Editing Pneumothorax (section)

==Cause==
[[File:Pneumot rax bullae.JPG|thumb|upright=1.2|alt=A schematic drawing showing a bulla and a bleb, two lung abnormalities that can lead to pneumothorax |A schematic drawing of a bulla and a bleb, two lung abnormalities that may rupture and lead to pneumothorax]]

===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/>

===Secondary spontaneous===
Secondary spontaneous pneumothorax occurs in the setting of a variety of lung diseases. The most common is [[chronic obstructive pulmonary disease]] (COPD), which accounts for approximately 70% of cases.<ref name=Rosen2010/> The following known lung diseases may significantly increase the risk for pneumothorax.

{| class="wikitable"
! scope="col" | Type
! scope="col" | Causes
|-
! scope="row" | Diseases of the airways<ref name=Tschopp/>
| COPD (especially when [[bullous emphysema]] is present), [[asthma|acute severe asthma]], [[cystic fibrosis]]
|-
! scope="row" | Infections of the lung<ref name=Tschopp/>
| [[Pneumocystis pneumonia]] (PCP), [[tuberculosis]], [[pneumonia|necrotizing pneumonia]]
|-
! scope="row" | [[Interstitial lung disease]]<ref name=Tschopp/>
| [[Sarcoidosis]], [[idiopathic pulmonary fibrosis]], [[Langerhans cell histiocytosis|histiocytosis X]], [[lymphangioleiomyomatosis]] (LAM)
|-
! scope="row" | [[Connective tissue disease]]s<ref name=Tschopp/>
| [[Rheumatoid arthritis]], [[ankylosing spondylitis]], [[polymyositis]] and [[dermatomyositis]], [[systemic sclerosis]], [[Marfan's syndrome]] and [[Ehlers–Danlos syndrome]]
|-
! scope="row" | [[Cancer]]<ref name=Tschopp/>
| [[Lung cancer]], [[sarcoma]]s involving the lung
|-
! scope="row" | Miscellaneous<ref name=Noppen/>
| [[Catamenial pneumothorax]] (associated with the [[menstrual cycle]] and related to [[endometriosis]] in the chest)
|}

In children, additional causes include [[measles]], [[echinococcosis]], inhalation of a [[foreign body]], and certain [[congenital malformation]]s ([[congenital pulmonary airway malformation]] and [[Pneumatosis#Congenital lobar emphysema|congenital lobar emphysema]]).<ref name="Robinson">{{cite journal | vauthors = Robinson PD, Cooper P, Ranganathan SC | title = Evidence-based management of paediatric primary spontaneous pneumothorax | journal = Paediatric Respiratory Reviews | volume = 10 | issue = 3 | pages = 110–7; quiz 117 | date = September 2009 | pmid = 19651381 | doi = 10.1016/j.prrv.2008.12.003 }}</ref>

11.5% of people with a spontaneous pneumothorax have a family member who has previously experienced a pneumothorax. Several hereditary conditions – [[Marfan syndrome]], [[homocystinuria]], [[Ehlers–Danlos syndromes]], [[alpha 1-antitrypsin deficiency]] (which leads to [[Pneumatosis#Lungs|emphysema]]), and [[Birt–Hogg–Dubé syndrome]] – have all been linked to familial pneumothorax.<ref name="Chiu">{{cite journal | vauthors = Chiu HT, Garcia CK | title = Familial spontaneous pneumothorax | journal = Current Opinion in Pulmonary Medicine | volume = 12 | issue = 4 | pages = 268–272 | date = July 2006 | pmid = 16825879 | doi = 10.1097/01.mcp.0000230630.73139.f0 | s2cid = 45908721 }}</ref> Generally, these conditions cause other signs and symptoms as well, and pneumothorax is not usually the primary finding.<ref name=Chiu/> Birt–Hogg–Dubé syndrome is caused by mutations in the ''FLCN'' [[gene]] (located at [[chromosome 17]]p11.2), which encodes a protein named [[folliculin]].<ref name=Robinson/><ref name=Chiu/> ''FLCN'' mutations and lung lesions have also been identified in familial cases of pneumothorax where other features of Birt–Hogg–Dubé syndrome are absent.<ref name=Robinson/> In addition to the genetic associations, the [[human leukocyte antigen|HLA]] [[haplotype]] A<sub>2</sub>B<sub>40</sub> is also a genetic predisposition to PSP.<ref name="Fishman1520">{{Cite book |vauthors=Levine DJ, Sako EY, Peters J | title=Fishman's Pulmonary Diseases and Disorders |url=https://archive.org/details/fishmanspulmonar00afis |url-access=limited | publisher=McGraw-Hill | year=2008 | page=[https://archive.org/details/fishmanspulmonar00afis/page/n1551 1520] | edition=4th | isbn=978-0-07-145739-2 }}</ref><ref name="Light307">{{Cite book | vauthors = Light RW | title=Pleural diseases | publisher=Lippincott Williams & Wilkins | year=2007 | page=307 | edition=5th | isbn=978-0-7817-6957-0 }}</ref>

