Editing Infarction

{{Short description|Tissue death due to inadequate blood supply}}
{{Distinguish|Infection|Infraction}}
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| caption         = [[Micrograph]] of a pulmonary infarct (right of image) beside relatively normal lung (left of image). [[H&E stain]].
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'''Infarction''' is tissue death ([[necrosis]]) due to [[Ischemia|inadequate blood supply]] to the affected area. It may be caused by [[Thrombosis|artery blockages]], rupture, mechanical compression, or [[vasoconstriction]].<ref>{{cite web |url=http://www.medterms.com/script/main/art.asp?articlekey=3970 |work=MedicineNet |publisher=[[WebMD]] |title=Definition of Infarction |date=April 27, 2011 |access-date=August 19, 2011 |archive-date=January 23, 2014 |archive-url=https://web.archive.org/web/20140123012700/http://www.medterms.com/script/main/art.asp?articlekey=3970 |url-status=dead }}</ref> The resulting [[lesion]] is referred to as an infarct<ref>{{cite web |url=http://www.thefreedictionary.com/infarct |publisher=[[TheFreeDictionary.com]] |title=infarct}} Citing:
* The American Heritage Dictionary of the English Language, Fourth Edition. Updated in 2009.
* The American Heritage Science Dictionary 2005 by Houghton Mifflin Company.
</ref><ref>[http://www.collinsdictionary.com/dictionary/english/infract infract]. CollinsDictionary.com. Collins English Dictionary&nbsp;– Complete & Unabridged 11th Edition. Retrieved November 22, 2012.</ref>
(from the Latin ''infarctus'', "stuffed into").<ref>{{Cite web|url=http://www.etymonline.com/index.php?term=infarct&allowed_in_frame=0|title=Infarct &#124; Origin and meaning of infarct by Online Etymology Dictionary}}</ref>

==Causes==
{{Unreferenced section|date=August 2011}}
Infarction occurs as a result of prolonged [[ischemia]], which is the insufficient supply of oxygen and nutrition to an area of tissue due to a disruption in blood supply.<ref>{{Cite journal |last=Heusch |first=Gerd |date=2024-01-12 |title=Myocardial ischemia/reperfusion: Translational pathophysiology of ischemic heart disease |url=https://www.sciencedirect.com/science/article/pii/S2666634023004051 |journal=Med |volume=5 |issue=1 |pages=10–31 |doi=10.1016/j.medj.2023.12.007 |issn=2666-6340}}</ref> The blood vessel supplying the affected area of tissue may be blocked due to an obstruction in the vessel (e.g.,&nbsp;an [[arterial embolus]], [[thrombus]], or [[atherosclerotic plaque]]), compressed by something outside of the vessel causing it to narrow (e.g.,&nbsp;[[tumor]], [[volvulus]], or [[hernia]]), ruptured by trauma causing a loss of blood pressure downstream of the rupture, or vasoconstricted, which is the narrowing of the blood vessel by contraction of the muscle wall rather than an external force (e.g.,&nbsp;cocaine vasoconstriction leading to [[myocardial infarction]]).<ref>{{Cite web |title=Infarction - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/infarction#:~:text=Infarction%20is%20tissue%20death%20or,,%20lung,%20etc.). |access-date=2023-04-01 |website=www.sciencedirect.com}}</ref>
[[File:Atherosclerosis timeline - endothelial dysfunction.svg|left|thumb|200x200px|Infarction could be caused by damaged cholesterol plaque]]
[[Hypertension]] and [[atherosclerosis]] are risk factors for both [[atherosclerotic plaque]]s and [[thromboembolism]]. In atherosclerotic formations, a plaque develops under a fibrous cap. When the fibrous cap is degraded by metalloproteinases released from macrophages or by intravascular shear force from blood flow, subendothelial thrombogenic material ([[extracellular matrix]]) is exposed to circulating platelets and thrombus formation occurs on the vessel wall [[Vascular occlusion|occluding]] blood flow. Occasionally, the plaque may rupture and form an [[Embolism|embolus]] which travels with the blood-flow downstream to where the vessel narrows and eventually clogs the vessel lumen.

