What is postural hypotension
Postural hypotension also called orthostatic hypotension, is defined as a sudden drop in blood pressure upon standing from a sitting or lying down position 1). Postural hypotension can make you feel dizzy or lightheaded, and maybe even faint. Clinically, postural hypotension is diagnosed by a sustained reduction in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of 10 mmHg within three minutes of standing after being supine for five minutes or at a 60-degree angle on the tilt table 2). This sudden drop in blood pressure is usually secondary to failure of autonomic reflex, volume depletion (hypovolemia) or adverse reaction to medication. Symptoms on presentation are commonly related to cerebral hypoperfusion, but patients can also be asymptomatic. There also is a high rate of morbidity and mortality related to this disease process due to frequent falls, which can lead to multiple hospital admissions 3).
Postural hypotension may be mild and last for less than a few minutes. However, long-lasting postural hypotension can signal more-serious problems, so it’s important to see a doctor if you frequently feel lightheaded when standing up.
According to the literature, postural hypotension is most prevalent in patients age 65 years or older, in part due to impaired baroreceptor sensitivity. The prevalence can be as high as 18.2% within that age range. Patients with cardiovascular disease such as aortic stenosis, pericarditis/myocarditis or arrhythmias are also at increased risk for postural hypotension. It can also occur in younger and middle-age patients, who, in the absence of volume depletion, usually have a chronic autonomic failure.
Occasional (acute) postural hypotension is usually caused by something obvious, such as dehydration or lengthy bed rest, and is easily treated. Chronic orthostatic hypotension is usually a sign of another health problem, so treatment varies.
When postural hypotension is caused by hypovolemia due to medications, postural hypotension may be reversed by adjusting the dosage or by discontinuing the medication. When postural hypotension is caused by prolonged bed rest, improvement may occur by sitting up with increasing frequency each day. In some cases, physical counterpressure such as elastic hose or whole-body inflatable suits may be required. Dehydration is treated with salt and fluids. More severe cases can be treated with drugs, such as midodrine, to raise blood pressure.
Postural hypotension causes
When you stand up, gravity causes blood to pool in your legs and abdomen. There is pooling of approximately 300 mL to 800 mL of blood in the lower extremities secondary to gravitational forces immediately upon standing from a supine position. This decreases blood pressure because there’s less blood circulating back to your heart.
Normally, special cells (baroreceptors) near your heart and neck arteries sense this lower blood pressure. The baroreceptors send signals to centers in your brain, which signals your heart to beat faster and pump more blood, which stabilizes blood pressure. These cells also narrow the blood vessels and increase blood pressure. When patients lack this compensatory mechanism (the baroreceptor reflex), they present with symptoms of postural hypotension.
Postural hypotension occurs when something interrupts the body’s natural process of counteracting low blood pressure. Many different conditions can cause postural hypotension, including:
- Dehydration. Fever, vomiting, not drinking enough fluids, severe diarrhea and strenuous exercise with excessive sweating can all lead to dehydration, which decreases blood volume. Mild dehydration can cause symptoms of postural hypotension, such as weakness, dizziness and fatigue.
- Heart problems. Some heart conditions that can lead to low blood pressure include extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure. These conditions prevent your body from responding rapidly enough to pump more blood when standing up.
- Endocrine problems. Thyroid conditions, adrenal insufficiency (Addison’s disease) and low blood sugar (hypoglycemia) can cause postural hypotension, as can diabetes — which can damage the nerves that help send signals regulating blood pressure.
- Nervous system disorders. Some nervous system disorders, such as Parkinson’s disease, multiple system atrophy, Lewy body dementia, pure autonomic failure and amyloidosis, can disrupt your body’s normal blood pressure regulation system.
- After eating meals. Some people experience low blood pressure after eating meals (postprandial hypotension). This condition is more common in older adults.
Postural hypotension can be caused by both neurogenic and non-neurogenic etiologies and can also be related to medication. Neurogenic postural hypotension is characterized by autonomic instability secondary to neuropathic disease, neurodegenerative disease, or aging. Neuropathic diseases include diabetes, cholinergic receptor autoantibodies, and familial dysautonomia. Neurodegenerative diseases include Parkinson disease, multiple-system atrophy, and pure autonomic failure. Non-neurogenic postural hypotension is most commonly due to volume depletion. One must also consider medication induced postural hypotension particularly in the case of polypharmacy in the elderly.
