Editing Trachea (section)

==Clinical significance==
===Inflammation and infection===
<!--Intro and causes-->
[[Inflammation]] of the trachea is known as [[tracheitis]], usually due to an infection. It is usually caused by [[viral infection]]s,<ref name="Tristam2019">{{cite book | vauthors = Tristram D |title=Introduction to Clinical Infectious Diseases |chapter=Laryngitis, Tracheitis, Epiglottitis, and Bronchiolitis: Sore Throat, Change in Voice, Feverora Wheezing Infant in Respiratory Distress |date=2019 |publisher=Springer International Publishing |isbn=978-3-319-91080-2 |pages=75–85 |language=en |doi=10.1007/978-3-319-91080-2_7 |s2cid=86826724 }}</ref> with bacterial infections occurring almost entirely in children.<ref name=":1" /> Most commonly, infections occur with inflammation of other parts of the respiratory tract, such as the larynx and bronchi, known as [[croup]],<ref name=":1">{{cite journal | vauthors = Kuo CY, Parikh SR | title = Bacterial tracheitis | journal = Pediatrics in Review | volume = 35 | issue = 11 | pages = 497–499 | date = November 2014 | pmid = 25361911 | doi = 10.1542/pir.35-11-497 | s2cid = 42828725 }}</ref><ref name=Tristam2019/> however bacterial infections may also affect the trachea alone, although they are often associated with a recent viral infection.<ref name=Tristam2019/> Viruses that cause croup are generally the [[parainfluenza virus]]es 1–3, with [[influenza virus]]es A and B also causing croup, but usually causing more serious infections; bacteria may also cause croup and include ''[[Staphylococcus aureus]]'', ''[[Haemophilus influenzae]]'', ''[[Streptococcus pneumoniae]]'' and ''[[Moraxella catarrhalis]]''.<ref name=Tristam2019/> Causes of bacterial infection of the trachea are most commonly ''[[Staphylococcus aureus]]'' and ''[[Streptococcus pneumoniae]]''.<ref>{{cite web | vauthors = Bhatia R |title=Bacterial Tracheitis - Pediatrics |url=https://www.merckmanuals.com/professional/pediatrics/respiratory-disorders-in-young-children/bacterial-tracheitis |website=Merck Manuals Professional Edition |access-date=21 May 2020}}</ref> In patients who are in hospital, additional bacteria that may cause tracheitis include ''[[Escherichia coli]]'', ''[[Klebsiella pneumoniae]]'', and ''[[Pseudomonas aeruginosa]]''.<ref name=Tristam2019/>

<!--Symptoms and management-->
A person affected with tracheitis may start with symptoms that suggest an [[upper respiratory tract infection]] such as a cough, [[sore throat]], or [[Coryza|coryzal symptoms]] such as a [[runny nose]]. Fevers may develop and an affected child may develop [[respiratory distress|difficulty breathing]] and [[sepsis]].<ref name=Tristam2019/><ref name=":1" /> Swelling of the airway can cause narrowing of the airway, causing a hoarse breathing sound called [[stridor]], or even cause complete blockage.<ref name=":1" /> Up to 80% of people affected by bacterial tracheitis require [[intubation|the use of mechanical ventilation]], and treatment may include [[endoscopy]] for the purposes of acquiring microbiological specimens for [[culture and sensitivity]], as well as removal of any dead tissue associated with the infection. Treatment in such situations usually includes [[antibiotic]]s.<ref name=":1" />

===Narrowing===
[[File:Stridor NP OGG 2.ogg|thumb|An example of [[stridor]], which develops when the trachea is narrowed or obstructed]]

A trachea may be [[tracheal stenosis|narrowed or compressed]], usually a result of enlarged nearby lymph nodes; cancers of the trachea or nearby structures; large thyroid [[goitre]]s; or rarely as a result of other processes such as [[aneurysm|unusually swollen blood vessel]]s.<ref name=Davidsons2018 /> Scarring from [[tracheobronchial injury]] or intubation; or inflammation associated with [[granulomatosis with polyangiitis]] may also cause a narrowing of the trachea ([[tracheal stenosis]]).<ref name=Davidsons2018 /> Obstruction invariably causes a harsh breathing sound known as [[stridor]].<ref name=Davidsons2018 /> A camera inserted via the mouth down into the trachea, called [[bronchoscopy]], may be performed to investigate the cause of an obstruction.<ref name=Davidsons2018 /> Management of obstructions depends on the cause. Obstructions as a result of malignancy may be managed with surgery, [[chemotherapy]] or [[radiotherapy]].<ref name=Davidsons2018 />  A stent may be inserted over the obstruction. Benign lesions, such as narrowing resulting from scarring, are likely to be surgically excised.<ref name=Davidsons2018 />

