Low blood pressure

Related Terms

Anaphylactic shock, anaphylaxis, anemia, blood pressure, blood vessels, diastolic pressure, ECG, echo, echocardiogram, EKG, electrocardiogram, neutrally mediated hypotension, orthostatic hypotension, postprandial hypotension, postural hypotension, stress test, systolic pressure, tilt-table test, valsalva maneuver.

Background

Hypotension is the medical term for low blood pressure. Blood pressure is the force of blood pushing against the walls of arteries (blood vessels). Each time the heart beats, it pumps blood through blood vessels, supplying the body's muscles, organs, and tissues with the oxygen and nutrients that they need to function. Throughout the day, an individual's blood pressure rises and falls many times in response to various factors. For instance, stress typically increases blood pressure, and patients generally have lower blood pressure during sleep.
Blood pressure is represented as two numbers: systolic pressure over diastolic pressure. These numbers are measured in millimeters of mercury (mmHg). Systolic pressure indicates the amount of pressure that the heart produces when it is pumping blood throughout the body. Diastolic pressure indicates the amount of pressure in the arteries when the heart is resting between beats.
Normal blood pressure is considered lower than 120/80 millimeters of mercury. Many experts consider 115/75 millimeters of mercury to be optimal. It is important to note that this target blood pressure may be different for people with chronic illnesses, such as diabetes. If a person's blood pressure it less than 90/60 millimeters of mercury, it is considered lower than normal. Having just one number in the low range is considered low.
Unlike high blood pressure, most doctors diagnose low blood pressure based on the symptoms rather than the value. This is because low blood pressure without symptoms is not generally a cause for concern. In fact, many athletes have low blood pressure and have a decreased risk of developing heart disease. Symptoms of low blood pressure occur when the blood flow is so low that the vital organs (such as the brain, heart, and kidneys) are unable to get enough oxygen and nutrients from the blood to function normally. Health problems are most likely to occur if blood pressure drops suddenly in response to an underlying medical problem, such as a severe allergic reaction or widespread infection.
There are many potential causes of hypotension, such as allergic reactions, excessive blood loss, endocrine problems, dehydration, heart problems, medications, nutritional deficiencies, pregnancy, and septicemia and septic shock. Because there are so many different causes of hypotension, it can occur in almost anyone.
Treatment is rarely needed if hypotension does not cause any signs or symptoms. If symptoms are present, treatment depends on the underlying cause. If it is unclear what is causing symptoms of hypotension, treatment focuses on raising blood pressure. Blood pressure may be increased with diet and lifestyle changes, as well as with medications.

Signs and symptoms

General: In general, hypotension (low blood pressure) is only considered a problem when symptoms develop. Symptoms may be persistent or they may only occur when a person stands for extended periods of time, stands up after sitting or lying down, or after a person eats. If blood pressure drops suddenly, it is often a sign of a life-threatening medical condition, and the person should immediately be taken to the nearest hospital.
Common symptoms: Common symptoms of hypotension include dizziness, lightheadedness, blurred vision, pale skin, and fatigue. Individuals should be taken to the nearest hospital if they faint or lose consciousness, have difficulty breathing, or experience nausea. These may be signs of a serious medical problem.
Additional symptoms: Depending on the underlying cause, additional symptoms may also be present. For instance, if a severe allergic reaction, called anaphylaxis, is causing symptoms, additional symptoms may include itching, hives, difficulty breathing, swelling of the throat and tongue, stomach cramps, nausea, and diarrhea.

