View source for Emphysema

{{See|Chronic obstructive pulmonary disease}}
{{Infobox medical condition (new)
| name          = Emphysema
| image         = Emphysema, centrilobular (4563270814).jpg
| caption       = Advanced [[centrilobular emphysema]] showing total [[Pulmonary lobule|lobule]] involvement on the left side
| field         = [[Pulmonology]]
| synonyms      =
| symptoms      = [[Shortness of breath]], chronic [[cough]]<ref name='CKSNice'>{{cite web |title=Chronic obstructive pulmonary disease |url=https://cks.nice.org.uk/topics/chronic-obstructive-pulmonary-disease/ |website=nice.org.uk |publisher=[[National Institute for Health and Care Excellence]] |access-date=5 July 2021}}</ref>
| complications =
| onset         = Over 35 years old<ref name='CKSNice' />
| duration      = Long term<ref name='CKSNice' />
| causes        = [[Tobacco smoking]],<ref name="IJERPH 2009">{{cite journal |last=Laniado-Laborín |first=Rafael |date=January 2009 |title=Smoking and Chronic Obstructive Pulmonary Disease (COPD). Parallel Epidemics of the 21st Century |journal=[[International Journal of Environmental Research and Public Health]] |publisher=[[MDPI]] |volume=6 |issue=1: ''Smoking and Tobacco Control'' |doi=10.3390/ijerph6010209 |pages=209–224 |doi-access=free |issn=1660-4601 |pmc=2672326 |pmid=19440278 |s2cid=19615031 }}</ref> [[air pollution]], [[genetics]]
| risks         =
| diagnosis     = [[Spirometry]]{{sfn|Gold Report 2021|pp=20-23|loc=Chapter 2: Diagnosis and initial assessment}}   
| differential  = [[Asthma]], [[congestive heart failure]], [[bronchiectasis]], [[tuberculosis]], [[obliterative bronchiolitis]], [[diffuse panbronchiolitis]]{{sfn|Gold Report 2021|pp=33–35|loc=Chapter 2: Diagnosis and initial assessment}}
| prevention    = [[Smoking cessation|Stopping smoking]], improving indoor and outdoor [[air quality]], [[tobacco control]] measures{{sfn|Gold Report 2021|pp=40–46|loc=Chapter 3: Evidence supporting prevention and maintenance therapy}}
| treatment     = [[Pulmonary rehabilitation]], [[oxygen therapy|long-term oxygen therapy]],  [[lung volume reduction]]{{sfn|Gold Report 2021|pp=40–46|loc=Chapter 3: Evidence supporting prevention and maintenance therapy}}
| medication    = Inhaled [[bronchodilator]]s and [[corticosteroid]]s{{sfn|Gold Report 2021|pp=40–46|loc=Chapter 3: Evidence supporting prevention and maintenance therapy}}
| prognosis     =
| frequency     =
| deaths        =
| alt           =
}}

'''Emphysema''', or '''pulmonary emphysema''', is a [[Lower respiratory tract|lower respiratory tract disease]],<ref name='ICD11'>{{cite web |title=ICD-11 - ICD-11 for Mortality and Morbidity Statistics |url=https://icd.who.int/browse11/l-m/en#/http%3a%2f%2fid.who.int%2ficd%2fentity%2f1948124976 |website=icd.who.int |access-date=9 August 2021}}</ref> characterised by air-filled spaces ([[Pneumatosis|pneumatoses]]) in the [[lungs]], that can vary in size and may be very large. The spaces are caused by the breakdown of the [[Alveolar wall|walls]] of the [[Pulmonary alveolus|alveoli]] and they replace the spongy [[Parenchyma#Lungs|lung parenchyma]]. This reduces the total alveolar surface available for [[gas exchange]] leading to a reduction in oxygen supply for the blood.<ref name='Saladin'>{{cite book |last1=Saladin |first1=K |title=Human anatomy |date=2011 |publisher=McGraw-Hill |isbn=9780071222075 |page=650 |edition=3rd}}</ref> Emphysema usually affects the [[middle age]]d or [[Old age|older]] population because it takes time to develop with the effects of [[tobacco smoking]],<ref name="IJERPH 2009"/> and other risk factors. [[Alpha-1 antitrypsin deficiency]] is a genetic risk factor that may lead to the condition presenting earlier.<ref name='Murphy'>{{Cite web|url=https://radiopaedia.org/articles/pulmonary-emphysema?lang=gb|title=Pulmonary emphysema|last1=Murphy|first1=Andrew|last2=Danaher|first2=Luke|website=radiopaedia.org|access-date=16 August 2019}}</ref>