==Classification==
[[File:InfarctPandLbasilarsegmentsPE.PNG|thumb|Infarction of the lung due to a pulmonary embolism]]

===By histopathology===
[[File:Thrombosis.png|200px|thumbnail|left|A blood clot could be a broken thrombosis that got clotted to the blood vessel wall.]]
Infarctions are divided into two types according to the amount of [[blood]] present:
# [[White infarction]]s ([[anemic infarct]]s) affect solid organs such as the [[spleen]], [[heart]] and [[kidneys]] wherein the solidity of the [[tissue (biology)|tissue]] substantially limits the amount of nutrients ([[blood]]/[[oxygen]]/[[glucose]]/[[fuel]]) that can flow into the [[area]] of [[ischaemic]] [[necrosis]]. Similar [[Vascular occlusion|occlusion]] to [[blood flow]] and consequent [[necrosis]] can occur as a result of severe [[vasoconstriction]] as illustrated in severe [[Raynaud's phenomenon]] that can lead to irreversible [[gangrene]].
# [[Red infarction]]s ([[hemorrhagic infarct]]s) generally affect the [[lung]]s or other loose organs ([[testis]], [[ovary]], [[small intestines]]). The [[Vascular occlusion|occlusion]] consists more of [[red blood cell]]s and [[fibrin]] strands. Characteristics of red infarcts include:
#* occlusion of a [[vein]]
#* loose tissues that allow [[blood]] to collect in the [[infarcted]] zone
#* tissues with a dual [[circulatory system]] (lung, small intestines)
#* tissues previously congested from sluggish venous outflow
#* [[Reperfusion injury|reperfusion]] ([[injury]])<ref>{{cite journal |pages=654–7 |doi=10.1038/365654a0 |title=Prevention of lung reperfusion injury in rabbits by a monoclonal antibody against interleukin-8 |year=1993 |last1=Sekido |first1=Nobuaki |last2=Mukaida |first2=Naofumi |last3=Harada |first3=Akihisa |last4=Nakanishi |first4=Isao |last5=Watanabe |first5=Yoh |last6=Matsushima |first6=Kouji |journal=Nature |volume=365 |issue=6447 |pmid=8413628|bibcode=1993Natur.365..654S |s2cid=4282441 }}</ref> of previously [[ischemic]] tissue that is associated with [[Reperfusion injury|reperfusion]]-related [[diseases]],<ref>
{{cite journal |pages=1907–1916 |doi=10.1517/13543784.8.11.1907 |title=LEX 032: a novel recombinant human protein for the treatment of ischaemic reperfusion injury |year=1999 |last1=Sands |first1=Howard |last2=Tuma |first2=Ronald F |journal=Expert Opinion on Investigational Drugs |volume=8 |issue=11 |pmid=11139833}}
</ref> such as [[myocardial infarction]], [[stroke]] ([[cerebral infarction]]), shock-[[resuscitation]], replantation [[surgery]], [[frostbite]], [[burn]]s, and [[organ transplant]]ation.
[[File:Hemorrhagic infarction of testis.jpg|thumbnail|Micrograph of testis showing hemorrhagic infarction. [[H&E]] stain.]]

