Editing Diffuse axonal injury (section)

==Mechanism==
DAI is the result of [[Physical trauma|traumatic]] [[Shearing (physics)|shearing]] forces that occur when the head is rapidly accelerated or decelerated, as may occur in car accidents, falls, and assaults.<ref>{{cite journal | vauthors = Gennarelli TA | title = Mechanisms of brain injury | journal = The Journal of Emergency Medicine | volume = 11 | pages = 5–11 | date = 1993 | issue = Suppl 1 | pmid = 8445204 }}</ref> Vehicle accidents are the most frequent cause of DAI; it can also occur as the result of [[child abuse]]<ref name="Hardman02"/> such as in [[shaken baby syndrome]].<ref name="SmithGreenwald">Smith D. and Greenwald B. 2003.[https://web.archive.org/web/20050909140825/http://www.emedicine.com/pmr/topic213.htm  Management and staging of traumatic brain injury]. Emedicine.com. Retrieved through web archive on 17 January 2008.</ref>

Immediate disconnection of [[axon]]s may be observed in severe brain injury, but the major damage of DAI is delayed secondary axon disconnections, slowly developed over an extended time course.<ref name="Axonal change in minor head injury"/> Tracts of axons, which appear white due to [[myelination]], are referred to as [[white matter]]. Lesions in both grey and white matter are found in postmortem brains in CT and MRI exams.<ref name="Wasserman"/>

Besides mechanical breakage of the axonal [[cytoskeleton]], DAI pathology also includes secondary physiological changes, such as interrupted axonal transport, progressive swellings known as [[axonal varicosities]], and degeneration.<ref name="pmid22285252">{{cite journal | vauthors = Johnson VE, Stewart W, Smith DH | title = Axonal pathology in traumatic brain injury | journal = Experimental Neurology | volume = 246 | pages = 35–43 | date = August 2013 | pmid = 22285252 | pmc = 3979341 | doi = 10.1016/j.expneurol.2012.01.013 | series = Special Issue: Axonal degeneration }}</ref> Recent studies have linked these changes to twisting and misalignment of broken axon [[microtubule]]s, as well as [[tau protein]] and [[amyloid precursor protein]] (APP) deposition.<ref name="pmid22285252"/><ref>{{cite journal | vauthors = Tang-Schomer MD, Patel AR, Baas PW, Smith DH | title = Mechanical breaking of microtubules in axons during dynamic stretch injury underlies delayed elasticity, microtubule disassembly, and axon degeneration | journal = FASEB Journal | volume = 24 | issue = 5 | pages = 1401–10 | date = May 2010 | pmid = 20019243 | pmc = 2879950 | doi = 10.1096/fj.09-142844 | doi-access = free }}</ref>