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Alternative NamesLow blood pressure; Blood pressure - low; Postprandial hypotension; Orthostatic hypotension; Neurally mediated hypotension; NMH
Definition Return to top
Low blood pressure, or hypotension, occurs when blood pressure during and after each heartbeat is much lower than usual. This means the heart, brain, and other parts of the body do not get enough blood.
See also: Blood pressure
Causes Return to top
Blood pressure that is borderline low for one person may be normal for another. The most important factor is how the blood pressure changes from the normal condition.
Most normal blood pressures fall in the range of 90/60 millimeters of mercury (mm Hg) to 130/80 mm Hg. But a significant drop, even as little as 20 mm Hg, can cause problems for some people.
There are three main types of hypotension:
Orthostatic hypotension is brought on by a sudden change in body position, usually when shifting from lying down to standing. This type of hypotension usually lasts only a few seconds or minutes. If this type of hypotension occurs after eating, it is called postprandial orthostatic hypotension. This form most commonly affects older adults, those with high blood pressure, and persons with Parkinson's disease.
NMH most often affects young adults and children. It occurs when a person has been standing for a long time. Children usually outgrow this type of hypotension.
Low blood pressure is commonly caused by drugs such as:
Other causes of low blood pressure include:
Symptoms Return to top
Symptoms may include:
Exams and Tests Return to top
The health care provider will examine you and try to determine what is causing the low blood pressure. Your vital signs (temperature, pulse, rate of breathing, blood pressure) will be checked frequently. You may need to stay in the hospital for a while.
The doctor will ask questions, including:
The following tests may be done:
Treatment Return to top
Hypotension in a healthy person that does not cause any problems usually doesn't require treatment.
If you have signs or symptoms of low blood pressure, you may need treatment. Treatment depends on the cause of your low blood pressure. Severe hypotension caused by shock is a medical emergency. You may be given blood through a needle (IV), medicines to increase blood pressure and improve heart strength, and other medicines, such as antibiotics. For more details, see the article on shock.
If you have orthostatic hypotension caused by medicines, your doctor may change the dose or switch you to a different drug. DO NOT stop taking any medicine before talking to your doctor. Other treatments for orthostatic hypotension include increasing fluids to treat dehydration or wearing elastic hose to boost blood pressure in the lower part of the body.
Those with NMH should avoid triggers, such as standing for a long period of time. Other treatments involve drinking plenty of fluids and increasing the amount of salt in your diet. (Ask your doctor about specific recommendations.) In severe cases, medicines such as fludrocortisone may be prescribed.
Outlook (Prognosis) Return to top
Low blood pressure can usually be treated with success.
Possible Complications Return to top
Falls are particularly dangerous for older adults. Fall-related injuries, such as a broken hip, can dramatically impact a person's quality of life.
Severe hypotension starves your body of oxygen, which can damage the heart, brain, and other organs. This type of hypotension can be life threatening if not immediately treated.
When to Contact a Medical Professional Return to top
When you have symptoms from a drop in blood pressure, you should immediately sit or lie down and raise your feet above heart level.
If low blood pressure causes a person to pass out (become unconscious), seek immediate medical treatment or call the local emergency number (such as 911). If the person is not breathing or has no pulse, begin CPR.
Call your doctor immediately if you have any of the following symptoms:
Also call your doctor if you have:
Prevention Return to top
If you have low blood pressure, your doctor may recommend certain steps to prevent or reduce your symptoms. This may include:
References Return to topCalkins H, Zipes DP. Hypotension and syncope. In: Libby P, Bonow RO, Mann DL, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 37. Update Date: 2/22/2009 Updated by: Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.