When associated with significant airflow limitation, emphysema is a [[Chronic obstructive pulmonary disease#Subtypes|major subtype of chronic obstructive pulmonary disease]] ([[Chronic obstructive pulmonary disease|COPD]]), a progressive lung disease characterized by long-term breathing problems and poor airflow.<ref name='GOLD2017Chp1'>{{cite book | last=Algusti | first=Alvar G.|display-authors=etal| title=Global Strategy for the Diagnosis, Management and Prevention of COPD |year=2017 | publisher=[[Global Initiative for Chronic Obstructive Lung Disease]] (GOLD) | pages=6–17 | chapter=Definition and Overview | chapter-url=http://goldcopd.org/download/326/}}</ref><!--p. 6--><ref name='Roversi2017'>{{cite journal | last1=Roversi| first1=Sara| last2=Corbetta| first2=Lorenzo| last3=Clini|first3=Enrico |title=GOLD 2017 recommendations for COPD patients: toward a more personalized approach|date=5 May 2017 |journal=COPD Research and Practice |volume=3 |doi=10.1186/s40749-017-0024-y|url=https://flore.unifi.it/bitstream/2158/1119012/1/s40749-017-0024-y.pdf|doi-access=free}}</ref> Without COPD, the finding of emphysema on [[Chest CT#Lungs|a CT lung scan]] still confers a higher mortality risk in [[tobacco smokers]].<ref>{{cite web|url=https://www.medscape.com/viewarticle/836650|title=Emphysema on CT Without COPD Predicts Higher Mortality Risk|author=Diedtra Henderson|date=2014-12-16|website=[[Medscape]]}}</ref> In 2016 in the United States there were 6,977 deaths from emphysema – 2.2 per 100,000 of the population.<ref name='cdc'>{{cite web |title=FastStats - Chronic Lower Respiratory Disease |url=https://www.cdc.gov/nchs/fastats/copd.htm |website=www.cdc.gov |access-date=30 May 2019 |date=23 May 2019}}</ref> Globally it accounts for 5% of all deaths.<ref name='Martini'>{{cite journal |last1=Martini |first1=K. |last2=Frauenfelder |first2=T. |title=Advances in imaging for lung emphysema. |journal=Annals of Translational Medicine |date=November 2020 |volume=8 |issue=21 |pages=1467 |doi=10.21037/atm.2020.04.44 |pmid=33313212|pmc=7723580 }}</ref> A 2018 review of work on the effects of tobacco and cannabis smoking found that a possibly cumulative toxic effect could be a risk factor for developing emphysema, and [[spontaneous pneumothorax]].<ref name='Underner'>{{cite journal |last1=Underner |first1=M |last2=Urban |first2=T |last3=Perriot |first3=J |display-authors=etal|title=REVUE GÉNÉRALE - Pneumothorax spontané et emphysème pulmonaire chez les consommateurs de cannabis|language=fr|trans-title=Spontaneous pneumothorax and lung emphysema in cannabis users|journal=Revue de pneumologie clinique |date=December 2018 |volume=74 |issue=6 |pages=400–415 |doi=10.1016/j.pneumo.2018.06.003 |pmid=30420278|s2cid=59233744 }}</ref><ref>{{cite web | last=Coffey | first=Donavyn | title=Buzz Kill: Lung Damage Looks Worse in Pot Smokers | website=Medscape | date=15 November 2022 | url=https://www.medscape.com/viewarticle/984059}}</ref>

There are four types of emphysema, three of which are related to the anatomy of the [[pulmonary lobule|lobules of the lung]] – centrilobular or centriacinar, panlobular or panacinar, and paraseptal or distal acinar emphysema, and are not associated with [[Pulmonary fibrosis|fibrosis]] (scarring).{{sfn|Kumar|2018|pp=498-501}} The fourth type is known as paracicatricial emphysema or irregular emphysema that  involves the [[Lung#Respiratory zone|acinus]] irregularly and is associated with fibrosis.{{sfn|Kumar|2018|pp=498-501}} Though the different types can be seen on [[Medical imaging|imaging]] they are not well-defined clinically.<ref name='Smith' /> There are also a number of associated conditions including [[bullous emphysema]], [[focal emphysema]], and [[Ritalin lung]]. Only the first two types of emphysema – centrilobular and panlobular – are associated with significant airflow obstruction, with that of centrilobular emphysema around 20 times more common than panlobular. Centrilobular emphysema is the only type associated with [[tobacco smoking|smoking]].{{sfn|Kumar|2018|pp=498-501}}

[[Osteoporosis]] is often a [[comorbidity]] of emphysema. The use of [[systemic administration|systemic]] [[corticosteroids]] for treating exacerbations is a significant risk factor for osteoporosis, and their repeated use is recommended against.<ref name='Gold'>{{Cite web|url=https://goldcopd.org/wp-content/uploads/2018/11/GOLD-2019-v1.7-FINAL-14Nov2018-WMS.pdf|title=COPD and comorbidities|page=133|access-date=24 September 2019}}</ref>

==Signs and symptoms==
[[File:Blausen 0343 Emphysema.png|thumb|300px|Diagram of aveoli with emphysema]]
Emphysema is a respiratory disease of the [[lower respiratory tract]].<ref name='ICD11'/> It is commonly caused by [[tobacco smoking]] but a significant number of people are affected who either do not smoke, or have never smoked.<ref name='Martini'/> The presence of emphysema is a clear risk factor for the development of [[lung cancer]], made stronger in those who smoke.<ref name='GOLD2021'>{{cite book |title=Global Strategy for Prevention, Diagnosis and Management of COPD: 2021 Report |date=25 November 2020|page=123|url=https://goldcopd.org/wp-content/uploads/2020/11/GOLD-REPORT-2021-v1.1-25Nov20_WMV.pdf |access-date=3 October 2021}}</ref>

Early symptoms of emphysema may vary from person to person. Symptoms can include a cough (with or without sputum), wheezing, a fast breathing rate, breathlessness on exertion, and a feeling of tightness in the chest. There may be frequent cold or flu infections.<ref name='medline'>{{cite web |title=Emphysema |url=https://medlineplus.gov/emphysema.html |access-date=3 October 2021}}</ref> Other symptoms may include anxiety, depression, fatigue, sleep problems and weight loss. Since these symptoms could also relate to other lung conditions or other health problems, emphysema is often under diagnosed.<ref name='Hopkins'>{{cite web |title=Pulmonary Emphysema |url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/pulmonary-emphysema |website=www.hopkinsmedicine.org |date=19 November 2019 |access-date=3 October 2021}}</ref> The shortness of breath caused by emphysema can increase over time and develop into [[chronic obstructive pulmonary disease]].