===Traumatic===
A traumatic pneumothorax may result from either [[blunt trauma]] or [[Penetrating trauma|penetrating injury]] to the chest wall.<ref name=Noppen/> The most common mechanism is the penetration of sharp bony points at a new [[rib fracture]], which damages lung tissue.<ref name=Rosen2010>{{cite book |title=Rosen's emergency medicine: concepts and clinical practice |edition=7th | vauthors = Marx J |year=2010 |publisher=Mosby/Elsevier |location=Philadelphia, PA |isbn=978-0-323-05472-0 |pages=393–96}}</ref> Traumatic pneumothorax may also be observed in those [[blast injury|exposed to blasts]], even when there is no apparent injury to the chest.<ref name=Wolf2009/>

Traumatic pneumothoraces may be classified as "open" or "closed". In an open pneumothorax, there is a passage from the external environment into the pleural space through the chest wall. When air is drawn into the pleural space through this passageway, it is known as a "sucking chest wound". A closed pneumothorax is when the chest wall remains intact.<ref name="Rathert">{{cite web|vauthors = ((Nicholas Rathert, W. Scott Gilmore, MD, EMT-P))|title=Treating Sucking Chest Wounds and Other Traumatic Chest Injuries|url=http://www.jems.com/articles/print/volume-38/issue-8/patient-care/treating-sucking-chest-wounds-and-other.html|website=www.jems.com|publisher=Journal of Emergency Medical Services|access-date=28 September 2017|archive-url=https://web.archive.org/web/20150408043836/http://www.jems.com/articles/print/volume-38/issue-8/patient-care/treating-sucking-chest-wounds-and-other.html|archive-date=8 April 2015|date=19 July 2013|url-status=dead}}</ref>

Pneumothorax was reported as an adverse event caused by misplaced [[Nasogastric intubation|nasogastric feeding tubes]]. [[Avanos Medical]]'s feeding tube placement system, the CORTRAK* 2 EAS, was recalled in May 2022 by the [[Food and Drug Administration|FDA]] due to adverse events reported, including pneumothorax, leading to 60 injuries and 23 people dying as communicated by the FDA.<ref>{{cite web |title=Avanos Medical Recalls Cortrak*2 Enteral Access System for Risk of Misplaced Enteral Tubes Could Cause Patient Harm |url=https://www.fda.gov/medical-devices/medical-device-recalls/avanos-medical-recalls-cortrak2-enteral-access-system-risk-misplaced-enteral-tubes-could-cause |archive-url=https://web.archive.org/web/20220513213417/https://www.fda.gov/medical-devices/medical-device-recalls/avanos-medical-recalls-cortrak2-enteral-access-system-risk-misplaced-enteral-tubes-could-cause |url-status=dead |archive-date=13 May 2022 |website=FDA |date=16 May 2022 |publisher=Admin |access-date=16 May 2022}}</ref>

Medical procedures, such as inserting a [[central venous catheter]] into one of the chest veins or taking [[biopsy]] samples from lung tissue, may also lead to pneumothorax. The administration of [[positive pressure ventilation]], either [[mechanical ventilation]] or [[non-invasive ventilation]], can result in [[barotrauma]] (pressure-related injury) leading to a pneumothorax.<ref name=Noppen/>

