Pneumothorax is an abnormal collection of air in the pleural cavity. This can result in a partial or complete collapse of the lung. It may be caused by trauma or a medical procedure, or it may occur spontaneously. In certain cases, pneumothorax may be a life-threatening emergency, either due to respiratory failure or cardiovascular collapse. Patients with small pneumothorax may sometimes be asymptomatic. Common pneumothorax symptoms include chest or shoulder pain, dyspnea, tachycardia, and tachypnea.

Primary spontaneous pneumothorax typically occurs in patients without underlying lung disease. Classic presentation includes a tall, thin, young male patient in his teens or 20s. The spontaneous rupture of subpleural apical blebs or bullae may result from an inherited cause (eg, Marfan syndrome) or smoking or drug use. Primary spontaneous pneumothorax will typically occur while a patient is at rest; however, it may occur during physical activities such as reaching or stretching. Pressure changes in the lung that occur during diving and flying at high altitudes may also bring about primary spontaneous pneumothorax.

Secondary spontaneous pneumothorax usually occurs in patients with underlying lung diseases, such as asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, Pneumocystis jirovecii infection, tuberculosis, or whooping cough. This often occurs secondary to bleb rupture. Pneumothorax has been reported as a complication of chemotherapy. Other drugs have also been implicated. Secondary spontaneous pneumothorax is typically more serious than primary spontaneous pneumothorax.

Catamenial pneumothorax is a rare form of spontaneous pneumothorax occurring most commonly after the onset of menstruation in premenopausal women and less commonly in menopausal women taking estrogen. It is caused by intrathoracic endometriosis.

Traumatic pneumothorax is a complication of a blunt or penetrating chest injury.

Iatrogenic pneumothorax is caused by medical procedures, such as central venous catheter placement, mechanical ventilation, transthoracic needle aspiration, and cardiopulmonary resuscitation.

Related topic: Tension pneumothorax