A sign of emphysema in smokers is the finding of a higher number of [[alveolar macrophage]]s sampled from the [[bronchoalveolar lavage]] (BAL) in the lungs. The number can be four to six times greater in those who smoke than in non-smokers.<ref name='Naeem'>{{cite journal |last1=Naeem |first1=Ahmed |last2=Rai |first2=Sachchida N. |last3=Pierre |first3=Louisdon |title=Histology, Alveolar Macrophages |url=https://www.ncbi.nlm.nih.gov/books/NBK513313/ |website=StatPearls |publisher=StatPearls Publishing |access-date=22 October 2021 |date=2021|pmid=30020685 }}</ref>

==Types==
There are four main types of emphysema, three of which are related to the anatomy of the [[pulmonary lobule|lobules of the lung]] – centrilobular or centriacinar, panlobular or panacinar, and paraseptal or distal acinar and are not associated with [[Pulmonary fibrosis|fibrosis]] (scarring).{{sfn|Kumar|2018|pp=498-501}} Although fibrosis is not a normal feature of these subtypes, repair strategies in end-stage emphysema may lead to [[pulmonary fibrosis]].<ref name='Martini'/> The fourth subtype is known as paracicatricial emphysema or irregular emphysema, involves the acinus irregularly and is associated with fibrosis.{{sfn|Kumar|2018|pp=498-501}}

Only the first two types of emphysema – centrilobular, and panlobular are associated with significant airflow obstruction, with that of centrilobular emphysema around 20 times more common than panlobular.{{sfn|Kumar|2018|pp=498-501}} The subtypes can be  seen on [[Medical imaging|imaging]] but are not well-defined clinically.<ref name='Smith' />
There are also a number of associated conditions including bullous emphysema, focal emphysema, and Ritalin lung.

===Centrilobular===
Centrilobular emphysema, also called '''centriacinar emphysema''', affects the centre of a [[pulmonary lobule]] (centrilobular) in the lung, the area around the terminal bronchiole, and the first respiratory bronchiole, and can be seen on imaging as an area around the tip of the visible pulmonary artery. Centrilobular emphysema is the most common type usually associated with smoking, and with [[Bronchitis#Chronic bronchitis|chronic bronchitis]].{{sfn|Kumar|2018|pp=498-501}} The disease progresses from the centrilobular portion, leaving the lung parenchyma in the surrounding (perilobular) region preserved.<ref name='Takahashi'>{{Cite journal|last1=Takahashi|first1=M|last2=Fukuoka|first2=J|date=2008|title=Imaging of pulmonary emphysema: a pictorial review.|journal= International Journal of Chronic Obstructive Pulmonary Disease|volume=3|issue=2|pages=193–204|pmid=18686729|pmc=2629965|doi=10.2147/COPD.S2639}}</ref> Usually the upper lobes of the lungs are affected.{{sfn|Kumar|2018|pp=498-501}}

===Panlobular===
Panlobular emphysema, also called '''panacinar emphysema''' affects all of the alveoli in a lobule and can involve the whole lung or mainly the lower lobes.<ref name='Smith'/><ref name='Weerakkody'>{{Cite encyclopedia |title=Panlobular emphysema |encyclopedia=[[Radiopaedia]] |url=https://radiopaedia.org/articles/panlobular-emphysema?lang=us |last=Weerakkody |first=Yuranga |year=2013 |doi=10.53347/rid-21965 |s2cid=239605521 |access-date=22 May 2019}}</ref> This type of emphysema is associated with [[alpha-1 antitrypsin deficiency]] (A1AD or AATD), and [[Ritalin lung]],<ref name='Weerakkody' /> and is not related to smoking.<ref name='Smith' />

====Complications====
Likely complications of centrilobular, and panlobular emphysema, some of which are life-threatening, include: [[respiratory failure]], [[pneumonia]], [[Acute exacerbation of chronic obstructive pulmonary disease|respiratory infections]], [[pneumothorax]], [[interstitial lung disease|interstitial emphysema]], [[pulmonary heart disease]], and [[respiratory acidosis]].<ref name='Pahal'>{{cite journal |last1=Pahal |first1=Parul |last2=Avula |first2=Akshay |last3=Sharma |first3=Sandeep |title=Emphysema |url=https://www.ncbi.nlm.nih.gov/books/NBK482217/ |website=StatPearls |publisher=StatPearls Publishing |access-date=26 August 2021 |date=2021|pmid=29489292 }}</ref>

===Paraseptal===
Paraseptal emphysema, also called '''distal acinar emphysema''' relates to emphysematous change next to a [[pleura]]l surface, or to a [[Lung#Right lung|fissure]].<ref name='Smith'>{{Cite journal|last=Smith|first=B|date=January 2014|title=Pulmonary emphysema subtypes on computed tomography: the MESA COPD study.|journal=Am J Med|volume=127|issue=1|pages=94.e7–23|pmid=24384106|pmc=3882898|doi=10.1016/j.amjmed.2013.09.020}}</ref><ref name='Chest'>{{Cite web|url=http://www.radiologyassistant.nl/en/p42d94cd0c326b/lung-hrct-basic-interpretation.html#i458119136dc3b|title=Chest|website=Radiology assistant|access-date=20 June 2019}}</ref> The cystic spaces known as [[Focal lung pneumatosis|blebs or bullae]] that form in paraseptal emphysema typically occur in just one layer beneath the pleura. This distinguishes it from the [[honeycombing]] of small cystic spaces seen in [[fibrosis]] that typically occurs in layers.<ref name='Chest'/> This type of emphysema is not associated with airflow obstruction.<ref>{{Cite journal|url=https://emedicine.medscape.com/article/297664-overview#a3|title=Chronic Obstructive Pulmonary Disease (COPD)|last=Mosenifar|first=Zab|date=April 2019|website=emedicine.medscape|access-date=25 July 2019}}</ref>