Risk factors for postural hypotension
The risk factors for postural hypotension include:
- Age. postural hypotension is common in those who are age 65 and older. Special cells (baroreceptors) near your heart and neck arteries that regulate blood pressure can slow as you age. It also may be harder for an aging heart to beat faster and compensate for drops in blood pressure.
- Medications. These include medications used to treat high blood pressure or heart disease, such as diuretics, alpha blockers, beta blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors and nitrates. Other medications that may increase your risk of postural hypotension include medications used to treat Parkinson’s disease, certain antidepressants, certain antipsychotics, muscle relaxants, medications to treat erectile dysfunction and narcotics. Using medications that treat high blood pressure in combination with other prescription and over-the-counter medications may cause low blood pressure.
- Certain diseases. Some heart conditions, such as heart valve problems, heart attack and heart failure; certain nervous system disorders, such as Parkinson’s disease; and diseases that cause nerve damage (neuropathy), such as diabetes, increase the risk of low blood pressure.
- Heat exposure. Being in a hot environment can cause heavy sweating and possibly dehydration, which can lower your blood pressure and trigger postural hypotension.
- Bed rest. If you have to stay in bed a long time because of an illness, you may become weak. When you try to stand up, you may experience postural hypotension.
- Pregnancy. Because your circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. This is normal, and blood pressure usually returns to your pre-pregnancy level after you’ve given birth.
- Alcohol. Drinking alcohol can increase your risk of postural hypotension.
Postural hypotension symptoms
The most common symptom is lightheadedness or dizziness when you stand up after sitting or lying down. Symptoms usually last less than a few minutes.
Postural hypotension signs and symptoms include:
- Feeling lightheaded or dizzy after standing up
- Blurry vision
- Fainting (syncope)
Postural hypotension complications
Persistent postural hypotension can cause serious complications, especially in older adults. These include:
- Falls. Falling down as a result of fainting (syncope) is a common complication in people with postural hypotension.
- Stroke. The swings in blood pressure when you stand and sit as a result of postural hypotension can be a risk factor for stroke due to the reduced blood supply to the brain.
- Cardiovascular diseases. postural hypotension can be a risk factor for cardiovascular diseases and complications, such as chest pain, heart failure or heart rhythm problems.
Postural hypotension diagnosis
Your doctor’s goal in evaluating postural hypotension is to find the underlying cause, and determine appropriate treatment for any health problems that may cause your low blood pressure. The cause isn’t always known.
Your doctor may review your medical history, review your symptoms and conduct a physical examination to help diagnose your condition.
Your doctor also may recommend one or more of the following:
- Blood pressure monitoring. Your doctor will measure your blood pressure both while you’re sitting and while you’re standing and will compare the measurements. Your doctor will diagnose postural hypotension if you have a drop of 20 millimeters of mercury (mm Hg) in your systolic blood pressure or a drop of 10 mm Hg in your diastolic blood pressure within two to five minutes of standing up, or if standing causes signs and symptoms.
Blood tests. These can provide information about your overall health, including low blood sugar (hypoglycemia) or low red blood cell levels (anemia), both of which can cause low blood pressure.
- Electrocardiogram (ECG or EKG). This noninvasive test detects irregularities in your heart rhythm or heart structure, and problems with the supply of blood and oxygen to your heart muscle. During this painless, noninvasive test, soft, sticky patches (electrodes) are attached to the skin of your chest, arms and legs. The patches detect your heart’s electrical signals while a machine records them on graph paper or displays them on a screen. Sometimes, heart rhythm abnormalities come and go, and an ECG won’t find any problems. If this happens, you may be asked to wear a 24-hour Holter monitor to record your heart’s electrical activity as you go about your daily routine.
- Echocardiogram. In this noninvasive exam, sound waves are used to produce a video image of your heart. Sound waves are directed at your heart from a wandlike device (transducer) that’s held on your chest. The sound waves that bounce off your heart are reflected through your chest wall and processed electronically to provide video images of your heart in motion to detect underlying structural heart disease.
- Stress test. A stress test is performed while you’re exercising, such as walking on a treadmill. Or you may be given medication to make your heart work harder if you’re unable to exercise. When your heart is working harder, your heart will be monitored with electrocardiography, echocardiography or other tests.
- Tilt table test. A tilt table test evaluates how your body reacts to changes in position. You’ll lie on a flat table that tilts to raise the upper part of your body, which simulates the movement from a horizontal to standing position. Your blood pressure is taken frequently as the table is tilted.
