Editing Pneumothorax (section)

===Primary spontaneous===
Spontaneous pneumothoraces are divided into two types: ''primary'', which occurs in the absence of known lung disease, and ''secondary'', which occurs in someone with underlying lung disease.<ref name="Lyra">{{cite journal | vauthors = Lyra RD | title = Etiology of primary spontaneous pneumothorax | journal = Jornal Brasileiro de Pneumologia | volume = 42 | issue = 3 | pages = 222–226 | date = May–June 2016 | pmid = 27383937 | pmc = 5569604 | doi = 10.1590/S1806-37562015000000230 }}</ref> The cause of primary spontaneous pneumothorax is unknown, but established risk factors include being of the male sex, [[smoking]], and a [[family history (medicine)|family history]] of pneumothorax.<ref name=Rosen2010/> Smoking either [[cannabis]] or [[tobacco]] increases the risk.<ref name=BMJ2014/> The various suspected underlying mechanisms are discussed [[#Mechanism|below]].<ref name=Tschopp/><ref name=Noppen/>