Pneumothorax is a condition where air leaks into the space between the lung and chest wall, causing the lung to collapse. It can be caused by a blunt or penetrating chest injury, certain medical procedures, or damage from underlying lung disease. Symptoms of pneumothorax include sudden chest pain and shortness of breath, which may depend on how much of the lung is collapsed. If the pneumothorax is minor, the doctor may simply watch the patient for signs of heart or breathing problems, and the lung may re-inflate on its own over the course of several weeks. For more serious cases, treatment may include supplemental oxygen, needle aspiration, chest tube drainage, or surgery. Risk factors for pneumothorax include smoking, tall thin body habitus, pregnancy, Marfan syndrome, COPD, asthma, and HIV with pneumocystis pneumonia.