PNEUMOTHORAX



The most common causes of air in the pleural space are listed in . Idiopathic spon­taneous pneumothorax typically causes dyspnea, chest pain, and few abnormalities on physical ex­amination. On chest x-ray, the one-dimensional view grossly underestimates its true volume. Without surgery, 50 per cent develop a recur­rence, usually within two years. Unlike the low mortality with idiopathic pneumothorax, that due to underlying lung disease has a 15 per cent mor­tality rate. Under certain circumstances, particu­larly in patients on mechanical ventilators, the rent in the pleura forms a one-way valve that per­mits air to enter but not escape and positive pres­sure builds up in the chest (tension pneumo­thorax).

Treatment depends on the amount of air and the underlying status of the patient. Spontaneous pneumothorax in a healthy asymptomatic patient may require no treatment, whereas treatment is required for the same size pneumothorax in a pa­tient with cardiopulmonary insufficiency. Treat­ment is almost always required for pneumothor-aces greater than 50 per cent in size and for a pneumothorax of any size in patients on mechan­ical ventilation or with diffuse lung disease. Drainage by tube thoracostomy is successful in most instances, and instillation of tetracycline to produce pleurodesis may prevent recurrences. Sometimes open thoracotomy with partial pleu-rectomy and oversewing of apical blebs or abra­sion of the pleural surface is required.