This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart & Pericardium, Subject name: Surgery
[{'content': 'A previously healthy 20-year-old man is admitted to a hospital with acute onset of left-sided chest pain. The electrocardiographic findings are normal but chest x-ray shows a 40% left pneumothorax. Treatment consists of which of the following procedures? \nSelect and explain. \nA. Observation, B. Barium swallow, C. Thoracotomy, D. Tube thoracostomy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Spontaneous pneumothorax usually results from the rupture of subpleural blebs in young men (age 20-40), which is often signaled by a sudden onset of chest and shoulder pain. Pneumothorax of more than 25% requires placement of a chest tube; thoracotomy with bleb excision and pleural abrasion is generally recommended if spontaneous pneumothorax is recurrent. Small pneumothoraxes in patients with minimal symptoms usually resolve and therefore can be observed. A spontaneous perforation of the esophagus (Boerhaave syndrome) can result in hydropneumothorax as well as the more usual pneumomediastinum but would not present with an isolated 40% pneumothorax. Barium swallow is an appropriate diagnostic test for evaluation of a suspected leaking esophagus.', 'role': 'assistant'}]