Editing Pneumothorax (section)

==Signs and symptoms==
A primary spontaneous pneumothorax (PSP) tends to occur in a young adult without underlying lung problems, and usually causes limited symptoms. Chest pain and sometimes mild breathlessness are the usual predominant presenting features.<ref name="Tschopp">{{cite journal | vauthors = Tschopp JM, Rami-Porta R, Noppen M, Astoul P | title = Management of spontaneous pneumothorax: state of the art | journal = The European Respiratory Journal | volume = 28 | issue = 3 | pages = 637–650 | date = September 2006 | pmid = 16946095 | doi = 10.1183/09031936.06.00014206 | doi-access = free }}</ref><ref name="Noppen">{{cite journal | vauthors = Noppen M, De Keukeleire T | title = Pneumothorax | journal = Respiration; International Review of Thoracic Diseases | volume = 76 | issue = 2 | pages = 121–127 | year = 2008 | pmid = 18708734 | doi = 10.1159/000135932 | doi-access = free }}</ref> In newborns [[tachypnea]], [[cyanosis]] and grunting are the most common presenting symptoms.<ref name="doi.org">{{Cite journal |last1=Andersson |first1=J. |last2=Magnuson |first2=A. |last3=Ohlin |first3=A. |date=2021-02-03 |title=Neonatal pneumothorax: symptoms, signs and timing of onset in the post-surfactant era |journal=The Journal of Maternal-Fetal & Neonatal Medicine |volume=35 |issue=25 |pages=5438–5442 |doi=10.1080/14767058.2021.1882981 |issn=1476-7058 |pmid=33535849|s2cid=231805530 |doi-access=free }}</ref> People who are affected by a PSP are often unaware of the potential danger and may wait several days before seeking medical attention.<ref name="BTS">{{cite journal | vauthors = MacDuff A, Arnold A, Harvey J | title = Management of spontaneous pneumothorax: British Thoracic Society Pleural Disease Guideline 2010 | journal = Thorax | volume = 65 | issue = 8 Suppl 2 | pages = ii18–ii31 | date = August 2010 | pmid = 20696690 | doi = 10.1136/thx.2010.136986 | title-link = British Thoracic Society | collaboration = BTS Pleural Disease Guideline Group | doi-access = free }}</ref> PSPs more commonly occur during changes in [[atmospheric pressure]], explaining to some extent why episodes of pneumothorax may happen in clusters.<ref name=Noppen/> It is rare for a PSP to cause a tension pneumothorax.<ref name=Tschopp/>

Secondary spontaneous pneumothoraces (SSPs), by definition, occur in individuals with significant underlying lung disease. Symptoms in SSPs tend to be more severe than in PSPs, as the unaffected lungs are generally unable to replace the loss of function in the affected lungs. [[Hypoxemia]] (decreased blood-oxygen levels) is usually present and may be observed as [[cyanosis]] (blue discoloration of the lips and skin). [[Hypercapnia]] (accumulation of carbon dioxide in the blood) is sometimes encountered; this may cause [[mental confusion|confusion]] and – if very severe – may result in [[coma]]s. The sudden onset of breathlessness in someone with [[chronic obstructive pulmonary disease]] (COPD), [[cystic fibrosis]], or other serious lung diseases should therefore prompt investigations to identify the possibility of a pneumothorax.<ref name=Tschopp/><ref name=BTS/>

Traumatic pneumothorax most commonly occurs when the chest wall is pierced, such as when a [[stab wound]] or [[gunshot wound]] allows air to enter the [[pleural cavity|pleural space]], or because some other mechanical injury to the lung compromises the integrity of the involved structures. Traumatic pneumothoraces have been found to occur in up to half of all cases of chest trauma, with only [[rib fracture]]s being more common in this group. The pneumothorax can be occult (not readily apparent) in half of these cases, but may enlarge – particularly if [[mechanical ventilation]] is required.<ref name=Noppen/> They are also encountered in people already receiving mechanical ventilation for some other reason.<ref name=Noppen/>

Upon [[physical examination]], [[respiratory sounds|breath sounds]] (heard with a [[stethoscope]]) may be diminished on the affected side, partly because air in the pleural space dampens the transmission of sound. Measures of the conduction of vocal vibrations to the surface of the chest may be altered. [[Percussion (medicine)|Percussion]] of the chest may be perceived as hyperresonant (like a booming drum), and [[vocal resonation|vocal resonance]] and [[fremitus|tactile fremitus]] can both be noticeably decreased. Importantly, the volume of the pneumothorax may not be well [[correlation|correlated]] with the intensity of the symptoms experienced by the victim,<ref name=BTS/> and physical signs may not be apparent if the pneumothorax is relatively small.<ref name=Noppen/><ref name=BTS/>

===Tension pneumothorax===
Tension pneumothorax is generally considered to be present when a pneumothorax (primary spontaneous, secondary spontaneous, or traumatic) leads to significant impairment of [[Respiration (physiology)|respiration]] and/or [[perfusion|blood circulation]].<ref name="Leigh-Smith">{{cite journal | vauthors = Leigh-Smith S, Harris T | title = Tension pneumothorax--time for a re-think? | journal = Emergency Medicine Journal | volume = 22 | issue = 1 | pages = 8–16 | date = January 2005 | pmid = 15611534 | pmc = 1726546 | doi = 10.1136/emj.2003.010421 }}</ref> This causes a type of circulatory shock, called [[obstructive shock]]. Tension pneumothorax tends to occur in clinical situations such as ventilation, resuscitation, trauma, or in people with lung disease.<ref name=BTS /> It is a [[medical emergency]] and may require immediate treatment without further investigations (see [[#Treatment|Treatment section]]).<ref name=BTS/><ref name=Leigh-Smith/>

The most common findings in people with tension pneumothorax are chest pain and respiratory distress, often with an increased [[heart rate]] ([[tachycardia]]) and rapid breathing ([[tachypnea]]) in the initial stages. Other findings may include quieter breath sounds on one side of the chest, low [[Oxygenation (medical)|oxygen levels]] and [[blood pressure]], and displacement of the [[human trachea|trachea]] away from the affected side. Rarely, there may be [[cyanosis]], [[altered level of consciousness]], a hyperresonant percussion note on examination of the affected side with reduced expansion and decreased movement, pain in the [[epigastrium]] (upper abdomen), displacement of the [[apex beat]] (heart impulse), and resonant sound when tapping the [[sternum]].<ref name=Leigh-Smith/>

Tension pneumothorax may also occur in someone who is receiving mechanical ventilation, in which case it may be difficult to spot as the person is typically receiving [[sedation]]; it is often noted because of a sudden deterioration in condition.<ref name=Leigh-Smith/> Recent studies have shown that the development of tension features may not always be as rapid as previously thought. Deviation of the trachea to one side and the presence of raised [[jugular venous pressure]] (distended neck veins) are not reliable as clinical signs.<ref name=Leigh-Smith/>