orthostatic intolerance


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orthostatic intolerance

an abnormal response to standing upright that results from decreased blood pressure and inadequate blood flow to the brain, characterized by a variety of symptoms, including lightheadedness, palpitations, tremulousness, visual disturbances, and syncope. It occurs in both acute and chronic forms and is frequently seen as a transient condition in space travelers returning from microgravity. The cause is unknown but may be related to abnormalities in the autonomic regulation of cardiovascular function.

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 ?
Postexertional malaise, unrefreshing sleep, and cognitive impairment and/or orthostatic intolerance are the other defining characteristics of SEID.
Postural orthostatic tachycardia syndrome (POTS) is one of the most prevalent presentations of orthostatic intolerance (1, 2) and is defined as an increase in heart rate of 30 beats per minute (bpm) or more within 10 minutes of standing in adults, or 40 bpm or more in children (3), typically with associated symptoms of orthostatic intolerance, and in the absence of orthostatic hypotension, prolonged bed rest, medications that impair autonomic regulation, and any debilitating disorder causing tachycardia (i.
In addition, patients should have cognitive impairment and/or experience orthostatic intolerance.
Additionally, patients should have cognitive impairment and/or experience orthostatic intolerance.
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.
He is the principal investigator on National Institutes of Health-funded studies on the pathophysiology of orthostatic intolerance, autoimmune autonomic ganglionopathy, and hypoglycemia and the autonomic nervous system.
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.
It was three years and 60 different tests before he was finally diagnosed with orthostatic intolerance, a malfunction of the nervous system which causes a delay in adequate blood supply to the " brain.
He suffered from orthostatic intolerance, a malfunction of the nervous system which causes a delay in adequate blood supply to the brain.
Orthostatic intolerance and tachycardia associated with norepinephrine-transporter deficiency.
3 bpm, with 18 of 31 (58%) patients meeting criteria for orthostatic intolerance (an increase of more than 30 bpm).