Editing Reflex syncope (section)

{{short description|Brief loss of consciousness due to a neurologically induced drop in blood pressure}}
{{cs1 config|name-list-style=vanc}}
{{Distinguish|Vagovagal reflex}}
{{Use dmy dates|date=August 2016}}
{{Infobox medical condition (new)
| name            = Reflex syncope
| synonyms        = Neurally mediated syncope, neurocardiogenic syncope<ref name=Ay2010/><ref name=Ad2017/>
| image           = Gray793.png
| caption         = [[Vagus nerve]]
| field           = [[Neurology]], [[cardiology]], [[emergency medicine]]
| symptoms        = [[Loss of consciousness]] before which there may be sweating, decreased ability to see, [[tinnitus|ringing in the ears]]<ref name=Ay2010/><ref name=Ad2017/>
| complications   = Injury<ref name=Ay2010/>
| onset           =
| duration        = Brief<ref name=Ay2010/>
| types           = Vasovagal, situational, carotid sinus syncope<ref name=Ay2010/>
| causes          =
| risks           =
| diagnosis       = Based on symptoms after ruling out other possible causes<ref name=Bri2011/>
| differential    = [[Heart arrhythmia|Arrhythmia]], [[orthostatic hypotension]], [[seizure]], [[hypoglycemia]]<ref name=Ay2010/>
| prevention      =
| treatment       = Avoiding triggers, drinking sufficient fluids, exercise, [[cardiac pacemaker]]<ref name=Ad2017/>
| medication      = [[Midodrine]], [[fludrocortisone]]<ref name=Shen2017/>
| prognosis       =
| frequency       = > 1 per 1,000 people per year<ref name=Ay2010/>
| deaths          =
}}
<!-- Definition and symptoms -->

'''Reflex syncope''' is a brief [[loss of consciousness]] due to a [[nervous system|neurologically]] induced drop in [[blood pressure]] and/or a  decrease  in  heart  rate.<ref>Morillo   CA,   Eckberg   DL,   Ellenbogen   KA,   Beightol   LA,   Hoag   JB,   Tahvanainen KU, Kuusela TA, Diedrich AM. Vagal and sympathetic mecha-nisms in patients with orthostatic vasovagal syncope. Circulation. 1997;96: 2509–2513. doi: 10.1161/01.cir.96.8.2509</ref><ref>Abboud    FM.    Neurocardiogenic    syncope.    N    Engl    J    Med.    1993: 1117–1120. doi: 10.1056/NEJM199304153281510</ref><ref>Chen-Scarabelli   C,   Scarabelli   TM.   Neurocardiogenic   syncope.   BMJ.2004;329:336–341. doi: 10.1136/bmj.329.7461.336Abboud FM. Neuro-cardiogenic syncope. N Engl J Med. 1993;328:1117–1120. doi: 10.1056/NEJM199304153281510</ref><ref>Grubb  BP.  Clinical  practice.  Neurocardiogenic  syncope.  N  Engl  J  Med.2005;352:1004–1010. doi: 10.1056/NEJMcp042601</ref><ref>Barón-Esquivias   G,   Cayuela   A,   Gómez   S,   Aguilera   A,   Campos   A,   Fernández M, Cabezón S, Morán JE, Valle JI, Martínez A, et al. [Quality of life in patients with vasovagal syncope. Clinical parameters influence]. Med Clin (Barc). 2003;121:245–249. doi: 10.1016/s0025-7753(03)75188-4</ref><ref>Zheng L, Sun W, Liu S, et al. The Diagnostic Value of Cardiac Deceleration Capacity in Vasovagal Syncope.   ''Circ. Arrhythm. electrophysiol..'' 2020;13(12):e008659. doi:10.1161/CIRCEP.120.008659, 10.1161/CIRCEP.120.008659</ref><ref name=Ad2017>{{cite journal|last1=Adkisson|first1=WO|last2=Benditt|first2=DG|title=Pathophysiology of reflex syncope: A review.|journal=Journal of Cardiovascular Electrophysiology|date=September 2017|volume=28|issue=9|pages=1088–1097|doi=10.1111/jce.13266|pmid=28776824|s2cid=39638908}}</ref> Before an affected person passes out, there may be sweating, a decreased ability to see, or [[tinnitus|ringing in the ears]].<ref name=Ay2010>{{cite journal|last1=Aydin|first1=MA|last2=Salukhe|first2=TV|last3=Wilke|first3=I|last4=Willems|first4=S|title=Management and therapy of vasovagal syncope: A review.|journal=World Journal of Cardiology|date=26 October 2010|volume=2|issue=10|pages=308–15|doi=10.4330/wjc.v2.i10.308|pmid=21160608|pmc=2998831 |doi-access=free }}</ref> Occasionally, the person may twitch while unconscious.<ref name=Ay2010/> Complications of reflex syncope include injury due to a fall.<ref name=Ay2010/>

