peribronchial fascial sheaths (a), continuous to the mediastinum (red star) (b). c Oesophageal perforation by fishbone complicated by mediastinitis in a 61-year-old woman. Axial CT scan after oral iodinated contrast ingestion, distending the oesophagus (red square); extraluminal air bubbles (red arrows) are seen in mediastinum together with increased mediastinal fat attenuation, as well as multiple reactive lymph nodes. Normal permeable airways are seen (blue triangle) at level of carina
insightsimaging.springeropen.com • Open Access
The
anatomical compartments and their connections as demonstrated by ectopic air. A 44-year-old man with silicosis and CPOD (chronic pulmonary obstructive disease), with an upper right lobe nodule, who developed secondary pneumothorax after biopsy; the lung did not expand with drainage, due to the development of broncho-pleural fistula; the drain was accidentally removed and the patient developed rapidly progressive emphysema. a Axial CT scan in lung windows depicts extensive subcutaneous emphysema and pneumomediastinum. b Axial CT scan 5 days later, shows that all ectopic air has been reabsorbed
insightsimaging.springeropen.com • Open Access
Premature
newborn with respiratory distress on a ventilatorCXR AP+lateral shows air around the thymus superiorly and air around the heart inferiorly. The diaphragm can be traced continuously across both images. There is also a small amount of air in the apex of the right pleural space.The diagnosis was pneumomediastinum and a small right apical pneumothorax in a patient with respiratory distress syndrome.
pediatricimaging.org • CC-by-nc-sa 4.0
Premature
newborn who has become more difficult to ventilateCXR AP shows a branching bubbly appearance to the right lung along with air in the superior mediastinum.The diagnosis was pulmonary interstitial emphysema and pneumomediastinum in a patient with respiratory distress syndrome.
pediatricimaging.org • CC-by-nc-sa 4.0
Weichteil-
und Mediastinalemphysem nach Rippenserienfraktur: Achte auf Doppellinie entlang des Aortenbogens und am Herzrand. Es war auch ein Pneumothorax vorhanden.
Wikipedia • CC BY-SA 4.0
Pneumomediastinum
• ERCP for pancreatic cancer complicated by perforation of pharyngeal pouch - Ganzer Fall bei Radiopaedia
Shah, V. ERCP for pancreatic cancer complicated by perforation of pharyngeal pouch. Case study, Radiopaedia.org. (accessed on 25 Oct 2022) https://doi.org/10.53347/rID-61056 • CC by-nc-sa 3.0 (modified)
Spontaneous
oesophageal perforation. Pneumomediastinum (green arrows). Pneumothorax (orange arrow) was also evident.
www.eurorad.org • CC by-nc-sa-4.0
Sudden
thoracic pain and dyspnea in a young adult. Enlarged view shows detachment of the parietal pleural from the trachea by air (blue arrow) and air outlining (yellow arrows) the right and left main bronchi (black asterisk) - Double bronchial wall sign.
www.eurorad.org • CC by-nc-sa-4.0
School ager
in a motor vehicle accident with respiratory distressCXR AP shows air in the superior mediastinum and neck, airspace disease in the left upper lobe, and a small amount of air in the left pleural space.The diagnosis was tracheobronchial injury of the left mainstem bronchus with pneumomediastinum and a small left pneumothorax.
pediatricimaging.org • CC-by-nc-sa 4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Pneumomediastinum is the presence of extraluminal gas within the mediastinum. Gas may originate from the lungs, trachea, central bronchi, esophagus, and peritoneal cavity and track from the mediastinum to the neck or abdomen.

Terminology

In the setting of trauma, if pneumomediastinum is visible on chest x-ray it is termed overt pneumomediastinum whereas if it is only visible on CT then it is termed occult pneumomediastinum .

Pathology

Etiology

Although it is rare, pneumomediastinum can occur spontaneously. This is considered benign and generally affects young adult males .

Radiographic features

Small amounts of gas appear as linear or curvilinear lucencies outlining mediastinal contours such as:

Pediatric pneumomediastinum may have slightly different appearances:

  • elevated thymus: thymic wing sign
  • gas crossing the superior mediastinum: haystack sign (the heart appears like a haystack in a Monet painting)
Ultrasound

Sonography is not a diagnostic modality of choice but is often used in the initial workup of undifferentiated trauma patients, or in differentiating causes of dyspnea or chest pain. Sonographic features which may appear in pneumomediastinum include :

  • cervical subcutaneous emphysema
    • anterior cervical ultrasonography demonstrates hyperechoic foci with "dirty" posterior acoustic shadowing
    • typically found anterior or lateral to the thyroid and medial to the internal jugular vein
  • loss of the parasternal and apical views when performing transthoracic echocardiography
    • with preservation of the subxiphoid window
  • the air gap sign
    • originally described using M-mode, describes systolic obscuration of cardiac structures as viewed from a parasternal long axis view
    • cyclic appearance of a dense band of horizontal reverberation artifacts which were discontinuous in the far field 

Differential diagnosis

Must be distinguished most importantly from:

For small gas collections on a CT scan, also consider :

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Mediastinalemphysem:
Pneumothorax
 
Wikipedia • CC BY-SA 4.0
Pneumoperikard
 
pediatricimaging.org • CC-by-nc-sa 4.0
interstitielles
Lungenemphysem
pediatricimaging.org • CC-by-nc-sa 4.0
Macklin-Effekt
bei stumpfem Thoraxtrauma
Wikipedia • CC BY-SA 4.0
Mediastinalemphysem
beim Neugeborenen
Wikipedia • CC BY-SA 4.0