One cause of narrowing is [[tracheomalacia]], which is the tendency for the trachea to collapse when there is increased external pressure, such as when airflow is increased during breathing in or out, due to decreased [[Compliance (physiology)|compliance]].<ref name="Hysinger2016">{{cite journal | vauthors = Hysinger EB, Panitch HB | title = Paediatric Tracheomalacia | journal = Paediatric Respiratory Reviews | volume = 17 | pages = 9–15 | date = January 2016 | pmid = 25962857 | doi = 10.1016/j.prrv.2015.03.002 }}</ref> It can be due to congenital causes, or due to things that develop after birth, such as compression from nearby masses or swelling, or trauma.<ref name="Hysinger2016" /> Congenital tracheomalacia can occur by itself or in association with other abnormalities such as [[bronchomalacia]] or [[laryngomalacia]], and [[tracheoesophageal fistula|abnormal connections between the trachea and the oesophagus]], amongst others.<ref name="Hysinger2016" /> Congenital tracheomalacia often improves without specific intervention; when required, interventions may include [[beta agonist]]s and [[muscarinic agonists]], which enhance the tone of the smooth muscle surrounding the trachea; [[positive pressure ventilation]], or surgery, which may include the placement of a [[stent]], or the removal of the affected part of the trachea.<ref name="Hysinger2016" /> In dogs, particularly miniature dogs and [[toy dogs]], tracheomalacia, as well as [[bronchomalacia]],<ref>{{cite journal | vauthors = Johnson LR, Pollard RE | title = Tracheal collapse and bronchomalacia in dogs: 58 cases (7 /2001-1 /2008) | journal = Journal of Veterinary Internal Medicine | volume = 24 | issue = 2 | pages = 298–305 | date = March 2010 | pmid = 20051001 | doi = 10.1111/j.1939-1676.2009.0451.x | doi-access = free }}</ref> can lead to [[tracheal collapse]], which often presents with a honking goose-like cough.<ref>{{cite journal | vauthors = Maggiore AD | title = Tracheal and airway collapse in dogs | journal = The Veterinary Clinics of North America. Small Animal Practice | volume = 44 | issue = 1 | pages = 117–127 | date = January 2014 | pmid = 24268337 | doi = 10.1016/j.cvsm.2013.09.004 }}</ref>

===Injury===
The trachea may be injured by trauma such as in a vehicle accident, or intentionally by another wilfully inflicting damage for example as practiced in some [[martial arts]].<ref name="Santiago-Rosado">{{cite journal |last1=Santiago-Rosado |first1=Livia M. |last2=Sigmon |first2=David F. |last3=Lewison |first3=Cheryl S. |title=Tracheal Trauma |url=https://www.ncbi.nlm.nih.gov/books/NBK500015/ |website=StatPearls |publisher=StatPearls Publishing |access-date=23 October 2022 |date=2022|pmid=29763191 }}</ref>

===Intubation===
{{Main|Tracheal intubation |Airway management}}

Tracheal intubation refers to the insertion of a [[tracheal tube|tube]] down the trachea.<ref>{{cite web |title=Definition of INTUBATION |url=https://www.merriam-webster.com/dictionary/intubation |website=www.merriam-webster.com |publisher=Merriam Webster |access-date=25 May 2020 |language=en}}</ref> This procedure is commonly performed during [[surgery]], in order to ensure a person receives enough oxygen when sedated. The catheter is connected to a machine that monitors the airflow, oxygenation and several other metrics. This is often one of the responsibilities of an [[anaesthetist]] during surgery.

In an emergency, or when tracheal intubation is deemed impossible, a [[tracheotomy]] is often performed to insert a tube for ventilation, usually when needed for particular types of surgery to be carried out so that the airway can be kept open. The provision of the opening via a tracheotomy is called a [[tracheostomy]].<ref>{{cite web| vauthors = Molnar H |title=Types of Tracheostomy Tubes |date=11 April 2023 |url= http://www.hopkinsmedicine.org/tracheostomy/about/types.html|language=en}}</ref> Another method procedure can be carried, in an emergency situation, and this is a [[cricothyrotomy]].<ref>{{cite web |title=Medical Definition of CRICOTHYROTOMY |url=https://www.merriam-webster.com/medical/cricothyrotomy |website=www.merriam-webster.com |publisher=Merriam Webster |access-date=25 May 2020 |language=en}}</ref>

===Congenital disorders===
[[File:Tracheal diverticulum.png|thumb|Tracheal diverticulum as seen on axial CT imaging]]

[[Tracheal agenesis]]<ref>{{cite journal | vauthors = Chiu T, Cuevas D, Cuevas L, Monteiro C | title = Tracheal agenesis | journal = Southern Medical Journal | volume = 83 | issue = 8 | pages = 925–930 | date = August 1990 | pmid = 2200137 | doi = 10.1097/00007611-199008000-00018 | s2cid = 21260092 }}</ref> is a rare [[birth defect]] in which the trachea fails to develop. The defect is usually fatal though sometimes surgical intervention has been successful.