====Bullous====
[[File:Bullus emphasemaCT.png|thumb|CT scan of [[bullous emphysema]]]]
When the [[Focal lung pneumatosis|subpleural bullae]] are significant, the emphysema is called '''bullous emphysema'''. Bullae can become extensive and combine to form giant bullae. These can be large enough to take up a third of a hemithorax, compress the lung parenchyma, and cause displacement. The emphysema is now termed '''giant bullous emphysema''', more commonly called '''vanishing lung syndrome''' due to the compressed parenchyma.<ref name='Sharma'>{{cite journal |last1=Sharma |first1=N. |last2=Justaniah |first2=A. M. |title=Vanishing lung syndrome (giant bullous emphysema):CT findings in 7 patients and a literature review |journal=J Thoracic Imaging |date=August 2009 |volume=24 |issue=3 |pages=227–230 |pmid=19704328 |doi=10.1097/RTI.0b013e31819b9f2a |s2cid=882767 }}</ref> A [[Focal lung pneumatosis|bleb or bulla]] may sometimes rupture and cause a [[pneumothorax]].{{sfn|Kumar|2018|pp=498-501}}
[[File:Emphysema H and E.jpg|thumb|Stained lung tissue from end-stage emphysema.]]

===Paracicatricial===
Paracicatricial emphysema, also known as irregular emphysema, is seen next to areas of [[fibrosis]] (scarring) as large spaces. The scarring is most often a result of [[silicosis]], [[granuloma]]tous  infection, [[tuberculosis]], or [[pulmonary infarction]]. It can be difficult to differentiate from the [[honeycombing]] of [[pulmonary fibrosis]].<ref name='radiopedia2'>{{cite web |last1=Weerakkody |first1=Yuranga |title=Paracicatricial emphysema {{!}} Radiology Reference Article {{!}} Radiopaedia.org |url=https://radiopaedia.org/articles/paracicatricial-emphysema?lang=gb |website=Radiopaedia |access-date=28 July 2021}}</ref>

===HIV associated===
Classic lung diseases are a complication of [[HIV/AIDS]] with emphysema being a source of disease. HIV is cited as a risk factor for the development of emphysema, and COPD regardless of smoking status.<ref name='Kumar-2021'>{{cite journal |last1=Kumar |first1=A |last2=Mahajan |first2=A |last3=Salazar |first3=EA |last4=Pruitt |first4=K |last5=Guzman |first5=CA |last6=Clauss |first6=MA |last7=Almodovar |first7=S |last8=Dhillon |first8=NK |title=Impact of human immunodeficiency virus on pulmonary vascular disease |journal=Global Cardiology Science & Practice |date=30 June 2021 |volume=2021 |issue=2 |pages=e202112 |doi=10.21542/gcsp.2021.12 |pmid=34285903|pmc=8272407 }}</ref> Around 20 percent of those with HIV have increased emphysematous changes. This has suggested that an underlying mechanism related to HIV is a contributory factor in the development of emphysema. HIV associated emphysema occurs over a much shorter time than that associated with smoking; an earlier presentation is also seen in emphysema caused by [[alpha-1 antitrypsin deficiency]]. Both of these conditions predominantly show damage in the lower lungs which suggests a similarity between the two mechanisms.<ref name="Stephenson">{{cite journal |vauthors=Stephenson SE, Wilson CL, Crothers K, Attia EF, Wongtrakool C, Petrache I, Schnapp LM |title=Impact of HIV infection on α1-antitrypsin in the lung |journal=Am J Physiol Lung Cell Mol Physiol |volume=314 |issue=4 |pages=L583–L592 |date=April 2018 |pmid=29351445 |pmc=5966776 |doi=10.1152/ajplung.00214.2017 |url=}}</ref>

===Alpha-1 related===
Emphysema may develop in some people with [[alpha-1 antitrypsin deficiency]], the only [[Chronic obstructive pulmonary disease#Subtypes|genotype of chronic obstructive pulmonary disease]]. This usually occurs a lot earlier, as does HIV associated emphysema than other types.<ref name='medline2020'>{{cite web |title=Alpha-1 antitrypsin deficiency: MedlinePlus Genetics |url=https://medlineplus.gov/genetics/condition/alpha-1-antitrypsin-deficiency/ |website=medlineplus.gov |access-date=26 August 2021}}</ref>

===Ritalin lung===
The intravenous use of [[methylphenidate]], commonly marketed as ''Ritalin'' and widely used as a [[stimulant drug]] in the treatment of [[attention deficit hyperactivity disorder]], can lead to emphysematous changes known as '''Ritalin lung'''. The mechanism underlying this link is not clearly understood. Ritalin tablets contain [[talc]] as a filler, and these need to be crushed and dissolved for injecting. It has been suggested that the talc exposure causes [[granuloma]]tosis leading to alveolar destruction. However, other intravenous drugs also contain talc and there is no associated emphysematous change. [[High-resolution computed tomography|High resolution CT scanning]] shows the emphysema to be panlobular.<ref>{{Cite web|url=https://radiopaedia.org/articles/ritalin-lung?lang=gb|title=Ritalin lung|last=Sharma|first=R.|website=radiopaedia.org|access-date=9 July 2019}}</ref>