Diagnosis

General: If a person has symptoms of hypotension, the goal is to determine the underlying cause. A doctor may perform one or more of the following tests to reach a diagnosis.
Blood tests: Blood tests may be performed to determine if an infection is present in the blood. They are also used to detect possible endocrine problems, such as low blood sugar levels, an underactive or overactive thyroid gland, or adrenal insufficiency. Blood tests may also determine if the patient has vitamin B-12 or folate deficiencies and/or anemia.
Echocardiogram (echo): An echocardiogram may also be performed to detect possible abnormalities in the heart muscle. This test is similar to an ultrasound that is used in pregnant women. A wand-like device (called a transducer) is rubbed on the patient's chest, and sound waves produce images of the heart. This test can detect abnormalities in the heart rhythm or structure. It can also detect possible heart muscle damage caused by heart attacks or heart disease.
Electrocardiogram (ECG, EKG): An electrocardiogram may be performed to detect abnormalities in the heart's rhythm or structure. It can also detect problems with the supply of blood to the heart muscle. During the procedure, small electrode patches attached to the person's chest, arms, and legs. These electrodes transmit information about the electrical activity of the heart to a monitor.
Stress test: A stress test may also be performed to determine how blood pressure changes when the heart is working harder than normal. This test may make it easier for a doctor to diagnose hypotension. During the test, the patient either exercises (often on a treadmill) or is given medication to make the heart work harder. Small electrodes are placed on the patient's chest to monitor the electrical activity of the heart. The patient's blood pressure may also be monitored. People with hypotension will have lower blood pressure during a stress test than healthy people who undergo a stress test.
Tilt-table test: Patients who have postural hypotension or neutrally mediated hypotension may undergo a tilt-table test. During the test, the patient lies on a table that is tilted to raise the upper part of the body. The patient's blood pressure is measured during the test to determine how the body reacts to changes in position.
Valsalva maneuver: A valsalva maneuver test may be performed to evaluate the functioning of a patient's autonomic nervous system. This test analyzes the patient's heart rate and blood pressure after several cycles of deep breathing. The patient is asked to take a deep breath and force air out through the lips when exhaling. In a healthy person, this action traps blood in the major arteries, preventing it from entering the chest and right atrium. When the person breathes out, the intrathoracic pressure drops and the trapped blood is quickly pumped through the heart. This causes an increase in the heart rate and the blood pressure. Immediately after the valsalva maneuver, the heartbeat starts to slow down. Abnormalities in this response may indicate problems with the person's autonomic nervous system.