- Valsalva maneuver. This noninvasive test checks the functioning of your autonomic nervous system by analyzing your heart rate and blood pressure after several cycles of a type of deep breathing: You breathe in deeply and push the air out through your lips, as if you were trying to blow up a stiff balloon.
Postural hypotension treatment
The goal of treatment for postural hypotension is to restore normal blood pressure. That usually involves increasing blood volume, reducing the pooling of blood in your lower legs and helping blood vessels to push blood throughout your body.
Treatment often addresses the underlying cause — dehydration or heart failure, for example — rather than the low blood pressure itself.
For mild postural hypotension, one of the simplest treatments is to sit or lie down immediately after feeling lightheaded upon standing. Your symptoms should disappear.
When low blood pressure is caused by medications, treatment usually involves changing the dose of the medication or stopping it entirely.
Postural hypotension treatments include:
- Lifestyle changes. Your doctor may suggest several lifestyle changes, including drinking enough water; drinking little to no alcohol; avoiding overheating; elevating the head of your bed; avoiding crossing your legs when sitting; and standing up slowly. If you don’t also have high blood pressure, your doctor might suggest increasing the amount of salt in your diet. If your blood pressure drops after eating, your doctor may recommend small, low-carbohydrate meals.
- Compression stockings. Compression stockings and garments or abdominal binders may help reduce the pooling of blood in your legs and reduce the symptoms of postural hypotension.
Several medications, either used alone or together, can be used to treat postural hypotension. For example, the drug fludrocortisone is often used to help increase the amount of fluid in your blood, which raises blood pressure. Midodrine raises standing blood pressure levels by limiting expansion of your blood vessels, which in turn raises blood pressure. Droxidopa (Northera) may be prescribed to treat postural hypotension associated with Parkinson’s disease, multiple system atrophy or pure autonomic failure.
Other medications, such as pyridostigmine (Regonol, Mestinon), nonsteroidal anti-inflammatory drugs (NSAIDs), caffeine and epoetin (Epogen, Procrit, others), are sometimes used, too, either alone or with other medications for people who aren’t helped with lifestyle changes or other medications.
Lifestyle and home remedies
Some simple steps help manage or prevent postural hypotension. Your doctor may give you several suggestions, including:
- Increase salt in your diet. This must be done carefully and only after discussing it with your doctor. Too much salt can cause your blood pressure to increase beyond a healthy level, creating new health risks.
- Eat small meals. If your blood pressure drops after eating, your doctor may recommend small, low-carbohydrate meals.
- Ask about vitamin supplements. Both anemia and vitamin B-12 deficiency can affect blood flow and worsen symptoms of postural hypotension, so iron and vitamin supplements might be helpful for you if you’re deficient.
- Get plenty of fluids. Keeping hydrated helps prevent symptoms of low blood pressure. Drink plenty of water before long periods of standing, or any activities that tend to trigger your symptoms.
- Avoid alcohol. Alcohol can worsen postural hypotension, so limit or avoid it completely.
- Exercise. Regular cardiovascular and strengthening exercises may help reduce symptoms of postural hypotension. Avoid exercising in very hot, humid weather. Stretch and flex your calf muscles before sitting up. If symptoms strike, squeeze your thigh, abdominal and buttock muscles. Squat, march in place or rise onto your tiptoes.
- Avoid bending at the waist. If you drop something on the floor, squat with your knees to recover it.
- Wear waist-high compression stockings. These may help improve blood flow and reduce the symptoms of postural hypotension. Wear them during the day, but take them off for bed and anytime you lie down.
- Get up slowly. You may be able to reduce the dizziness and lightheadedness that occur with postural hypotension by moving slowly from a lying to standing position. Also, when getting out of bed, sit on the edge of your bed for a minute before standing.
- Elevate your head in bed. Sleeping with the head of your bed slightly elevated can help fight the effects of gravity.
- Move your legs while standing. If you begin to get symptoms while standing, cross your thighs in a scissors fashion and squeeze, or put one foot on a ledge or chair and lean as far forward as possible. These maneuvers encourage blood to flow from your legs to your heart.
Postural hypotension prognosis
The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.
References [ + ]
|1, 2.||↵||Ringer M, Lappin SL. Orthostatic Hypotension. [Updated 2019 Mar 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448192|
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