<!-- Cause and diagnosis -->
Reflex syncope is divided into three types: vasovagal, situational, and carotid sinus.<ref name=Ad2017/> Vasovagal syncope is typically triggered by seeing [[blood]], pain, emotional stress, or prolonged standing.<ref name=NIH2017>{{cite web|title=Syncope Information Page|url=https://www.ninds.nih.gov/Disorders/All-Disorders/Syncope-Information-Page|website=National Institute of Neurological Disorders and Stroke|access-date=9 November 2017}}</ref> Situational syncope is often triggered by [[urination]], swallowing, or coughing.<ref name=Ad2017/> Carotid sinus syncope is due to pressure on the [[carotid sinus]] in the neck.<ref name=Ad2017/> The underlying mechanism involves the [[nervous system]] slowing the heart rate and dilating blood vessels, resulting in low blood pressure and thus not enough blood flow to the brain.<ref name=Ad2017/> Diagnosis is based on the symptoms after ruling out other possible causes.<ref name=Bri2011>{{cite book|last1=Brignole|first1=Michele|last2=Benditt|first2=David G.|title=Syncope: An Evidence-Based Approach|date=2011|publisher=Springer Science & Business Media|isbn=9780857292018|page=158|url=https://books.google.com/books?id=i-p7twz4qyIC&pg=PA158}}</ref>

<!-- Treatment and epidemiology -->
Recovery from a reflex syncope episode happens without specific treatment.<ref name=Ad2017/> Prevention of episodes involves avoiding a person's triggers.<ref name=Ad2017/> Drinking sufficient fluids, salt, and exercise may also be useful.<ref name=Ad2017/><ref name=Shen2017>{{cite journal|last1=Shen|first1=WK|last2=Sheldon|first2=RS|last3=Benditt|first3=DG|last4=Cohen|first4=MI|last5=Forman|first5=DE|last6=Goldberger|first6=ZD|last7=Grubb|first7=BP|last8=Hamdan|first8=MH|last9=Krahn|first9=AD|last10=Link|first10=MS|last11=Olshansky|first11=B|last12=Raj|first12=SR|last13=Sandhu|first13=RK|last14=Sorajja|first14=D|last15=Sun|first15=BC|last16=Yancy|first16=CW|title=2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.|journal=Circulation|date=1 August 2017|volume=136|issue=5|pages=e25–e59|doi=10.1161/CIR.0000000000000498|pmid=28280232|doi-access=free}}</ref> If this is insufficient for treating vasovagal syncope, medications such as [[midodrine]] or [[fludrocortisone]] may be tried.<ref name=Shen2017/> Occasionally, an [[artificial cardiac pacemaker]] may be used as treatment.<ref name=Ad2017/> Reflex syncope affects at least 1 in 1,000 people per year.<ref name=Ay2010/> It is the most common type of [[Syncope (medicine)|syncope]], making up more than 50% of all cases.<ref name=Ad2017/>