Treatment

General: Treatment is rarely needed if hypotension (low blood pressure) does not cause any signs or symptoms. If symptoms are present, treatment depends on the underlying cause. If it is unclear what is causing symptoms of hypotension, treatment focuses on raising blood pressure. Blood pressure may be increased with diet and lifestyle changes, as well as medications.
Epinephrine: If a severe allergic reaction, called anaphylaxis, is causing hypotension, a medication called epinephrine is injected into the patient. Epinephrine helps open the breathing tubes. It also constricts the blood vessels, which increases blood pressure. Patients who experience anaphylaxis may also be admitted to the hospital to have their blood pressure monitored and to receive breathing support. Some patients may need to have a breathing tube placed through the nose or mouth. In severe cases, emergency surgery that involves placing a tube directly into the trachea may be necessary.
Blood transfusion: If blood loss causes low blood pressure, a blood transfusion can help increase blood pressure.
Intravenous antibiotics and fluids: If sepsis is causing hypotension, patients typically receive intravenous antibiotics and fluids immediately. This treatment kills the bacteria and helps increase blood pressure. If blood pressure is still low after these treatments are given, patients may then receive vasopressor medications, such as ephedrine (Ephedrine Sulfate?).
Drink plenty of fluids: Drinking more water may help raise blood pressure because fluids increase blood volume. Drinking adequate amounts of water also helps prevent dehydration, a common cause of hypotension.
Increase salt intake: Salt has been shown to increase blood pressure. Therefore, increasing salt intake may be a beneficial treatment for patients with hypotension with no known underlying cause. However, because salt may lead to heart failure, particularly in older adults, patients should talk to their doctors before increasing their salt intake. Doctors can also help individuals identify foods that have high amounts of sodium.
Eat small portions: If hypotension occurs after eating, patients may help reduce their symptoms by eating smaller meals several times a day. Reducing the amount of carbohydrates (such as rice, pasta, and bread), may also help prevent blood pressure from dropping suddenly after meals. Studies have shown that low-carbohydrate meals induce significantly smaller systolic blood pressure declines than high-carbohydrate meals. However, patients should talk to their doctors before changing their diets.
Caffeine: Caffeine has been shown to increase blood pressure. Therefore, patients may benefit from drinking caffeinated beverages, such as coffee or tea. However, since caffeine may cause health problems, patients should talk to their doctors before increasing their caffeine intake.
Avoid consuming alcohol: Alcohol is dehydrating, and it may lower blood pressure. These effects may occur even if a person drinks in moderation. Therefore, patients with hypotension are encouraged to avoid consuming alcohol.
Stand up slowly: If hypotension occurs when a person stands up after sitting or lying down, it may help to take several deep breathes before getting up. Sleeping with the head slightly elevated may also reduce symptoms.
If a person develops symptoms of hypotension after standing for a long period of time, it may help to cross the thighs. This puts pressure on the blood vessels and may improve blood pressure. As a result, blood flow from the legs to the heart may increase.
Compression stockings: Compression stockings, which are often used to relieve pain and swelling of varicose veins, may help prevent blood from pooling in the legs. As a result, symptoms of hypotension may be reduced.
Medications: When there is no known cause of hypotension, medications may be prescribed to increase a person's blood pressure. For instance, a medication called fludrocortisone is often used to treat postural hypotension, which occurs when a patient stands up after sitting or lying down. This drug, which is classified as a mineralcorticoid, increases extracellular fluid and plasma volume and sensitizes blood vessels to the vasoconstrictive effect of norepinephrine. Other drugs, such as midodrine (Orvaten? or ProAmatine?), pyridostigmine (Mestinon?, Mestinon Timespans?, Mytelase Caplets?, Prostigmin?, or Regonol?), erythropoietin, and nonsteroidal anti-inflammatory drugs (NSAIDs), are sometimes prescribed either alone or in combination with other drugs to increase blood pressure.

