Orthostatic intolerance

Orthostatic intolerance (OI) is the development of symptoms when standing upright that are relieved when reclining. There are many types of orthostatic intolerance. OI can be a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up. Some animal species with orthostatic hypotension have evolved to cope with orthostatic disturbances. A substantial overlap is seen between syndromes of orthostatic intolerance on the one hand, and either chronic fatigue syndrome or fibromyalgia on the other. It affects more women than men (female-to-male ratio is at least 4:1), usually under the age of 35. 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. People who have OI lack the basic mechanisms to compensate for this deficit. Changes in heart rate, blood pressure, and cerebral blood flow that produce OI may be caused by abnormalities in the interactions between blood volume control, the cardiovascular system, the nervous system, and circulation control system. Orthostatic intolerance is divided, roughly based on patient history, in two variants: acute and chronic. Patients who have acute OI usually manifest the disorder by a temporary loss of consciousness and posture, with rapid recovery (simple faints, or syncope), as well as remaining conscious during their loss of posture. This is different from a syncope caused by 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.

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Related publications (11)

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Climate change is predicted to increase atmospheric vapor pressure deficit, exacerbating soil drought, and thus enhancing tree evaporative demand and mortality. Yet, few studies have addressed the longer-term drought acclimation strategy of trees, particul ...

Oxford2024

Implanted System for Orthostatic Hypotension in Multiple-System Atrophy

Grégoire Courtine, Jocelyne Bloch, Jordan Squair, Léonie Asboth, Robin Jonathan Demesmaeker, Nicolas Hankov, Sergio Daniel Hernandez, Grégory Didier Dumont, Suje Amir, Maxime Berney

Orthostatic hypotension is a cardinal feature of multiple-system atrophy. The upright posture provokes syncopal episodes that prevent patients from standing and walking for more than brief periods. We implanted a system to restore regulation of blood press ...

MASSACHUSETTS MEDICAL SOC2022

Effect of Lower Limb vs. Abdominal Compression on Mobility in Orthostatic Hypotension: A Single-Blinded, Randomized, Controlled, Cross-Over Pilot Study in Parkinson's Disease

Kamiar Aminian, Arash Atrsaei

Background: Orthostatic hypotension (OH) in Parkinson's disease (PD) is frequent and associated with impairments in quality of life and reduced activities of daily living. Abdominal binders (AB) and compression stockings (CS) have been shown to be effectiv ...

IOS PRESS2022

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Postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is a condition characterized by an abnormally large increase in heart rate upon standing. POTS is a disorder of the autonomic nervous system that can lead the individual to experience a variety of symptoms. Symptoms may include lightheadedness, brain fog, blurred vision, weakness, fatigue, headaches, heart palpitations, exercise intolerance, nausea, diminished concentration, tremulousness (shaking), syncope (fainting), coldness or pain in the extremities, chest pain and shortness of breath.

Long COVID

Long COVID or long-haul COVID is a series of health problems persisting or developing after an initial COVID-19 infection. Symptoms can last weeks, months or years and are often debilitating. The World Health Organization defines long COVID to start three months after infection, but other definitions put the start of long COVID at four weeks. Long COVID is characterised by a large number of symptoms. Symptoms sometimes disappear and reappear. Commonly reported symptoms of long COVID are fatigue, memory problems, shortness of breath, and sleep disorder.

Dysautonomia

Dysautonomia 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. A number of conditions can feature dysautonomia, such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, Ehlers-Danlos syndromes, autoimmune autonomic ganglionopathy and autonomic neuropathy, HIV/AIDS, autonomic failure, and postural orthostatic tachycardia syndrome.