Accumulation of air in the pleural space.
Primary spontaneous pneumothoraces occur in young people without known respiratory illnesses. Patients with pre-existing pulmonary diseases may develop secondary spontaneous pneumothoraces.
A tension pneumothorax is a medical emergency that requires immediate intervention to decompress the involved hemithorax.
Patients with pneumothoraces typically complain of dyspnea and chest pain. In tension pneumothorax, patients are distressed with rapid labored respirations, cyanosis, profuse diaphoresis, and tachycardia.
First-line treatment of pneumothoraces includes observation with supplemental oxygen therapy, percutaneous aspiration of the air in the pleural space, chest-tube thoracostomy, and in some cases video-assisted thoracoscopy or thoracostomy.
Patients who suffer spontaneous pneumothoraces are at risk for recurrence. Pleurodesis (either by mechanical abrasion or by chemical irritation of pleural surfaces) is used to limit the likelihood of recurrence.
Pneumothorax occurs when air gains access to, and accumulates in, the pleural space. 
Division of Pulmonary Diseases and Critical Care Medicine
James H. Quillen College of Medicine
RPB declares that he has no competing interests.
Dr Ryland P. Byrd Jr would like to gratefully acknowledge Dr Thomas M. Roy and Dr Anita Alwani, the previous contributors to this monograph. TMR and AA declare that they have no competing interests.
Professor and Chief Executive Officer of Respiratory Division
Interventional Endoscopy Clinic
University Hospital Brussels
MN declares that he has no competing interests.
Professor of Medicine
Division of Pulmonary Critical Care, Allergy and Sleep Medicine
Medical University of South Carolina
SAS declares that he has no competing interests.
Use of this content is subject to our disclaimer