Editing Human brain (section)

===Stroke===
{{Main|Stroke}}
[[File:Parachemableedwithedema.png|thumb|upright|[[CT scan]] of a [[cerebral hemorrhage]], showing an [[intraparenchymal bleed]] (bottom arrow) with surrounding [[edema]] (top arrow)]]

<!--Definitions and symptoms-->A [[stroke]] is a [[ischemia|decrease in blood supply]] to an area of the brain causing [[cell death]] and [[Brain damage#Causes|brain injury]]. This can lead to a wide range of [[Stroke#Signs and symptoms|symptoms]], including the "[[FAST (stroke)|FAST]]" symptoms of facial droop, arm weakness, and speech difficulties (including [[dysarthria|with speaking]] and [[dysphasia|finding words or forming sentences]]).<ref>{{cite journal |last1=Harbison |first1=J. |last2=Massey |first2=A. |last3=Barnett |first3=L. |last4=Hodge |first4=D. |last5=Ford |first5=G.A. | title=Rapid ambulance protocol for acute stroke | journal=Lancet | volume=353 | issue=9168 | page=1935 | date=June 1999 | pmid=10371574 | doi=10.1016/S0140-6736(99)00966-6 |s2cid=36692451 }}</ref> Symptoms relate to the function of the affected area of the brain and can point to the likely site and cause of the stroke. Difficulties with movement, speech, or sight usually relate to the cerebrum, whereas [[ataxia|imbalance]], [[diplopia|double vision]], [[vertigo]] and symptoms affecting more than one side of the body usually relate to the brainstem or cerebellum.{{sfn|Davidson's|2010|p=1183}}

Most strokes result from loss of blood supply, typically because of an [[embolus]], rupture of a [[atheroma|fatty plaque]] causing [[thrombus]], or [[arteriosclerotic|narrowing of small arteries]]. Strokes can also result from [[Stroke#Hemorrhagic|bleeding within the brain]].{{sfn|Davidson's|2010|pp=1180-1}} [[Transient ischemic attack|Transient ischaemic attack]]s (TIAs) are strokes in which symptoms resolve within 24 hours.{{sfn|Davidson's|2010|pp=1180-1}} Investigation into the stroke will involve a [[medical examination]] (including a [[neurological examination]]) and the taking of a [[medical history]], focusing on the duration of the symptoms and risk factors (including [[Hypertension|high blood pressure]], [[atrial fibrillation]], and [[tobacco smoking|smoking]]).{{sfn|Davidson's|2010|pp=1181, 1183-1185}} Further investigation is needed in younger patients.{{sfn|Davidson's|2010|pp=1183-1185}} An [[ECG]] and [[biotelemetry]] may be conducted to identify [[atrial fibrillation]]; an [[ultrasound]] can investigate [[carotid stenosis|narrowing]] of the [[Common carotid artery|carotid arteries]]; an [[echocardiogram]] can be used to look for clots within the heart, [[Valvular heart disease|diseases of the heart valves]] or the presence of a [[patent foramen ovale]].{{sfn|Davidson's|2010|pp=1183-1185}} [[Blood test]]s are routinely done as part of the [[Medical diagnosis#Other diagnostic procedure methods|workup]] including [[Diabetes mellitus#Diagnosis|diabetes tests]] and a [[lipid profile]].{{sfn|Davidson's|2010|pp=1183-1185}}

Some treatments for stroke are time-critical. These include [[thrombolysis|clot dissolution]] or [[embolectomy|surgical removal of a clot]] for [[Brain ischemia|ischaemic strokes]], and [[decompression (surgery)|decompression]] for [[Intracranial hemorrhage|haemorrhagic strokes]].{{sfn|Davidson's|2010|pp=1185-1189}}<ref>{{cite journal |last1=Goyal |first1=M. |display-authors=etal |title=Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials |journal=The Lancet |date=April 2016 |volume=387 |issue=10029 |pages=1723–1731 |doi=10.1016/S0140-6736(16)00163-X |pmid=26898852 |s2cid=34799180 }}</ref> As stroke is time critical,<ref>{{cite journal |last1=Saver |first1=J. L. |title=Time is brain—quantified |journal=Stroke |date=December 8, 2005 |volume=37 |issue=1 |pages=263–266 |doi=10.1161/01.STR.0000196957.55928.ab|pmid=16339467 |doi-access=free }}</ref> hospitals and even pre-hospital care of stroke involves expedited investigations – usually a [[CT scan]] to investigate for a haemorrhagic stroke and a [[CT angiogram|CT]] or [[MR angiogram]] to evaluate arteries that supply the brain.{{sfn|Davidson's|2010|pp=1183-1185}} [[MRI scan]]s, not as widely available, may be able to demonstrate the affected area of the brain more accurately, particularly with ischaemic stroke.{{sfn|Davidson's|2010|pp=1183-1185}}

Having experienced a stroke, a person may be admitted to a [[stroke unit]], and treatments may be directed as [[secondary prevention|preventing]] future strokes, including ongoing [[anticoagulation]] (such as [[aspirin]] or [[clopidogrel]]), [[Antihypertensive drug|antihypertensives]], and [[lipid-lowering agent|lipid-lowering drugs]].{{sfn|Davidson's|2010|pp=1185-1189}} A [[multidisciplinary team]] including [[speech pathologist]]s, [[physiotherapists]], [[occupational therapist]]s, and [[psychologist]]s plays a large role in supporting a person affected by a stroke and their [[physical medicine and rehabilitation|rehabilitation]].<ref>{{cite journal |last1=Winstein |first1=C.J. |display-authors=etal |title=Guidelines for adult stroke rehabilitation and recovery |journal=Stroke |date=June 2016 |volume=47 |issue=6 |pages=e98–e169 |doi=10.1161/STR.0000000000000098|pmid=27145936 |s2cid=4967333 |doi-access=free }}</ref>{{sfn|Davidson's|2010|pp=1183-1185}} A history of stroke increases the risk of developing dementia by around 70%, and recent stroke increases the risk by around 120%.<ref>{{Cite journal|last1=Kuźma|first1=Elżbieta|last2=Lourida|first2=Ilianna|last3=Moore|first3=Sarah F.|last4=Levine|first4=Deborah A.|last5=Ukoumunne|first5=Obioha C.|last6=Llewellyn|first6=David J.|date=November 2018 |title=Stroke and dementia risk: A systematic review and meta-analysis|journal=Alzheimer's & Dementia |volume=14 |issue=11 |pages=1416–1426 |doi=10.1016/j.jalz.2018.06.3061 |pmid=30177276|pmc=6231970|issn=1552-5260}}</ref>