===CPFE===
[[Combined pulmonary fibrosis and emphysema]] (CPFE) is a rare syndrome that shows upper-lobe emphysema, together with lower-lobe interstitial fibrosis. This is diagnosed by [[CT scan]].<ref name='Wand'>{{Cite journal|last1=Wand|first1=O|last2=Kramer|first2=MR|date=January 2018|journal=Harefuah|volume=157|issue=1|pages=28–33|pmid=29374870|title=The Syndrome of Combined Pulmonary Fibrosis and Emphysema - CPFE}}</ref> This syndrome presents a marked susceptibility for the development of [[pulmonary hypertension]].<ref>{{Cite journal|last=Seeger|first=W|date=December 2013|title=Pulmonary hypertension in chronic lung diseases|journal=J Am Coll Cardiol|volume=62|issue=25 Suppl|pages=109–116|pmid=24355635|doi=10.1016/j.jacc.2013.10.036|doi-access=free}}</ref>

===Congenital lobar===
Congenital lobar emphysema (CLE), also known as congenital lobar overinflation and infantile lobar emphysema,<ref>{{cite web |title=UpToDate: Congenital lobar emphysema |url=http://www.uptodate.com/contents/congenital-lobar-emphysema |access-date=10 July 2016}}</ref> is a [[Pediatrics|neonatal condition]] associated with enlarged air spaces in the lungs of [[Infant|newborn infants]]. It is diagnosed around the time of birth or in the first 6 months of life, occurring more often in boys than girls. CLE affects the upper [[lung lobes]] more than the lower lobes, and the left lung more often than the right lung.<ref name="Guidry-2012"/> CLE is defined as the hyperinflation of one or more lobes of the lung due to the partial obstruction of the bronchus. This causes symptoms of pressure on the nearby organs. It is associated with several cardiac abnormalities such as [[patent ductus arteriosus]], [[atrial septal defect]], [[ventricular septal defect]], and [[tetralogy of Fallot]].<ref name='Demir 2019'>{{Cite journal|last=Demir|first=Omer|date=May 2019|title=Congenital lobar emphysema: diagnosis and treatment options|journal= International Journal of Chronic Obstructive Pulmonary Disease|volume=14|pages=921–928|pmid=31118601|pmc=6507121|doi=10.2147/COPD.S170581}}</ref> Although CLE may be caused by the abnormal development of [[bronchus|bronchi]], or compression of airways by nearby tissues, no cause is identified in half of cases.<ref name='Guidry-2012'>{{cite journal|last1=Guidry|first1=Christopher|last2=McGahren|first2=Eugene D.|title=Pediatric Chest I|journal=Surgical Clinics of North America|date=June 2012|volume=92|issue=3|pages=615–643|doi=10.1016/j.suc.2012.03.013|pmid=22595712}}<!--|access-date=28 September 2015--></ref> CT scan of the lungs is useful in assessing the anatomy of the lung lobes and status of the neighbouring lobes on whether they are hypoplastic or not. Contrast-enhanced CT is useful in assessing vascular abnormalities and mediastinal masses.<ref name='Demir 2019' />

===Focal===
[[File:Pneumot rax bullae.JPG|thumb|A large bulla and a smaller bleb illustrated]]
Focal emphysema, is a localized region of emphysema in the lung that is larger than alveoli, and often associated with [[coalworker's pneumoconiosis]].<ref name='Weinberger1'>{{cite book |last1=Weinberger |first1=S |last2=Cockrill |first2=B |last3=Mandel |first3=J |title=Principles of pulmonary medicine |date=2019 |isbn=9780323523714 |page=147 |edition=Seventh}}</ref> This is also known as ''localized pulmonary emphysema''.<ref name="Weerakkody1">{{cite web |last1=Weerakkody |first1=Yuranga |title=Localised pulmonary emphysema {{!}} Radiology Reference Article {{!}} Radiopaedia.org |url=https://radiopaedia.org/articles/localised-pulmonary-emphysema?lang=gb |website=Radiopaedia |access-date=2 August 2021}}</ref> [[Focal lung pneumatosis|Blebs and bullae]] may also be included as focal emphysema. These can be differentiated from the other type of enclosed air space known as a [[lung cyst]] by their size and wall thickness. A bleb or bulla  has a wall thickness of less than 1&nbsp;mm, and are smaller.<ref name='Gaillard'>{{cite web |last1=Gaillard |first1=Frank |title=Pulmonary bullae {{!}} Radiology Reference Article {{!}} Radiopaedia.org |url=https://radiopaedia.org/articles/pulmonary-bullae?lang=gb |website=Radiopaedia |access-date=16 June 2019}}</ref>

====Occupational====
A number of occupations<!--Replacing 'a number of... [which]?' with relevant examples would tread the interested reader better, instead of using weasel words.--> are associated with the development of emphysema due to the inhalation of varied gases and particles. In the US [[Uranium mining in the United States|uranium mining]] that releases [[radon gas]] and particles has been shown to be a cause of emphysema deaths; the figures in the study included some miners who also smoked. Uranium mining and milling was found to create environmental pollution.<ref name='NIOSH'>{{cite web |title=Worker Health Study Summaries - Uranium Miners {{!}} NIOSH {{!}} CDC |url=https://www.cdc.gov/niosh/pgms/worknotify/uranium.html |website=www.cdc.gov |access-date=29 July 2021 |date=15 June 2020}}</ref>

