orthostatic hypotension

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Orthostatic Hypotension



Orthostatic hypotension is an abnormal decrease in blood pressure when a person stands up. This may lead to fainting.


When a person stands upright, a certain amount of blood normally pools in the veins of the ankles and legs. This pooling means that there is slightly less blood for the heart to pump and causes a drop in blood pressure. Usually, the body responds to this drop so quickly, a person is unaware of the change. The brain tells the blood vessels to constrict so they have less capacity to carry blood, and at the same time tells the heart to beat faster and harder. These responses last for a very brief time. If the body's response to a change in vertical position is slow or absent, the result is orthostatic hypotension. It is not a true disease, but the inability to regulate blood pressure quickly.

Causes and symptoms

Orthostatic hypotension has many possible causes. The most common cause is medications used to treat other conditions. Diuretics reduce the amount of fluid in the body which reduces the volume of blood. Medicines used to expand the blood vessels increase the vessel's ability to carry blood and so lower blood pressure.
If there is a severe loss of body fluid from vomiting, diarrhea, untreated diabetes, or even excessive sweating, blood volume will be reduced enough to lower blood pressure. Severe bleeding can also result in orthostatic hypotension.
Any disease or spinal cord injury that damages the nerves which control blood vessel diameter can cause orthostatic hypotension.
Symptoms of orthostatic hypotension include faintness, dizziness, confusion, or blurry vision, when standing up quickly. An excessive loss of blood pressure can cause a person to pass out.


When a person experiences any of the symptoms above, a physician can confirm orthostatic hypotension if the person's blood pressure falls significantly on standing up and returns to normal when lying down. The physician will then look for the cause of the condition.


When the cause of orthostatic hypotension is related to medication, it is often possible to treat it by reducing dosage or changing the prescription. If it is caused by low blood volume, an increase in fluid intake and retention will solve the problem.
Medications designed to keep blood pressure from falling can be used when they will not interfere with other medical problems.
When orthostatic hypotension cannot be treated, the symptoms can be significantly reduced by remembering to stand up slowly or by wearing elastic stockings.


The prognosis for people who have orthostatic hypotension depends on the underlying cause of the problem.


There is no way to prevent orthostatic hypotension, since it is usually the result of another medical condition.



National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.
National Organization for Rare Disorders. P.O. Box 8923, New Fairfield, CT 06812-8923. (800) 999-6673. http://www.rarediseases.org.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


diminished tension; lowered blood pressure. A consistently low blood pressure (systolic pressure less than 100 mm of mercury) usually is no cause for concern. In fact, low blood pressure often is associated with long life. However, extremely low blood pressure may be a sign of a serious condition such as shock, massive hemorrhage, hypovolemia, or severe dehydration from nausea and vomiting. In shock there is a disproportion between the blood volume and the capacity of the circulatory system, resulting in greatly reduced blood pressure. Hypotension may also be associated with addison's disease or inadequate thyroid function, but in both cases the primary disease produces so many other symptoms that the hypotension is not a major focus for concern.
orthostatic hypotension (postural hypotension) a fall in blood pressure (usually defined as a 20 to 30 point change in pulse or blood pressure), associated with dizziness, syncope, and blurred vision, occurring when a person goes from lying down or sitting to standing; it can be acquired or idiopathic, transient or chronic, and may occur alone or secondary to a disorder of the central nervous system such as the shy-drager syndrome.
supine hypotension vena caval syndrome.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

or·tho·stat·ic hy·po·ten·sion

a form of low blood pressure that occurs in a standing posture.
Farlex Partner Medical Dictionary © Farlex 2012

orthostatic hypotension

Clinical medicine An abrupt ↓ in BP which occurs either when one stands up or when one remains in for a prolonged period of time in an erect position Clinical Dizziness, faintness, syncope, dim or tunnel vision–↓ cerebral blood flow; Sx typically improve with recumbency; OH occurs in normal healthy people who rise quickly from a chair, especially after a meal Etiology Autonomic failure, which may be 1º, or 2º to sympatholytic drugs, or irritation of the sympathetic nervous system, as in DM and late syphilis, where sympathetic vasoconstrictor fibers attempt to compensate for effects of gravity. See Autonomic failure.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

or·tho·stat·ic hy·po·ten·sion

(ōr-thō-statik hīpō-tenshŭn)
A form of low blood pressure that occurs in a standing patient.
Synonym(s): postural hypotension.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

or·tho·stat·ic hy·po·ten·sion

(ōr-thŏ-statik hīpō-tenshŭn)
A form of low blood pressure that occurs in a standing patient.
Synonym(s): postural hypotension.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
However, the uncertainties in low diagnosis rate, lack of clinical evidence and unfavorable safety profile of OH drugs, and adoption of non-pharmacological treatment options as first line therapy may hamper the growth of orthostatic hypotension drugs market over the forecast period.
Treatment of post-dialytic orthostatic hypotension with an inflatable abdominal band in hemodialysis patients.
Adjustments in antihypertensives can be made in cases of orthostatic hypotension. (17) Antiemetics (ondansetron, promethazine, metoclopramide), antihistamines (meclizine, dimenhydrinate, diphenhydramine), and benzodiazepines (lorazepam, diazepam) may be used during acute and brief vertiginous episodes to decrease symptom severity after central causes have been ruled out.
Patients with vasodepressor and mixed syncope and those with orthostatic hypotension most of all need reassurance regarding the benign nature of the condition.
In our meta-analysis, we analyzed five new clinical features (depression, orthostatic hypotension, motor fluctuation, wearing-off, and freezing) and updated data of five previous analyzed clinical features (family history, AAO, UPDRSIII, H-Y, and dementia).
Kira, "A case of relapsing multiple sclerosis presenting with only autonomic symptoms including orthostatic hypotension, hiccups and vomiting," Journal of Clinical Neurology, vol.
Orthostatic hypotension is defined as a decrease in systolic BP (SBP) of 20 mm Hg and/or in diastolic BP (DBP) of 10 mm Hg within 3 min of standing.
However, for frail individuals, especially bed-ridden patients who have other medical conditions, and those who experience dizziness when standing up due to a drop in the BP (orthostatic hypotension), a more liberal approach is recommended, with a systolic BP target of less than 140 mmHg as an ideal level.
In most of the previous studies, squatting position has been used to evaluate patients with Tetralogy of Fallot, individuals prone to vasovagal syncope, and heart transplant including diabetic cardiovascular autonomic neuropathy, and also been used as a therapeutic means to counteract the fall in BP in patients suffering from dizziness and orthostatic hypotension or presenting pre-syncope symptoms, such as soon after exercise.
A variety of factors can cause orthostatic hypotension. They include medical conditions, such as heart failure or thyroid disease, as well as temporary conditions, such as dehydration or prolonged bed rest.
This can lead to a natriuresis, the excessive urinary excretion of sodium causing symptomatic hyponatremia and orthostatic hypotension (Hamdi et al., 2009).
Previous research suggests that the reduction in blood flow to the brain that accompanies orthostatic hypotension can contribute to memory problems and declines in brain function in older individuals.