Synonyms

• Postural Hypotension

Disorder Subdivisions

• None

General Discussion

Orthostatic hypotension (OH) describes an extreme drop in blood pressure that may occur when a person stands up suddenly and the blood pools 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.

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, 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.

Some clinical neurologists prefer to focus on three primary syndromes of the failure or breakdown of the autonomic nervous system. These are:

Acute or subacute idiopathic pandysautonomia (ASIP) refers to the breakdown of the autonomic nervous system (control of breathing, blood circulation, pain, taste, etc.) from unknown causes.

Pure autonomic failure (PAF) is sometimes defined as the presence of orthostatic hypotension (without an identifiable cause such as medically prescribed drugs) without evidence of any other neurological problem(s). This term, according to an international consensus committee, replaces Bradbury-Egglestone syndrome, idiopathic orthostatic hypotension, and progressive autonomic failure.

Resources

National Institute of Neurological Disorders and Stroke (NINDS)
31 Center Drive
8A07
Bethesda, MD 20892-2540
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
Email: braininfo@ninds.nih.gov
Internet: http://www.ninds.nih.gov/

Autonomic Dysfunction Center
Vanderbilt University Medical Center
AA3228 MCN
Nashville, TN 37232-2195
USA
Tel: 6153436499
Fax: 6153438649
Email: david.robertson@vanderbilt.edu
Internet: http://www.mc.vanderbilt.edu/gcrc/adc

National Dysautonomia Research Foundation
PO Box 301
Red Wing, MN 55066-0102
Tel: (651)267-0525
Fax: (651)267-0524
Email: ndrf@ndrf.org
Internet: http://www.ndrf.org

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html

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.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

Last Updated:  3/14/2008
Copyright  1990, 1992, 1995, 1996, 1997, 2003National Organization for Rare Disorders, Inc.