If you are experiencing a medical emergency please dial 911 immediately
It is possible that the main title of the report Orthostatic Hypotension is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Orthostatic hypotension (OH) describes an extreme drop in blood pressure that may occur when a person stands up suddenly causing the blood to pool in the blood vessels of the legs. Because of this pooling, the amount of blood carried back to the heart by the veins is decreased. Subsequently, less blood is pumped out from the heart, resulting in a sudden drop in blood pressure. By definition, the drop in blood pressure must be greater than 20 mm of mercury during contraction of the heart muscles (systole) and more than 10 mm of mercury during expansion of the heart muscles (diastole). Among children and teenagers, short-lived episodes of OH are normal and not uncommon. Episodes among the elderly are always to be taken seriously. Furthermore, feeling light-headed when first standing up is not cause for alarm, but losing consciousness, even if only briefly, should be reported to a medical professional immediately.
Normally, specialized cells in the body (baroreceptors) quickly respond to changes in blood pressure. These baroreceptors then activate the autonomic nervous system to increase, via reflex action, and increase levels of catecholamines (e.g. epinephrine, norepinephrine) in the body. Increased catecholamine levels rapidly restore the blood pressure. A defect in this spontaneous response (reflex) prevents the heart rate and blood pressure from rising adequately and orthostatic hypotension results. Fainting and falling are the usual consequences.
NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Vanderbilt's Autonomic Dysfunction Center
Vanderbilt University Medical Center
1211 Medical Center Drive
Nashville, TN 37232-2195
National Dysautonomia Research Foundation
PO Box 301
Red Wing, MN 55066-0102
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
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Last Updated: 9/15/2011
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