===By localization===
* [[File:Haem infarction, small bowel.jpg|thumb|Haemorrhagic infarction ileum; strangulation in a hernial sack.]][[File:Haemorragic infarct, apex l lower lobe left lung.jpg|thumb|Hemorrhagic infarct, apex lower lobe, left lung]]'''Heart''': [[Myocardial infarction]] (''MI''), commonly known as a ''heart attack'', is an infarction of the heart, causing some heart cells to die. This is most commonly due to occlusion (blockage) of a [[coronary artery]] following the rupture of a [[Vulnerable plaque|vulnerable atherosclerotic plaque]], which is an unstable collection of [[lipids]] (fatty acids) and [[white blood cell]]s (especially [[macrophage]]s) in the wall of an [[artery]]. The resulting [[ischemia]] (restriction in blood supply) and [[Hypoxia (medical)|oxygen shortage]], if left untreated for a sufficient period of time, can cause damage or kill heart muscle tissue (''[[myocardium]]'').
[[File:Histopathology of thalamus infarction at approximately 24 hours, high magnification, annotated.jpg|thumb|240px|Histopathology at high magnification of a normal brain neuron, and a brain infarction at approximately 24 hours on [[H&E stain]]: The neurons become hypereosinophilic and there is an infiltrate of [[neutrophil]]s. There is slight edema and loss of normal architecture in the surrounding [[neuropil]].]]
* '''Brain''': [[Cerebral infarction]] is the [[ischemia|ischemic]] kind of [[stroke]] due to a disturbance in the blood vessels supplying blood to the brain. It can be atherothrombotic or embolic.<ref>{{cite book |last1=Ropper |first1=Allan H. |last2=Adams |first2=Raymond Delacy |last3=Brown |first3=Robert F. |last4=Victor |first4=Maurice |title=Adams and Victor's principles of neurology |year=2005 |publisher=McGraw-Hill Medical Pub. Division |location=New York  |isbn=0-07-141620-X |pages=686–704}}</ref> Stroke caused by cerebral infarction should be distinguished from two other kinds of stroke: [[cerebral hemorrhage]] and [[subarachnoid hemorrhage]]. Cerebral infarctions vary in their severity with one third of the cases resulting in death. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.<ref>{{Cite book|url=https://www.worldcat.org/oclc/879416939|title=Robbins and Cotran pathologic basis of disease|date=2015|others=Vinay Kumar, Abul K. Abbas, Jon C. Aster, James A. Perkins|isbn=978-1-4557-2613-4|edition=Ninth|location=Philadelphia, PA|oclc=879416939}}</ref>
* '''Lung''': Pulmonary infarction or [[lung Infarction|lung infarction]]
* '''Spleen''': [[Splenic infarction]] occurs when the [[splenic artery]] or one of its branches are occluded, for example by a [[blood clot]]. Although it can occur [[asymptomatic]]ally, the typical symptom is severe [[abdominal pain|pain]] in the [[left upper quadrant (abdomen)|left upper quadrant of the abdomen]], sometimes radiating to the left shoulder. Fever and chills develop in some cases.<ref name="pmid9486895">{{cite journal |pmid=9486895 |year=1998 |last1=Nores |first1=M |last2=Phillips |first2=EH |last3=Morgenstern |first3=L |last4=Hiatt |first4=JR |title=The clinical spectrum of splenic infarction |volume=64 |issue=2 |pages=182–8 |journal=The American Surgeon}}</ref> It has to be differentiated from other causes of [[acute abdomen]].
* '''Limb''': [[Limb infarction]] is an infarction of an [[arm]] or [[leg]]. Causes include [[arterial embolism]]s and ''skeletal muscle infarction'' as a rare complication of long standing, poorly controlled [[diabetes mellitus]].<ref name=Grigoriadis>{{cite journal |pmid=10782838 |year=2000 |last1=Grigoriadis |first1=E |last2=Fam |first2=AG |last3=Starok |first3=M |last4=Ang |first4=LC |title=Skeletal muscle infarction in diabetes mellitus |volume=27 |issue=4 |pages=1063–8 |journal=The Journal of Rheumatology}}</ref> A major presentation is painful thigh or leg swelling.<ref name=Grigoriadis/>
* '''Bone''': Infarction of [[bone]] results in [[avascular necrosis]]. Without blood, the bone tissue dies and the bone collapses.<ref name=DiGiovanni>{{cite journal |pmid=17426292 |year=2007 |last1=Digiovanni |first1=CW |last2=Patel |first2=A |last3=Calfee |first3=R |last4=Nickisch |first4=F |title=Osteonecrosis in the foot |volume=15 |issue=4 |pages=208–17 |journal=The Journal of the American Academy of Orthopaedic Surgeons |doi=10.5435/00124635-200704000-00004|s2cid=31296534 }}</ref> If avascular necrosis involves the bones of a [[joint]], it often leads to destruction of the joint articular surfaces (see [[osteochondritis dissecans]]).
* '''Testicle''': an infarction of a [[testicle]] is commonly caused by [[testicular torsion]] and may require [[Orchiectomy|removal of the affected testicle]](s) if not undone by surgery quickly enough.<ref>{{Cite web|title=Testicular torsion - Symptoms and causes|url=https://www.mayoclinic.org/diseases-conditions/testicular-torsion/symptoms-causes/syc-20378270|access-date=2021-08-10|website=Mayo Clinic|language=en}}</ref>

[[File:Segmental testicular infarction 112914968.jpg|thumb|Ultrasound of segmental testicular infarction. Infarct area shown as hypoechoic and avascular upper segment of R testis.]]

* '''Eye''': an infarction can occur to the [[central retinal artery]] which supplies the retina causing sudden visual loss.
*'''Bowel''': [[Bowel infarction]] is generally caused by [[mesenteric ischemia]] due to blockages in the arteries or veins that supply the bowel.

==Associated diseases==
{{unreferenced section|date=May 2013}}
Diseases commonly associated with infarctions include:

* [[Peripheral artery occlusive disease]] (the most severe form of which is [[gangrene]])
* [[Antiphospholipid syndrome]]
* [[Sepsis]]
* [[Giant-cell arteritis]] (GCA)
* [[Hernia]]
* [[Volvulus]]
* [[Sickle-cell disease]]

== First aid ==
Each type of infarction requires its own care.

Infarction in the heart requires [[Management of acute coronary syndrome#Patient-dependent initial measures|first aid for myocardial infarction (due to acute coronary syndrome)]].

Infarction in the brain requires [[FAST (stroke)|first aid for stroke (using a protocol named F.A.S.T.).]]

==References==
{{Reflist}}

== External links ==
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{{Hemodynamics}}
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[[Category:Gross pathology]]
[[Category:Causes of death]]