A [[tracheoesophageal fistula]] is a congenital defect in which the trachea and esophagus are abnormally connected (a {{wt|en|fistula}}). This is because of abnormalities in the separation between the trachea and oesophagus during development.<ref name=Langmans2019 /> This occurs in approximately 1 in 3,000 births, and the most common abnormalities is a separation of the upper and lower ends of the oesophagus, with the upper end finishing in a closed pouch.<ref name=Langmans2019 /> Other abnormalities may be associated with this, including cardiac abnormalities, or [[VACTERL syndrome]].<ref name=Langmans2019 /> Such fistulas may be detected before a baby is born because of [[polyhydramnios|excess amniotic fluid]]; after birth, they are often associated with pneumonitis and pneumonia because of {{wt|en|aspiration}} of food contents.<ref name=Langmans2019 /> Congenital fistulas are often treated by surgical repair.<ref name=Davidsons2018>{{cite book|title=Davidson's principles and practice of medicine| veditors = Ralston SH, Penman ID, Strachan MW, Hobson RP |date=2018 |publisher=Elsevier |isbn=978-0-7020-7028-0 |edition=23rd}}</ref> In adults, fistulas may occur because of erosion into the trachea from nearby malignant tumours, which erode into both the trachea and the oesophagus. Initially, these often result in coughing from swallowed contents of the oesophagus that are aspirated through the trachea, often progressing to fatal pneumonia; there is rarely a curative treatment.<ref name=Davidsons2018 /> A [[tracheo-oesophageal puncture]] is a surgically created hole between the trachea and the esophagus in a person who has had their larynx removed. Air travels upwards from the surgical connection to the upper oesophagus and the pharynx, creating vibrations that create sound that can be used for speech. The purpose of the puncture is to restore a person's ability to speak after the vocal cords have been removed.<ref>{{cite web |title=Evaluation and Treatment for Tracheoesophageal Puncture and Prosthesis: Technical Report |url=https://www.asha.org/policy/TR2004-00138/ |website=American Speech-Language-Hearing Association |publisher=American Speech-Language-Hearing Association (ASHA) |access-date=26 May 2020 |language=en |date=2004}}</ref>

Sometimes as an [[anatomical variation]] one or more of the tracheal rings are formed as complete rings, rather than horseshoe shaped rings. These ''O'' rings are smaller than the normal C-shaped rings and can cause narrowing ({{wt|en|stenosis}}) of the trachea, resulting in breathing difficulties. An operation called a ''slide tracheoplasty'' can open up the rings and rejoin them as wider rings, shortening the length of the trachea.<ref>{{cite web|title=Slide tracheoplasty|url=http://www.cincinnatichildrens.org/health/s/slide-tracheoplasty/|access-date=2 October 2015}}</ref> Slide tracheoplasty is said to be the best option in treating tracheal stenosis.<ref>{{cite journal | vauthors = Xue B, Liang B, Wang S, Zhu L, Lu Z, Xu Z | title = One-stage surgical correction of congenital tracheal stenosis complicated with congenital heart disease in infants and young children | journal = Journal of Cardiac Surgery | volume = 30 | issue = 1 | pages = 97–103 | date = January 2015 | pmid = 25109422 | doi = 10.1111/jocs.12418 | s2cid = 25335958 | doi-access = free }}</ref>

[[Mounier-Kuhn syndrome]] is a rare congenital disorder of an abnormally enlarged trachea, characterised by absent elastic fibres, smooth muscle thinning, and a tendency to get recurrent respiratory tract infections.<ref>{{cite journal | vauthors = Menon B, Aggarwal B, Iqbal A | title = Mounier-Kuhn syndrome: report of 8 cases of tracheobronchomegaly with associated complications | journal = Southern Medical Journal | volume = 101 | issue = 1 | pages = 83–87 | date = January 2008 | pmid = 18176298 | doi = 10.1097/SMJ.0b013e31815d4259 }}</ref>

===Replacement===
From 2008, operations have experimentally replaced tracheas, with those grown from [[stem cell]]s, or with synthetic substitutes, however this is regarded as experimental and there is no standardised method.<ref name="Tracheal replacement">{{cite journal | vauthors = Delaere P, Van Raemdonck D | title = Tracheal replacement | journal = Journal of Thoracic Disease | volume = 8 | issue = Suppl 2 | pages = S186–S196 | date = March 2016 | pmid = 26981270 | pmc = 4775267 | doi = 10.3978/j.issn.2072-1439.2016.01.85 }}</ref> Difficulties with ensuring adequate blood supply to the replaced trachea is considered a major challenge to any replacement. Additionally, no evidence has been found to support the placement of stem cells taken from [[bone marrow]] on the trachea as a way of stimulating tissue regeneration, and such a method remains hypothetical.<ref name="Tracheal replacement" />

In January 2021, surgeons at [[Mount Sinai Hospital (Manhattan)|Mount Sinai Hospital]] in New York performed the first complete trachea transplantation. The 18-hour procedure included harvesting a trachea from a donor and implanting it in the patient, connecting numerous veins and arteries to provide sufficient blood flow to the organ.<ref>{{cite news|url=https://www.npr.org/sections/health-shots/2021/04/06/981735718/woman-gets-new-windpipe-in-groundbreaking-transplant-surgery| title=Woman Gets New Windpipe In Groundbreaking Transplant Surgery| date=6 April 2021| access-date=6 April 2021| vauthors = Harris R | work=NPR}}</ref>