The inhalation of [[Coal mine|coal mine dust]] that can result in [[coalworker's pneumoconiosis]] is an independent risk factor for the development of emphysema. Focal emphysema is associated with the [[Coalworker's pneumoconiosis#Appearance|coal macule]], and this extends into progressive centrilobular emphysema. Less commonly a variant of panlobular emphysema develops.<ref name='NIOSH3'>{{cite web |title=Pathology Basis of Occupational Lung Disease, Pneumoconiosis {{!}} NIOSH {{!}} CDC |url=https://www.cdc.gov/niosh/learning/b-reader/pathology/pneumoconiosis/1.html |website=www.cdc.gov |access-date=31 July 2021 |date=5 August 2020}}</ref>

[[Silicosis]] results from the inhalation of [[silica]] particles, and the formation of large silica nodules is associated with paracicatricial emphysema, with or without bullae.<ref name='NIOSH4'>{{cite web |title=Pathology Basis of Occupational Lung Disease, Silicosis {{!}} NIOSH {{!}} CDC |url=https://www.cdc.gov/niosh/learning/b-reader/pathology/silicosis/1.html |website=www.cdc.gov |access-date=31 July 2021 |date=5 August 2020}}</ref>

====Ozone-induced emphysema====
[[Ozone]] is another [[pollutant]] that can affect the respiratory system. Long-term exposure to ozone can result in emphysema.<ref name='Mumby'>{{cite journal |vauthors=Mumby S, Chung KF, Adcock IM |title=Transcriptional Effects of Ozone and Impact on Airway Inflammation |journal=Front Immunol |volume=10 |issue= |pages=1610 |date=2019 |pmid=31354743 |pmc=6635463 |doi=10.3389/fimmu.2019.01610 |url=|doi-access=free }}</ref>

==Osteoporosis==
[[Osteoporosis]] is a major [[comorbidity]] of emphysema. Both conditions are associated with a low [[body mass index]].<ref name='Martinez2'>{{cite journal |last1=Martinez |first1=CH |last2=Han |first2=MK |title=Contribution of the environment and comorbidities to chronic obstructive pulmonary disease phenotypes. |journal=The Medical Clinics of North America |date=July 2012 |volume=96 |issue=4 |pages=713–27 |doi=10.1016/j.mcna.2012.02.007 |pmid=22793940|pmc=4629222 }}</ref> There is an association between treating emphysema, and [[osteoporosis]]; the use of [[systemic administration|systemic]] [[corticosteroids]] for treating [[Acute exacerbation of chronic obstructive pulmonary disease|exacerbations]] is a significant risk factor for osteoporosis, and their repeated use is not recommended.<ref name='Gold'/>

==Other terms==
{{Further|Pneumatosis}}
'''Compensatory emphysema''', is overinflation of part of a lung in response to either removal by surgery of another part of the lung or decreased size of another part of the lung.<ref>{{cite book |last1=Han |first1=Xinwei |last2=Wang |first2=Chen |title=Airway Stenting in Interventional Radiology |date=2018 |publisher=Springer |isbn=9789811316197 |page=27 |url=https://www.google.com/books/edition/Airway_Stenting_in_Interventional_Radiol/oQ92DwAAQBAJ?gbpv=1&pg=PA27 }}</ref>

[[Pulmonary interstitial emphysema]] (PIE) is a collection of [[air]] outside of the normal air space of the [[pulmonary alveolus|alveoli]], found as [[Pneumatosis|pneumatoses]] inside the [[connective tissue]] of the peribronchovascular sheaths, interlobular septa, and [[pulmonary pleurae|visceral pleura]].

==Lung volume reduction==
'''Lung volume reduction''' may be offered to those with advanced emphysema. When other treatments fail, and the emphysema is located in the upper lobes, a surgical option may be possible.<ref name='Marchetti1'/> A number of minimally invasive [[bronchoscopic]] procedures are increasingly used to reduce lung volume.<ref name='Duffy'>{{cite journal |vauthors=Duffy S, Marchetti N, Criner GJ |title=Surgical Therapies for Chronic Obstructive Pulmonary Disease |journal=Clin Chest Med |volume=41 |issue=3 |pages=559–566 |date=September 2020 |pmid=32800206 |doi=10.1016/j.ccm.2020.06.011 |s2cid=221145423 |url=}}</ref>

===Surgical===
Where there is severe emphysema with significant hyperinflation that has proved unresponsive to other therapies, [[lung volume reduction surgery]] (LVRS) may be an option.{{sfn|Gold Report 2021|p=96|loc=Chapter 4: Management of stable COPD}}<ref name='Lancet2019'>{{cite journal |display-authors=et al.|last1=van Geffen |first1=WH |last2=Slebos |first2=DJ |last3=Herth |first3=FJ |title=Surgical and endoscopic interventions that reduce lung volume for emphysema: a systemic review and meta-analysis. |journal=The Lancet. Respiratory Medicine |date=April 2019 |volume=7 |issue=4 |pages=313–324 |doi=10.1016/S2213-2600(18)30431-4 |pmid=30744937|s2cid=73428098 |url=https://pure.rug.nl/ws/files/81829213/1_s2.0_S2213260018304314.pdf }}</ref> LVRS involves the removal of tissue from the lobe most damaged by emphysema, which allows the other lobes to expand and give improved function. The procedure appears to be particularly effective if the emphysema primarily involves the upper lobes; however, the procedure increases the risk of adverse events and early death in people who have diffuse emphysema.<ref>{{cite journal | vauthors = van Agteren JE, Carson KV, Tiong LU, Smith BJ | title = Lung volume reduction surgery for diffuse emphysema | journal = The Cochrane Database of Systematic Reviews | volume = 2016 | pages = CD001001 | date = October 2016 | issue = 10 | pmid = 27739074 | doi = 10.1002/14651858.CD001001.pub3 | pmc = 6461146 }}</ref><ref name='Marchetti1' />