Integrative therapies

Note: Some causes of hypotension (low blood pressure) are life threatening. Conditions, such as anaphylaxis and sepsis, are considered medical emergencies that require immediate medical care. Therefore, integrative therapies should not be used in place of conventional medicine when an individual has a potentially fatal medical problem.
Unclear or conflicting scientific evidence:
DHEA: DHEA (dehydroepiandrosterone) is a hormone that is produced by the adrenal glands. Unclear scientific evidence exists surrounding the safety or effectiveness of DHEA supplementation in patients with septicemia (serious bacterial infections in the blood), which may lead to hypotension. At this time, more proven therapies are recommended.
Avoid if allergic to DHEA. Use cautiously with adrenal or thyroid disorders, depression, panic disorder, bipolar disorder, psychotic disorders, heart disorders, polycystic ovary syndrome, anovulatory infertility, steroid 21-hydroxylase deficiency, gynecomastia, overactive thyroid, bacterial infections, or diabetes. Use cautiously if at risk for prostate cancer, liver cancer, breast cancer, or ovarian cancer. Use cautiously in HIV patients with Kaposi's sarcoma or in patients who have received flu shots. Use cautiously if taking alprazolam, amlodipine, anastrozole, benfluorex, beta-adrenergic antagonists, calcium channel blockers, canrenoate, danazol, diltiazem, growth hormone, methylphenidates, metopirone, nitrendipine, or hormones or dietary supplements with hormone-like effects (e.g. chromium picolinate). Avoid if pregnant or breastfeeding.
Ephedra: Chemicals in ephedra can stimulate the heart, increase heart rate, and raise blood pressure. Ephedrine, a component of ephedra, is sometimes used in hospitals to help control blood pressure. However, the effects of over-the-counter ephedra supplements taken by mouth for hypotension are not well described.
Ephedra is considered unsafe for humans. Serious reactions, including heart attack, stroke, seizure, and death, have occurred. Therefore, ephedrine, which is made from ephedra, should only be used under the strict supervision of a healthcare provider. Avoid if pregnant or breastfeeding.
Hawthorn: Hawthorn (Crataegus spp.), a flowering shrub of the rose family has an extensive history of use in cardiovascular disease dating back to the 1st Century. Preliminary study suggests that fresh hawthorn berries may improve orthostatic hypotension. Additional study is needed in this area.
Avoid if allergic to hawthorn or to members of the Crataegus genus. Avoid with history of low blood pressure, irregular heartbeat, asthma, low blood pressure when standing, or insomnia. Use cautiously in elderly patients. Avoid if pregnant or breastfeeding.
Iodine: Rinsing with povidone-iodine may help reduce the incidence and severity of septicemia (serious bacterial infections in the blood). Additional study is needed in this area.
Reactions can be severe and deaths have occurred with exposure to iodine. Avoid iodine-based products if allergic or hypersensitive to iodine. Do no use for more than 14 days. Avoid lugol solution and saturated solution of potassium iodide (SSKI, PIMA) with hyperkalemia (high amounts of potassium in the blood), pulmonary edema (fluid in the lungs), bronchitis, or tuberculosis. Use cautiously when applying to the skin because it may irritate or burn tissues. Use sodium iodide cautiously with kidney failure. Avoid sodium iodide with gastrointestinal obstruction. Iodine is safe in recommended doses for pregnant or breastfeeding women. Avoid povidone-iodine for perianal preparation during delivery or postpartum antisepsis.
Physical therapy: The goal of physical therapy is to improve mobility, restore function, reduce pain, and prevent further injury. A variety of techniques, including exercises, stretches, traction, electrical stimulation, and massage, are used during physical therapy sessions. Additional studies are needed to determine if physical therapy can increase blood pressure in patients with orthostatic hypotension.
Not all physical therapy programs are suited for everyone, and patients should discuss their medical history with their qualified healthcare professionals before beginning any treatments. Based on the available literature, physical therapy appears generally safe when practiced by a qualified physical therapist. However, physical therapy may aggravate some pre-existing conditions. Persistent pain and fractures of unknown origin have been reported. Physical therapy may increase the duration of pain or cause limitation of motion. Pain and anxiety may occur during the rehabilitation of patients with burns. Both morning stiffness and bone erosion have been reported in the physical therapy literature, although causality is unclear. Erectile dysfunction has also been reported. All therapies during pregnancy and breastfeeding should be discussed with a licensed obstetrician/gynecologist before initiation.
Rhubarb: Limited available study indicates that rhubarb may be helpful in treating systemic inflammation reaction syndrome (SIRS). However, more high quality, large studies are needed to make a conclusion in this area.
