tension gastrothorax
Tension gastrothorax describes a rare life-threatening condition caused by mediastinal shift due to a distended stomach herniating into the thorax through a diaphragmatic defect.
Clinical presentation
Presentation is generally with acute and severe respiratory failure, with clinical features such as dyspnea, chest pain, and tachycardia being common . Case reports commonly detail clinical progression into shock and cardiac arrest .
Pathology
Tension gastrothorax requires a left-sided diaphragmatic defect to exist, and thus occurs in two different patient populations:
- congenital diaphragmatic defects: tend to present in infants as congenital diaphragmatic hernia, but approximately 10% present later in life, usually in childhood
- acquired diaphragmatic defects: most often due to traumatic diaphragmatic rupture, enlarging hiatus hernia, or from repair of hiatus hernia, and thus tend to be present in an adult demographic
The pathophysiology is thought to be due to an instance of significantly increased intra-abdominal pressure (e.g. blunt trauma, Valsalva maneuver, pregnancy) which results in herniation of the stomach through the left-sided diaphragmatic defect into the thorax . The exact mechanism of how or when this herniated stomach becomes rapidly filled with air is unclear, but potentially an abnormally positioned gastro-esophageal junction that prevents belching may be the trigger for the formation of a one-way valve and therefore resultant tension gastrothorax .
Similarly to a tension pneumothorax, this air collection can grow and expand until it exerts a positive mass effect on the mediastinum, eventually resulting in respiratory and cardiac arrest .
Radiographic features
Plain radiograph
Chest radiographs demonstrate a large air-filled lucent structure in the left hemithorax causing contralateral mediastinal shift . In differentiating it from a tension pneumothorax, the following are useful:
- the left hemidiaphragm is poorly defined
- there may be a fluid level in the left hemithorax
- lack of a gastric bubble
CT/MRI
These cross-sectional modalities will allow the best visualization of the tension gastrothorax, but are rarely available in an emergency situation .
Treatment and prognosis
Prompt management with nasogastric tube insertion to decompress the stomach is necessary to prevent further clinical deterioration . The patient’s diaphragmatic defect should then be surgically repaired once stable .
History and etymology
The term 'gastrothorax' was first used in the literature by American emergency physician Gary Ordog and his colleagues in 1984 in the context of a tension gastrothorax occurring after trauma .
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