A secondary spontaneous pneumothorax (SSP) is defined as a pneumothorax that occurs as a complication of underlying lung disease [1,2]. In contrast, primary spontaneous pneumothorax occurs without a precipitating event in the absence of clinical lung disease.
The causes, clinical manifestations, diagnosis, and management of secondary spontaneous pneumothorax will be reviewed here. Primary spontaneous pneumothorax and catamenial pneumothorax (due to thoracic endometriosis) are discussed separately. (See "Primary spontaneous pneumothorax in adults" and "Thoracic endometriosis".)
Nearly every lung disease can be complicated by secondary spontaneous pneumothorax (SSP), although the most commonly associated diseases are chronic obstructive pulmonary disease, cystic fibrosis, primary or metastatic lung malignancy, and necrotizing pneumonia (eg, bacterial or fungal pneumonia, Pneumocystis jirovecii pneumonia, tuberculosis) [2,3].
Chronic obstructive pulmonary disease — Chronic obstructive pulmonary disease (COPD) is the most common cause of SSP, with 50 to 70 percent of SSP in case series attributed to COPD [2-4]. Rupture of apical blebs is the usual cause. (See "Chronic obstructive pulmonary disease: Definition, clinical manifestations, diagnosis, and staging".)
Severity of COPD correlates with the likelihood of developing SSP. As an example, more than 30 percent of patients with SSP due to COPD have a forced expiratory volume in one second (FEV1) less than one liter and an FEV1 to forced vital capacity (FEV1/FVC) ratio less than 40 percent .