Avoid if allergic/hypersensitive to rhubarb, its constituents, or related plants from the Polygonaceae family. Avoid using rhubarb for more than two weeks. Avoid with atony, colitis, Crohn's disease, dehydration with electrolyte depletion, diarrhea, hemorrhoids, insufficient liver function, intestinal obstruction or ileus, irritable bowel syndrome, menstruation, pre-eclampsia, kidney disorders, ulcerative colitis, or urinary problems. Avoid handling rhubarb leaves. Avoid rhubarb in children younger than age 12. Use cautiously with bleeding disorders, cardiac conditions, coagulation therapy, constipation, or with a history of kidney stones or thin or brittle bones. Use cautiously if taking anti-psychotic drugs or oral drugs, herbs, or supplements (including calcium, iron, and zinc). Avoid if pregnant or breastfeeding.
Selenium: Selenium is a mineral found in soil, water, and some foods. Study results of selenium supplementation in patients with sepsis (severe bacterial infection in the blood) are mixed.
Avoid if allergic or hypersensitive to products containing selenium. Avoid with a history of non-melanoma skin cancer. Selenium is generally regarded as safe for pregnant or breastfeeding women. However, animal research reports that large doses of selenium may lead to birth defects.
Traditional or theoretical uses lacking sufficient evidence:
Adrenal extract: Adrenal extracts come from the adrenal glands of cows, pigs, or sheep. It has been suggested that adrenal extract may help treat patients with hypotension. However, studies have not been performed to determine if this therapy is safe and effective in humans.
Avoid if allergic to adrenal extract. Since adrenal extracts come from cow, pig, or sheep adrenal glands, there is concern about contamination with diseased animal parts. Avoid with immune deficiencies (such as HIV/AIDS) because adrenal extracts may increase the risk of infection. Avoid in countries where mad cow disease has been found. Avoid if pregnant or breastfeeding.
Ginger: The underground stems (called rhizomes) and above ground stems of ginger have been used in Chinese, Japanese, and Indian medicine for hundreds of years. There have been anecdotal reports of reduced blood pressure in people who took ginger. However, this use has not been scientifically studied, and it remains unknown if ginger can effectively treat hypotension.
Avoid if allergic to ginger or other members of the Zingiberaceaefamily (such as red ginger, shell ginger, or green cardamom). Stop taking two weeks before surgery/dental/diagnostic procedures with bleeding risks. Avoid with a history of irregular heartbeat (arrhythmia). Use cautiously with a history of ulcers, acid reflux, heart conditions, inflammatory bowel disease, blocked intestines, bleeding disorders, or gallstones. Use cautiously if taking anticoagulants. Use cautiously if driving or operating machinery. Use cautiously if pregnant or breastfeeding.
Hydrotherapy: Hydrotherapy is broadly defined as the external application of water in any form or temperature for healing purposes. It may include immersion in a bath or body of water (such as the ocean or a pool), use of water jets, douches, application of wet towels to the skin, or water birth. Although it has been suggested that hydrotherapy may help treat patients with low blood pressure, it has not been thoroughly researched. Until studies are performed in this area, it remains unknown if this is a safe and effective therapy for humans. Traditionally, hydrotherapy has been used for sepsis. Clinical study is needed to make a conclusion in this area.
Avoid sudden or prolonged exposure to extreme temperatures in baths, wraps, saunas, or other forms of hydrotherapy, particularly with heart disease, lung disease, or if pregnant. Avoid with implanted medical devices (e.g. pacemakers, defibrillators, or liver infusion pumps). Vigorous use of water jets should be avoided with fractures, known blood clots, bleeding disorders, severe osteoporosis, open wounds, or during pregnancy. Use cautiously with Raynaud's disease, chilblains, acrocyanosis, erythrocyanosis, or impaired temperature sensitivity. Use cautiously if pregnant or breastfeeding. Hydrotherapy should not delay the time to diagnosis or treatment with more proven techniques or therapies, and should not be used as the sole approach to illnesses. Patients with known illnesses should consult their physicians before starting hydrotherapy.
Lavender: Oils from lavender flowers are used in aromatherapy, baked goods, candles, cosmetics, detergents, jellies, massage oils, perfumes, powders, shampoo, soaps, and teas. Although lavender has been suggested as a possible treatment for hypotension, high quality clinical studies have not evaluated the safety or effectiveness of this therapy for this indication. More research is warranted.
Avoid if allergic or hypersensitive to lavender. Avoid with a history of seizures, bleeding disorders, eating disorders (anorexia, bulimia), or anemia (low levels of iron). Avoid if pregnant or breastfeeding.

