A pregnant 26-year-old woman with a one-week history of nausea and vomiting presented to the emergency department with dyspnea and left-sided chest pain. Her heart rate was 105 beats per minute; otherwise her vital signs were normal. Her oxygen saturation was 90 percent. Her physical examination was remarkable only for a gravid abdomen with minimal flank tenderness and absent breath sounds over the left side of the chest. She had no recent history of trauma.
The chest radiograph (see accompanying figure) was interpreted as showing a left pneumothorax with mediastinal structures shifted to the right. A left-sided chest tube was placed.
The answer is A: tension gastrothorax. The mediastinal structures are shifted to the right and an air/fluid level, contained within the distended stomach, is seen in the left hemithorax. The left lung is not visible because the stomach displaces the entire contents of the left hemithorax. The faint gas shadows overlying the gastric fluid (representing gas in bowel loops) seen on chest radiograph are a final clue that the correct diagnosis is gastrothorax rather than pneumothorax.
Tension gastrothorax is a rare condition that occurs when the stomach (often accompanied by other normally intra-abdominal organs) herniates through a ruptured or incompetent diaphragm into the chest. Gastric or enteric distension then may cause a shift of mediastinal structures.1 Diaphragmatic tears are difficult to diagnose and will enlarge over time if not repaired.2 In the case of suspected diaphragm rupture, a nasogastric tube may appear coiled in the thorax on chest radiograph.2
Tension pneumothorax occurs when pleural damage results in a one-way valve phenomenon allowing air to enter, but not exit, the pleural space. Air accumulation collapses the lung and pushes mediastinal structures aside, resulting in characteristic physical findings such as air hunger, tachycardia, hypotension, tracheal shift, and jugular venous distension. In a simple pneumothorax, air in the potential space between the pleural surfaces of the lung and thorax causes the lung to collapse. A hemopneumothorax is the presence of blood and air in the pleural space. Pus accumulation in the pleural space is defined as a pleural empyema.
The patient in this case was diagnosed initially with a pneumothorax and received a tube thoracotomy. On insertion, the chest tube returned thin, yellow fluid with a pH level of 3.0. This was consistent with gastric fluid, and shortly thereafter the patient underwent operative repair of her left hemidiaphragm. Her massively distended stomach, which had been perforated by the chest tube, was found to occupy the apex of the left hemithorax. Although she had no recent history of trauma, in the remote past she had abdominal trauma that she had chosen not to have repaired. This may have been a diaphragmatic injury, which would predispose her to the development of a gastrothorax.
|Condition||Physical examination characteristics|
|Tension gastrothorax||Bowel sounds over the chest, hyperresonance to percussion|
|Hemopneumothorax||Percussion “dullness” over fluid, hyperresonance over air|
|Pleural empyema||Percussion “dullness” over fluid|
|Tension pneumothorax||Hyperresonance, vital sign instability, tracheal shift, jugular venous distension|