Tension pneumothorax secondary to a gastropleural fistula in a traumatic diaphragmatic hernia. We report a case of tension pneumothorax due to a gastropleural fistula resulting from perforation of the stomach in a traumatic diaphragmatic hernia. Awareness of perforation of strangulated stomach or bowel in a diaphragmatic hernia as a cause of pneumothorax, with or without tension physiology, in a patient with a history of trauma is important so that surgical repair can be undertaken without delay. 