orthostatic intolerance


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orthostatic intolerance

A condition (OMIM:604715) characterised by lightheadedness, fatigue, altered mentation, syncope and tachycardia upon assuming an upright position, and markedly elevated serum norepinephrine. 

Molecular pathology
Defects in SLC6A2, which encodes a member of the sodium:neurotransmitter symporter that regulates norepinephrine homeostasis, are a cause of orthostatic intolerance.

or·tho·stat·ic in·tol·er·ance

(ōr'thō-stat'ik in-tol'ĕr-ăns)
Decreased venous return in the upright position typically experienced by astronauts after returning to an environment subject to gravity.

orthostatic intolerance

Loss of consciousness, near fainting, or light-headedness occurring when a person stands up from a seated or resting position. It is caused by insufficient blood flow to the brain, typically brought on by inability to raise blood pressure during changes in posture.
References in periodicals archive ?
Thus far, there are no valid tests to detect orthostatic intolerance leading to syncope among patients with MD.
This can also result in problems from low blood pressure and heart rate control called orthostatic intolerance and POTS.
They were healthy children without syncope, chest tightness, headache, or other symptoms of orthostatic intolerance, as demonstrated by a normal medical history, physical examination, and laboratory findings.
[11] described two types of clinical image of NCS based on a classification of the aforementioned symptoms: (1) haematuria, proteinuria, and left flank pain were labeled as a renal presentation, and (2) the remaining symptoms (varicocele, abdominal pain, dyspareunia, dysmenorrhea, fatigue, and orthostatic intolerance) were grouped as a urologicpresentation.
* Postexertional malaise * * Unrefreshing sleep * Plus at least one of the two following manifestations (chronic, severe): * Cognitive impairment * * Orthostatic intolerance Source: Institute of Medicine.
Alteration in arterial tone is believed to be caused by the local remodeling within vascular wall, and it may play a significant role in weightlessness-induced orthostatic intolerance [35].
Orthostatic intolerance. Symptoms have been shown to worsen with an upright posture according to objective measures such as orthostatic vital signs and head-up tilt testing, and symptoms improve with rest and leg elevation.
In addition, patients should have cognitive impairment and/or experience orthostatic intolerance. The symptoms should persist for at least 6 months at a moderate, substantial, or severe intensity at least half of the time.
Additionally, patients should have cognitive impairment and/or experience orthostatic intolerance. The symptoms should persist for at least 6 months at a moderate, substantial, or severe intensity at least half of the time.
An Italian study on a volleyball player who had "acute psychosis" after high consumption of Red Bull, published in "The Journal of the Clinical Autonomic Research Society", concluded that "Considering the widespread of use of Red Bull among young who are often unaware of the drink's content, this case report suggests Red Bull be considered a possible cause of orthostatic intolerance." This means the abnormal and sudden increase in heartbeat rate.
Finally, Twisk suggests that cognitive deficits in ME/CFS can be explained by neurological abnormalities and changes in brain structure and function [2], including orthostatic intolerance and a reduction in gray matter volume, among others.