[[Underwater diving|Divers]] who breathe from an underwater apparatus are supplied with breathing gas at [[ambient pressure]], which results in their lungs containing gas at higher than atmospheric pressure. Divers breathing compressed air (such as when [[scuba diving]]) may develop a pneumothorax as a result of [[barotrauma]] from ascending just {{convert|1|m|ft|0}} while breath-holding with their lungs fully inflated.<ref name=BE2003>{{cite book |title=Bennett and Elliott's physiology and medicine of diving |edition=5th Rev |veditors=Brubakk AO, Neuman TS |year=2003 |publisher=Saunders |location=United States |isbn=978-0-7020-2571-6 | vauthors = Neuman TS |chapter=Arterial gas embolism and pulmonary barotrauma |pages=558–61}}</ref> An additional problem in these cases is that those with other features of [[decompression sickness]] are typically treated in a [[diving chamber]] with [[hyperbaric medicine|hyperbaric therapy]]; this can lead to a small pneumothorax rapidly enlarging and causing features of tension.<ref name=BE2003/>

=== Newborn infants ===
Pneumothorax is more common in neonates than in any other age group. The incidence of symptomatic neonatal is estimated to be around 1-3 per 1000 live births. Prematurity, low birth weight and asphyxia are the major risk factors, and a majority of newborn infant cases occur during the first 72 hours of life.<ref>{{Cite journal |last1=Vibede |first1=Louise |last2=Vibede |first2=Emil |last3=Bendtsen |first3=Mette |last4=Pedersen |first4=Lia |last5=Ebbesen |first5=Finn |date=2016-12-24 |title=Neonatal Pneumothorax: A Descriptive Regional Danish Study |url=http://dx.doi.org/10.1159/000453029 |journal=Neonatology |volume=111 |issue=4 |pages=303–308 |doi=10.1159/000453029 |pmid=28013308 |s2cid=4314067 |issn=1661-7800|url-access=subscription }}</ref><ref name=":0">{{cite journal | vauthors = Bruschettini M, Romantsik O, Zappettini S, O'Donnell CP, Calevo MG | title = Needle aspiration versus intercostal tube drainage for pneumothorax in the newborn | journal = The Cochrane Database of Systematic Reviews | volume = 2019 | pages = CD011724 | date = February 2019 | issue = 2 | pmid = 30707441 | pmc = 6357997 | doi = 10.1002/14651858.CD011724.pub3 }}</ref><ref name="doi.org"/>

=== Artificial Pneumothorax ===
In the late 1800s and early 1900s, physicians namely [[Carlo Forlanini]], a physician from Italy, began experimenting with intentionally collapsing the lungs of patients infected with [[tuberculosis]].<ref name=":1">{{Cite journal |last=Sakula |first=A |date=1983 |title=Carlo Forlanini, inventor of artificial pneumothorax for treatment of pulmonary tuberculosis. |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC459551/?page=5 |journal=Thorax |volume=38 |issue=5 |pages=326–332. |doi=10.1136/thx.38.5.326 |pmid=6348993 |via=PubMed|pmc=459551 }}</ref> The goal of treatment was to deprive the oxygen dependent mycobacterium of the resources it requires to multiply and spread.<ref name=":1" /> Although this method fell out of common practice following the advent of pharmaceutical advancements, some research shows that in cases where medications are not effective, AP has successful results.<ref name=":2">{{Cite journal |last=Motus |first=I. Y. |last2=Skorniakov |first2=S. N. |last3=Sokolov |first3=V. A. |last4=Egorov |first4=E. A. |last5=Kildyusheva |first5=E. I. |last6=Savel'ev |first6=A. V. |last7=Zaletaeva |first7=G. E. |date=2006-05-01 |title=Reviving an old idea: can artificial pneumothorax play a role in the modern management of tuberculosis? |url=https://www.ingentaconnect.com/content/iuatld/ijtld/2006/00000010/00000005/art00017 |journal=The International Journal of Tuberculosis and Lung Disease |volume=10 |issue=5 |pages=571–577}}</ref> However, the same complications that arise with other mechanisms may still apply, leading to questions of risk vs. benefit.<ref name=":2" />