Editing Orthostatic intolerance (section)

===Acute orthostatic intolerance===

Patients who have acute OI usually manifest the disorder by a temporary [[loss of consciousness]] and [[List of human positions|posture]], with rapid recovery (simple [[fainting|faints]], or [[Syncope (medicine)|syncope]]), as well as remaining conscious during their loss of posture.  This is different from a syncope caused by [[Cardiovascular disease|cardiac problems]] because the triggers for the fainting spell (standing, heat, [[emotion]]) and identifiable [[prodromal]] symptoms (nausea, blurred vision, headache) are known.  As  Dr. Julian M. Stewart, an expert in OI from [[New York Medical College]] states, "Many syncopal patients have no intercurrent illness; between faints, they are well."<ref name=overview/>

'''Symptoms:'''<ref name="nymc">{{cite web | title = Orthostatic Intolerance | author = Julian M. Stewart | publisher = New York Medical College | url = http://www.nymc.edu/fhp/centers/syncope/orthostatic_intolerance.htm | access-date = 2007-08-20 | archive-url = https://web.archive.org/web/20070806053841/http://nymc.edu/fhp/centers/syncope/orthostatic_intolerance.htm | archive-date = 2007-08-06 | url-status = dead }}</ref>
* [[Visual impairment|Altered vision]] ([[blurred vision]], "white outs"/[[Greyout|gray outs]], [[Syncope (medicine)|black outs]], [[diplopia|double vision]])
* [[Anxiety]]
* [[Exercise intolerance]]
* [[Fatigue (medical)|Fatigue]]
* [[Headache]]
* [[Heart palpitations]], as the [[Tachycardia|heart races]] to compensate for the [[Hypotension|falling blood pressure]]
* [[Hyperpnea]] or sensation of [[Shortness of breath|difficulty breathing]] or [[Dysphagia|swallowing]] (see also [[hyperventilation syndrome]])
* [[Lightheadedness]]
* [[Sweating]]
* [[Tremulousness]]
* [[Weakness]]

A classic manifestation of acute OI is a soldier who faints after standing rigidly at attention for an extended period of time.