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pneumothorax(no͞omōthôr`ăks), collapse of a lung with escape of air into the pleural cavity between the lung and the chest wall. The cause may be traumatic (e.g., gunshot or stab wound), spontaneous (rupture due to disease or localized weakness of the lung lining), or environmental (extreme change in atmospheric pressure). The only symptom may be a sudden pain in the chest. Physical and radiological examination reveals characteristic signs of lung collapse. Simple pneumothorax of only one lung generally requires only rest; the break in the pleura usually heals quickly after collapse of the lung has taken place. In tension pneumothorax (where there is high intrapleural pressure), or if both lungs are collapsed, it is mandatory to remove the air from the pleural cavity immediately. An artificial pneumothorax is one deliberately induced, as in the treatment of tuberculosis of the lung before modern drugs became available, or in the diagnosis of lung disease.
a condition characterized by the accumulation of air or gas in the pleural cavity. Three types are distinguished according to origin: traumatic, spontaneous, and artificial.
Traumatic pneumothorax arises as a result of both open chest wounds, such as knife or gunshot wounds, and closed injuries, with no breaking of the skin; either type of injury is accompanied by rupture of a lung. In an open pneumothorax constant communication is maintained between the pleural cavity and air outside the body. Spontaneous pneumothorax arises as a result of sudden impairment of lung tissue, as with pulmonary emphysema or rupture of congenital pulmonary cysts. In some cases, there may be a flap of lung tissue covering the site of the rupture; this flap functions as a valve to prevent air from returning to the bronchus during exhalation. Such a valvular pneumothorax is accompanied by complete collapse of the lung, which then loses respiratory function, and by displacement of the heart, folding of major blood vessels, and circulatory disturbances.
The main symptoms of pneumothorax are pain in the chest and dyspnea. Auscultation reveals weak or absent respiration on the affected side. Air may also accumulate in the subcutaneous tissue of the chest, neck, face, or mediastinum with characteristic distention and crackling sensation upon palpation; these conditions are called subcutaneous emphysema and mediastinal emphysema. Complications of pneumothorax include pleurisy and hemopneumothorax, which results from the entry of blood into the pleural cavity. First aid for open pneumothorax requires prompt application of a bandage to cover the wound. In valvular pneumothorax the pleural cavity must be punctured and the air removed to prevent the lung from collapsing and the heart from shifting.
Artificial pneumothorax, the intentional introduction of air into the pleural cavity to compress the lung, was proposed by the Italian physician C. Forlanini in 1882. It is now used in the treatment of cavernous forms of pulmonary tuberculosis.
REFERENCESpontannyi (patologicheskii) pnevmotoraks. Moscow, 1973.
L. S. TONINSKII and V. A. FROLOV