===Bronchoscopic===
{{Further|Bronchoscopic lung volume reduction}}
Minimally invasive bronchoscopic procedures may be carried out to reduce lung volume. These include the use of valves, coils, or thermal ablation.{{sfn|Gold Report 2021|pp=60–65|loc=Chapter 3: Evidence supporting prevention and maintenance therapy}}<ref name='NICE2'>{{cite web |title=1 Recommendations {{!}} Endobronchial valve insertion to reduce lung volume in emphysema {{!}} Guidance {{!}} NICE |url=https://www.nice.org.uk/guidance/ipg600/chapter/1-Recommendations |website=www.nice.org.uk |access-date=7 July 2021}}</ref> [[Endobronchial valve]]s are one-way valves that may be used in those with severe hyperinflation resulting from advanced emphysema; a suitable target lobe and no [[collateral ventilation]] are required for this procedure. The placement of one or more valves in the lobe induces a partial [[atelectasis|collapse]] of the lobe that ensures a reduction in residual volume that improves lung function, the capacity for exercise, and quality of life.<ref name='Klooster'>{{cite journal |vauthors=Klooster K, Slebos DJ |title=Endobronchial Valves for the Treatment of Advanced Emphysema |journal=Chest |volume=159 |issue=5 |pages=1833–1842 |date=May 2021 |pmid=33345947 |pmc=8129734 |doi=10.1016/j.chest.2020.12.007 |url=}}</ref>

The placement of [[nitinol]] coils instead of valves is recommended where there is collateral ventilation that would prevent the use of valves.<ref name='Welling'>{{cite journal |vauthors=Welling JB, Slebos DJ |title=Lung volume reduction with endobronchial coils for patients with emphysema |journal=J Thorac Dis |volume=10 |issue=Suppl 23 |pages=S2797–S2805 |date=August 2018 |pmid=30210833 |pmc=6129816 |doi=10.21037/jtd.2017.12.95 |url=}}</ref> Nitinol  is a [[Nitinol biocompatibility|biocompatible]] [[shape-memory alloy]].

Both of these techniques are associated with adverse effects, including persistent air leaks and cardiovascular complications. Bronchoscopic thermal vapor ablation has an improved profile. Heated water vapor is used to target affected lobe regions, which leads to permanent fibrosis and volume reduction. The procedure is able to target individual lobe segments, can be carried out regardless of collateral ventilation, and can be repeated with the natural advance of emphysema.<ref name='Valipour'>{{cite journal |last1=Valipour |first1=Arschang |title=Bronchoscopic Thermal Vapour Ablation: Hot Stuff to Treat Emphysema Patients! |url=https://www.archbronconeumol.org/en-bronchoscopic-thermal-vapour-ablation-hot-articulo-S1579212916302725 |journal=Archivos de Bronconeumología (English Edition) |access-date=3 July 2021 |pages=1–2 |doi=10.1016/j.arbr.2016.11.009 |date=1 January 2017|volume=53 |issue=1 |pmid=27916315 }}</ref>

==Other surgeries==
[[Lung transplantation]] – the replacement of either a single lung or both (bilateral) – may be considered in [[End stage pulmonary disease|end-stage disease]]. A bilateral transplant is the preferred choice as complications can arise in a remaining single native lung; complications can include hyperinflation, pneumonia, and the development of lung cancer.<ref name='ATM'>{{cite journal |vauthors=Inci I |title=Lung transplantation for emphysema |journal=Ann Transl Med |volume=8 |issue=21 |pages=1473 |date=November 2020 |pmid=33313218 |pmc=7723607 |doi=10.21037/atm-20-805 |url=}}</ref> Careful selection as recommended by the ''National Emphysema Treatment Trial'' (NETT) for transplant surgeries is needed as in some cases there will be an increased risk of mortality.<ref name="Marchetti1">{{cite journal |vauthors=Marchetti N, Criner GJ |title=Surgical Approaches to Treating Emphysema: Lung Volume Reduction Surgery, Bullectomy, and Lung Transplantation |journal=Semin Respir Crit Care Med |volume=36 |issue=4 |pages=592–608 |date=August 2015 |pmid=26238644 |doi=10.1055/s-0035-1556064 |url=}}</ref> Several factors including age, and poor exercise tolerance, using the [[BODE index]] need to be taken into account.<ref name='ATM' />  A transplant is only considered where there are no serious comorbidites.<ref name='Duffy' /> A [[CT scan]] or a [[ventilation/perfusion scan]] may be useful in surgery considerations to evaluate cases for surgical interventions, and also to evaluate post-surgery responses.<ref name='seminars'>{{cite journal |title=Lung Scintigraphy in COPD |url=https://reader.elsevier.com/reader/sd/pii/S000129981830076X?token=C202D11DAF6C8584FC21325C49134ACFB1C427FD59B38FE213BCF0B2C07CEFA848E90BE846ABCEE944604AB88B05A4EB&originRegion=eu-west-1&originCreation=20210704123426 |journal=Seminars in Nuclear Medicine |access-date=4 July 2021 |pages=16–21 |doi=10.1053/j.semnuclmed.2018.10.010 |date=1 January 2019|last1 = Mortensen|first1 = Jann|last2 = Berg|first2 = Ronan M.G.|volume = 49|issue = 1|pmid = 30545511|s2cid = 56486118}}</ref> A [[bullectomy]] may be carried out when a giant bulla occupies more than a third of a hemithorax.<ref name='Duffy' />

