Low Blood Pressure
Low blood pressure occurs when blood pressure is much lower than normal. This means the heart, brain, and other parts of the body do not get enough blood. Normal blood pressure is usually between 90/60 mmHg and 130/80 mmHg.
The medical name for low blood pressure is hypotension.
Low blood pressure; Blood pressure - low; Postprandial hypotension; Orthostatic hypotension; Neurally mediated hypotension; NMH
Blood pressurevaries fromone personto another.A drop as little as 20 mmHg, can cause problems for some people. There are different types and causes of low blood pressure.
Orthostatic hypotension iscaused by a sudden change in body position. This occursmost often when youshift from lying down to standing. This type oflow blood pressureusually lasts only a few seconds or minutes. If this type oflow blood pressureoccurs after eating, it is called postprandial orthostatic hypotension. Thistype mostoften affects older adults, those with high blood pressure, and persons with Parkinson disease.
Neurally mediated hypotension (NMH)most often affects young adults and children. Itcan occur when a person has been standing for a long time. Children usually outgrow this type of hypotension.
Certainmedicines and substancescan lead to low blood pressure,including:
- Anti-anxiety medicines
- Certain antidepressants
- Heart medicines, including those used to treat high blood pressure and coronary heart disease
- Medicines used for surgery
Other causes of low blood pressure include:
- Nerve damage from diabetes
- Changes in heart rhythm (arrhythmias)
- Not drinking enough fluids (dehydration)
- Heart failure
Symptoms of low blood pressuremay include:
- Blurry vision
- Fainting (syncope)
- Nausea or vomiting
Exams and Tests
The health care provider will examine you to determinethe cause of yourlow 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:
- What is your normal blood pressure?
- What medications do you take?
- Have you been eating and drinking normally?
- Have you had any recent illness, accident, or injury?
- What other symptoms do you have?
- Did you faint or become less alert?
- Do you feel dizzy or light-headed when standing or sitting after lying down?
The following tests may be done:
- Basic metabolic panel
- Blood cultures to check for infection
- Complete blood count (CBC), including blood differential
- X-ray of the abdomen
- X-ray of the chest
Lower than normalblood pressurein a healthy person that does not cause anysymptomsoften does notneed treatment. Otherwise, treatment depends on the cause of your low blood pressure and your symptoms.
When you have symptoms from a drop in blood pressure, sit or lie down right away. Then raise your feet above heart level.
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
- Other medicines, such as antibiotics
Treatments for low blood pressure after standing up too quickly include:
- If medicines are the cause, your doctor may change the dosage or switch you to a different drug. Do notstop taking any medicines before talking to your doctor.
- Your doctor may suggest drinkingmore fluids to treat dehydration.
- Wearingcompression stockings can help keep blood from collecting in the legs. This keeps more blood in the upper body.
Personswith NMH should avoid triggers, such as standing for a long period of time. Other treatments include drinking fluids and increasing salt in your diet. Talk to your doctor before trying these measures. In severe cases, medicines may be prescribed.
Low blood pressure can usually be treated with success.
Falls due to low blood pressure in older adultscan lead to a broken hip or spinefracture. These injuries can reduce a person's health and ability to move around
Sudden severe drops in your blood pressure starves your body of oxygen. This can lead to damage of the heart, brain, and other organs. This type oflow blood pressurecan be life threatening if not treated right away.
When to Contact a Medical Professional
If low blood pressure causes a person to pass out (become unconscious), seek treatment right away.Or call the local emergency number such as 911. If the person is not breathing or has no pulse, begin CPR.
Call your doctorright awayif you have any of the following symptoms:
- Black or maroon stools
- Chest pain
- Dizziness, lightheadedness
- Fever higher than 101F (38.3C)
- Irregular heartbeat
- Shortness of breath
Your doctor may recommend certain steps to prevent or reduce your symptoms including:
- Drinkingmore fluids
- Getting up slowly after sitting or lying down
- Not drinkingalcohol
- Notstanding for a long time (if you have NMH)
- Using compression stockingssoblood does not collect in the legs
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Cheshire WP Jr. Autonomic disorders and their management. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed.Philadelphia, PA: Elsevier Saunders; 2011:chap 427.
Olgin JE. Approach to the patient with suspected arrhythmia. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed.Philadelphia, PA: Elsevier Saunders; 2011:chap 62.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.