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Orthostatic hypotension, also known as postural hypotension, [2] is a medical condition wherein a person's blood pressure drops when they are standing up (orthostasis) or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension. [ 3 ]
Orthostatic intolerance occurs in humans because standing upright is a fundamental stressor, so requires rapid and effective circulatory and neurologic compensations to maintain blood pressure, cerebral blood flow, and consciousness. When a human stands, about 750 ml of thoracic blood are abruptly translocated downward.
Postural orthostatic tachycardia syndrome (POTS) is a condition characterized by an abnormally large increase in heart rate upon sitting up or standing. [1] POTS is a disorder of the autonomic nervous system that can lead to a variety of symptoms, [10] including lightheadedness, brain fog, blurred vision, weakness, fatigue, headaches, heart palpitations, exercise intolerance, nausea ...
Orthostatic syncope refers to syncope resulting from a postural decrease in blood pressure, termed orthostatic hypotension. [1] Orthostatic hypotension occurs when there is a persistent reduction in blood pressure of at least 20mmHg systolic or 10mmHg diastolic within 3 minutes of standing or being upright to 60 degrees on the head-up tilt ...
Syncope, commonly known as fainting or passing out, is a loss of consciousness and muscle strength characterized by a fast onset, short duration, and spontaneous recovery. [1] It is caused by a decrease in blood flow to the brain, typically from low blood pressure. [1] There are sometimes symptoms before the loss of consciousness such as ...
Dysautonomia, autonomic failure, or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has many causes, not all of which may be classified as neuropathic. [5]
Pure autonomic failure (PAF) is an uncommon, sporadic neurodegenerative condition marked by a steadily declining autonomic regulation. [3] Bradbury and Eggleston originally described pure autonomic failure in 1925. [4] Patients usually present with orthostatic hypotension or syncope in midlife or later.
Reflex syncope. Reflex syncope is a brief loss of consciousness due to a neurologically induced drop in blood pressure and/or a decrease in heart rate. [5][6][7][8][9][10][2] Before an affected person passes out, there may be sweating, a decreased ability to see, or ringing in the ears. [1] Occasionally, the person may twitch while unconscious. [1]