==History==
[[File:Giambattista morgagni.gif|thumb|upright=0.6|[[Giovanni Battista Morgagni]], who recorded one of the earliest descriptions of emphysema in 1769]]
The terms ''emphysema'' and ''chronic bronchitis'' were formally defined in 1959 at the [[Novartis|CIBA]] guest symposium, and in 1962 at the [[American Thoracic Society]] Committee meeting on Diagnostic Standards.<ref name='Petty' /> The word ''emphysema'' is derived from [[Ancient Greek]] ἐμφύσημα 'inflation, swelling'<ref>{{Cite web |title=Greek Word Study Tool - ἐμφύσημα |url=http://www.perseus.tufts.edu/hopper/morph?l=%E1%BC%90%CE%BC%CF%86%CF%8D%CF%83%CE%B7%CE%BC%CE%B1&la=greek#lexicon |access-date=2021-08-25 |website=www.perseus.tufts.edu}}</ref> (referring to a lung inflated by air-filled spaces), itself from {{lang|el|ἐμφυσάω}} ''emphysao'' 'to blow in, to inflate',<ref>{{Cite web|title=Greek Word Study Tool|url=http://www.perseus.tufts.edu/hopper/morph?l=%E1%BC%90%CE%BC%CF%86%CF%85%CF%83%CE%AC%CF%89&la=greek#lexicon |access-date=2021-08-25 |website=www.perseus.tufts.edu}}</ref> composed of ἐν ''en'', meaning "''in''", and φυσᾶ ''physa'',<ref>{{Cite web |title=Greek Word Study Tool |url=http://www.perseus.tufts.edu/hopper/morph?l=%E1%BC%90%CE%BC%CF%86%CF%8D%CF%83%CE%B7%CE%BC%CE%B1&la=greek#lexicon |access-date=2021-08-25 |website=www.perseus.tufts.edu}}</ref> meaning "''wind, blast''{{-"}}.{{sfn||Klein|1971|p=245}}<ref>{{cite web|title=Emphysema|url=http://dictionary.reference.com/browse/emphysema|work=Dictionary.com|access-date=21 November 2013|url-status=live|archive-url=https://web.archive.org/web/20131124023213/http://dictionary.reference.com/browse/emphysema|archive-date=24 November 2013}}</ref>

[[René Laennec]], the physician who invented the [[stethoscope]], used the term ''emphysema'' in his book ''A Treatise on the Diseases of the Chest and of Mediate Auscultation'' (1837) to describe lungs that did not collapse when he opened the chest during an autopsy.<ref name="Petty">{{cite journal | vauthors = Petty TL | title = The history of COPD | journal = International Journal of Chronic Obstructive Pulmonary Disease | volume = 1 | issue = 1 | pages = 3–14 | year = 2006 | pmid = 18046898 | pmc = 2706597 | doi = 10.2147/copd.2006.1.1.3 }}</ref> He noted that they did not collapse as usual because they were full of air and the airways were filled with mucus.<ref name='Petty' /> Early descriptions of probable emphysema include: in 1679 by T. Bonet of a condition of "voluminous lungs" and in 1769 by [[Giovanni Morgagni]] of lungs which were "turgid particularly from air".<ref name='Petty' />{{sfn|Wright|Churg|2008|pp=693–705}} In 1721 the first drawings of emphysema were made by Ruysh.{{sfn|Wright|Churg|2008|pp=693–705}} These were followed the illustrations of [[Matthew Baillie]] in 1789 and descriptions of the destructive nature of the condition.<!--<ref name=History2006/> -->

==References==
{{Reflist}}

==Bibliography==
{{refbegin|30em}}
* {{Cite book |last=Klein |first=Ernest |url=https://books.google.com/books?id=CWUYAAAAIAAJ |title=A Comprehensive Etymological Dictionary of the English Language |date=1971 |publisher=Elsevier Publishing Company |isbn=978-0-444-40930-0 }}
* {{Cite book |title=Robbins Basic Pathology |last=Kumar |first=Vinay |publisher=Elsevier |year=2018 |isbn=9780323353175}}
* {{cite book |first1=Joanne L. |last1=Wright |first2=Andrew |last2=Churg |name-list-style=vanc |chapter=Pathologic Features of Chronic Obstructive Pulmonary Disease: Diagnostic Criteria and Differential Diagnosis |chapter-url=http://www.mhprofessional.com/downloads/products/0071457399/0071457399_chap40.pdf |editor1-first=Alfred |editor1-last=Fishman |editor2-first=Jack |editor2-last=Elias |editor3-first=Jay |editor3-last=Fishman |editor4-first=Michael |editor4-last=Grippi |editor5-first=Robert |editor5-last=Senior |editor6-first=Allan |editor6-last=Pack |year=2008 |title=Fishman's Pulmonary Diseases and Disorders |edition=4th |publisher=McGraw-Hill |isbn=978-0-07-164109-8 |access-date=2021-08-14 |archive-date=2016-03-03 |archive-url=https://web.archive.org/web/20160303202744/http://www.mhprofessional.com/downloads/products/0071457399/0071457399_chap40.pdf |url-status=dead }}
{{refend}}

==External links==
{{Medical resources
| ICD10           = {{ICD10|J43}}, {{ICD10|P25.0}}
}}

[[Category:Chronic lower respiratory diseases]]
[[Category:Health effects of tobacco]]
[[Category:Occupational diseases]]