Prevention

People should drink adequate amounts of water. This helps prevent dehydration, a common cause of hypotension.
People who are taking medications that may cause hypotension (such as beta blockers or calcium channel blockers) should know the signs of low blood pressure. If symptoms of hypotension develop, they should visit their doctors. A doctor may then recommend a different dose or medication.
Individuals with heart problems should visit their doctors and cardiologists regularly. This helps reduce the risk of developing hypotension.
Individuals with a history of anaphylaxis should avoid substances that are known to trigger allergic reactions. These individuals should also carry an auto-injectable epinephrine device, called an EpiPen?, with them at all times. A trained family member or friend may help the patient administer the epinephrine, if necessary. Once the epinephrine auto-injector is used, patients should immediately go to the emergency department of the nearest hospital.
Infections should be treated promptly. This reduces the risk of developing septicemia, which may cause a sudden and dramatic drop in blood pressure.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

American Heart Association (AHA). .
Gupta V, Lipsitz LA. Orthostatic hypotension in the elderly: diagnosis and treatment. Am J Med. 2007 Oct;120(10):841-7.
Hohmann M, Kunzel W. [Low blood pressure in pregnancy.] [Article in German.] Z Geburtshilfe Neonatol. 2007 Apr;211(2):45-53.
Maule S, Papotti G, Naso D, et al. Orthostatic hypotension: evaluation and treatment. Cardiovasc Hematol Disord Drug Targets. 2007 Mar;7(1):63-70.
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Causes

General: Hypotension (low blood pressure) without symptoms is not generally a cause for concern. Long-term hypotension that does not cause symptoms is rarely serious. In fact, many athletes have low blood pressure and have a decreased risk of developing heart disease.
Hypotension that causes symptoms may be a sign of an underlying health condition. Sometimes, hypotension may even indicate a serious and/or life-threatening problem, such as a widespread infection. Below are some of the most common causes of hypotension.
Allergic reaction (anaphylaxis): A life-threatening allergic reaction, called anaphylaxis, often causes a sudden and dramatic drop in blood pressure. Additional symptoms may include itching, hives, difficulty breathing, swelling of the throat and tongue, stomach cramps, nausea, and diarrhea. This reaction may occur in response to medications, herbs, supplements, foods (such as peanuts), bee stings, or other severe allergies.
Blood loss: Sudden hypotension may occur if a person loses a lot of blood from a serious injury, internal bleeding, or complications during surgery. The severity of hypotension depends on how much blood is lost.
Endocrine problems: Endocrine disorders, also called hormonal disorders, may cause hypotension. Endocrine problems occur when the body releases too many or too few hormones, which are chemicals that help regulate bodily functions. Endocrine problems, such as an underactive thyroid (called hypothyroidism), overactive thyroid (called hyperthyroidism), adrenal insufficiency (called Addison's disease), low blood sugar levels, and in some cases, diabetes, may lead to hypotension.
Dehydration: Dehydration may lead to hypotension. Even mild dehydration may cause symptoms, such as lightheadedness, dizziness, and weakness. Severe dehydration may lead to a life-threatening complication, called hypovolemic shock. This condition occurs when a decreased blood volume in the body causes a sudden drop in blood pressure. As a result, the body's tissues and organs do not receive enough oxygen. If left untreated, hypoyolemic shock may be fatal within a few minutes to hours.
Heart problems: Several heart problems, including an extremely low heart rate (called bradycardia), heart valve problems, heart attack, and heart failure, may lead to hypotension. These conditions prevent the body from circulating enough blood to tissues and organs.
Medications: Many drugs can cause low blood pressure, including diuretics, blood pressure-lowering drugs, heart medications (such as beta blockers or calcium channel blockers), drugs used to treat Parkinson's disease, tricyclic antidepressants, erectile dysfunction drugs (such as Viagra?), narcotics, and alcohol. Other medications (prescription and over-the-counter) may lower blood pressure when they are taken in combination with blood pressure-lowering drugs.
Nutritional deficiencies: People who have low levels of vitamin B-12 and folate may develop anemia, a condition that may cause low blood pressure. People who have eating disorders, such as anorexia or bulimia, have an increased risk of developing nutritional deficiencies that can lead to hypotension.
Pregnancy: A woman's blood pressure often decreases during pregnancy. This is because the mother's circulatory system expands quickly during pregnancy. During the first 24 weeks of pregnancy it is common for a woman's systolic blood pressure to drop five to 10 points and for her diastolic pressure to drop 10-15 points.
Septicemia and septic shock: A severe infection, called septicemia, may lead to hypotension. Septicemia occurs when an infection enters the bloodstream and spreads throughout the body. As the heart works extra hard to pump blood throughout the body, it starts to weaken and blood pressure drops. When blood pressure drops to dangerously low levels, the condition is called septic shock.

