A 27-year-old man is brought to the emergency department after a high-speed motor vehicle collision. On arrival, his blood pressure is 90/52 mm Hg, pulse is 122/min, and respirations are 30/min. The patient is in moderate respiratory distress. There are bruises on the anterior chest wall and abdomen. No breath sounds are heard in the left lung, and initial chest x-ray shows hemopneumothorax. Fluid resuscitation is given, left-sided chest tubes and a nasogastric tube are placed, and the patient is admitted to the trauma floor after stabilization. Four days later, the chest tubes continue to drain appropriate serosanguinous fluid, but the patient still feels short of breath. He has an occasional dry, nonproductive cough. Current temperature is 36.8 C (98.2 F), blood pressure is 118/78 mm Hg, pulse is 88/min, and respirations are 20/min. A repeat chest x-ray shows the following.
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Which of the following is the most likely cause of the patient's continued respiratory distress?
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This patient experienced blunt thoracoabdominal trauma (motor vehicle collision, anterior chest wall bruises) resulting in hemopneumothorax that required chest tube placement. He now has continued shortness of breath despite appropriate chest tube drainage. A repeat chest x-ray shows that the chest tubes (shown in green) are in place; however, the nasogastric tube (shown in blue), correctly positioned along the greater curvature of the stomach, is located abnormally in the left hemithorax. This presentation is consistent with diaphragmatic hernia.
Blunt thoracoabdominal trauma causes diaphragmatic rupture by a sudden increase in pressure that creates large radial tears or avulsion from side wall attachments. The diaphragmatic defect allows migration of intra-abdominal contents into the chest (ie, diaphragmatic hernia) with resulting symptoms due to lung compression (eg, respiratory distress) or bowel obstruction (eg, nausea, vomiting, abdominal pain). Most patients with diaphragmatic rupture require immediate treatment, often with associated injuries. However, some patients with smaller ruptures can have a delayed presentation (as seen in this case) when defects enlarge over time.
Diagnosis is made with imaging. Chest x-ray may show abdominal organs within the chest (with or without mediastinal deviation) but is typically nondiagnostic (elevation of the hemidiaphragm may be the only abnormal finding). CT scans of the chest and abdomen are usually required to confirm the diagnosis. Patients require surgical repair because diaphragmatic hernia can potentially result in intestinal strangulation and death.
(Choice A) Aortic rupture usually results in instantaneous death. Patients with contained ruptures may rarely survive to have severe chest pain, hypotension, and a widened mediastinum on chest x-ray.
(Choice C) Flail chest, caused by fracture of ≥3 adjacent ribs in ≥2 places, can produce respiratory distress due to the unstable segment moving paradoxically to respiration. Rib fractures are not present on this chest x-ray.
(Choice D) Left lower lobe pneumonia may cause consolidation on chest x-ray but usually includes symptoms of fever and productive cough. This patient's intrathoracic nasogastric tube is more consistent with a diaphragmatic hernia.
(Choice E) Trauma and immobility both increase the risk of deep venous thrombosis in this patient, but pulmonary embolism typically presents with a normal chest x-ray.
(Choice F) Recurrent pneumothorax is unlikely with functioning chest tubes. In addition, a visceral pleural line would be seen on chest x-ray, separated from the parietal pleura by radiolucent gas.
Educational objective:
Diaphragmatic rupture can have a delayed presentation after blunt thoracoabdominal trauma due to progressive enlargement of the diaphragmatic defect and herniation of abdominal organs into the thoracic cavity. Chest x-ray may show elevation of the hemidiaphragm or abdominal organs (eg, stomach) in the thorax.