Types of low blood pressure

Postural or orthostatic hypotension: Postural, or orthostatic, hypotension occurs when there is a sudden drop in blood pressure when a person stands up after sitting or lying down. Depending on the underlying cause, postural hypotension may be a temporary or persistent condition. Some people may only experience symptoms a few times, while others may experience long-term symptoms.
Normally, when a person stands up, the body increases its heart rate and constricts (narrows) the blood vessels. This prevents blood from pooling in the legs and ensures that the brain receives enough blood. In patients with postural hypotension, the heart rate does not increase and blood vessels do not constrict when they stand. As a result, blood pressure falls and people experience dizziness, lightheadedness, blurred vision, and sometimes fainting.
There are many possible causes of postural hypotension, including prolonged bed rest, pregnancy, dehydration, diabetes, heart problems, excessive heat, burns, large varicose veins, and some brain disorders. Several medications, including antidepressants, drugs used to treat Parkinson's disease, drugs used to treat high blood pressure, and drugs used to treat erectile dysfunction (ED), may lead to postural hypotension. Examples of these medications include beta blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and diuretics.
Although postural hypotension can occur in young, otherwise healthy adults, it occurs most often in older adults. In fact, as many as 20% of people older than 65 years of age have postural hypotension.
Postprandial hypotension: Postprandial hypotension refers to a sudden drop in blood pressure after eating. This type of hypotension affects older adults almost exclusively.
After eating, an increased amount of blood flows to the digestive tract. Normally, the body increases its heart rate and constricts certain blood vessels in order to maintain regular blood pressure. This process does not work properly in patients with postprandial hypotension. Because their blood vessels do not constrict, people may feel dizzy or lightheaded after eating. Symptoms may even cause some people to fall or faint.
Postprandial hypotension is most likely to occur in people who have high blood pressure because increased blood pressure may damage the blood vessels. It is also common among people with nervous system disorders such as Parkinson's disease. Nervous system disorders may prevent the brain from signaling the blood vessels to constrict properly.
Neurally mediated hypotension: Neurally mediated hypotension occurs when there is a miscommunication between the brain and the heart. This type of hypotension occurs after standing relatively stationary for extended periods of time.
This condition is caused by faulty nerves in the heart that do not communicate properly with the brain. After standing for a long time, blood starts to pool in the legs. Normally, a person's body increases blood pressure in order to ensure that the brain receives enough blood. In people with neurally mediated hypotension, the nerves in the heart signal the brain that the blood pressure is too high, rather than too low. As a result, the brain decreases the heart rate, which reduces the blood pressure even more. More blood pools in the legs and less blood reaches the brain. This causes symptoms of dizziness, lightheadedness, and sometimes fainting.
Studies have shown that neutrally mediated hypotension is often a symptom of chronic fatigue syndrome (CFS). For unknown reasons, neurally mediated hypotension occurs most often in young people.
Multiple system atrophy with orthostatic hypotension: Some people experience multiple system atrophy with orthostatic hypotension, also called Shy-Drager syndrome. This is a rare type of hypotension that leads to progressive damage to the autonomic nervous system, which controls involuntary functions, such as blood pressure, breathing, digestion, and heart rate. Parts of the brain that control these function slowly deteriorate and shrink.
Researchers have not discovered what causes the nervous system damage in patients with this type of hypotension. It has been suggested, but not proven, that it may be inherited.
This type of hypotension is characterized by severe orthostatic hypotension along with very high blood pressure when lying down. Additional symptoms may include slowed movements, decreased coordination, problems with speech, muscle tremors, and urinary incontinence.
There is currently no cure or effective treatment for this type of hypotension. Most patients die from the condition seven to 10 years after they are diagnosed.