Introduction:
While standing, gravity pulls blood down away from the brain, causing arterial pressure to drop. Ordinarily, this drop is transient, lasting only through a few cardiac cycles. If an individual lacks the necessary circulatory reflexes or blood volume upon standing, less blood and oxygen will reach the brain. This is manifested by dizziness or syncope and increases the patient’s fall risk. The baroreceptor reflex normally kicks in to compensate for standing. Baroreceptors located in the vessels of the chest and carotid send a decrease in blood pressure that will lead to an increase in vasoconstriction and an increase in heart rate to bring blood pressure back up. In the longer term, epinephrine levels and antidiuretic hormone increase in the blood to help maintain blood pressure while standing.
What Are the Causes of Orthostatic Hypotension?
Some of the causes of orthostatic hypotension are mentioned below-
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Hypovolemia (Reduced Volume in the Vascular Compartment)- Blood pressure may be sufficient when the person is sitting or lying down, but while standing, they can get lightheaded. Some causes of hypovolemia may include inadequate fluid intake, excessive urination, excessive use of diuretics, excessive sweating, loss of fluid by vomiting or diarrhea, and loss of fluid from prolonged bed rest. Heart conditions such as heart attack, heart failure, and bradycardia also decrease the cardiac output necessary to overcome the pull of blood away from the brain while standing up. Issues like hypothyroidism or low cortisol levels, such as with Addison's disease, can lower blood pressure and blood volume, putting a patient at risk for postural hypotension. Diabetes can also damage the neurons important in the feedback loop for increasing blood pressure while standing.
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Side Effects of Drugs- Many medications have side effects of postural hypotension and increase the risk of patient falls. Medications used for hypertension and angina fall into this category, including alpha-blockers, angiotensin-converting enzyme (ACE) inhibitors, nitrates, calcium channel blockers, and beta blockers. Other medications that may cause orthostatic hypotension includes drugs used for erectile dysfunction (Sildenafil), sedatives or anti-anxiety drugs (Benzodiazepines), hypnotic drugs (Zolpidem, Diphenhydramine), muscle relaxants (Cyclobenzaprine), antidepressants, dopaminergic agents (Levo-Dopa), antipsychotics, anticholinergics (Oxybutynin), opioids (Morphine), and cardiac glycosides (Digoxin).
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Nervous System Complications- Peripheral neuropathy with diabetes mellitus, spinal cord injury, and cerebral vascular accidents such as stroke can all impair autonomic nervous system reflexes necessary to maintain blood pressure upon standing. In neurodegenerative conditions such as Lewy body dementia, amyloidosis, Parkinson's disease, and shy-drager syndrome, the autonomic nervous system may fail and bring orthostatic hypotension.
What Role Does Orthostatic Hypotension Play in Aging?
Orthostatic hypotension can become a more severe problem with increasing age. This is due to a decrease in the activity of compensatory mechanisms like the baroreceptor reflex. Elderly persons also have reduced blood volume and reduced skeletal pump function, which further complicates the problems. After the age of 70 years, patients are more likely to experience postural hypotension due to the aging process, and this is the most often systolic dysfunction that causes a decrease in blood flow to the brain.
Elderly patients are also more prone to taking antihypertensive medications or diuretics, further complicating the problem. In addition to dizziness, the patient may experience weakness and ataxia, including gait and speech abnormalities. It is important to treat and prevent orthostatic hypotension, especially in the elderly, because fluctuations in the blood pressure to the brain increase the risk for stroke and complications of cardiovascular disease like angina, heart failure, and arrhythmias.
How Orthostatic Hypotension is Diagnosed?
It is important to take a thorough medical history, including a history of syncope and falls, medication history, and other medical conditions.
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Blood pressure is measured when the patient is supine, sitting, or standing. Symptoms while being in these different positions will be noted. Diagnostic criteria for orthostatic hypotension are decreased systolic pressure of at least 20 millimeters of mercury (mm Hg) or decreased diastolic pressure of at least 10 millimeters of mercury during the first three minutes of standing.
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Blood tests for hypovolemia and anemia may be performed.
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An EKG or echocardiogram may be performed to test for cardiac arrhythmias and for structural changes in the heart, such as valvular diseases. These tests may be performed while walking on a treadmill to determine heart function under tests.
How to Manage Orthostatic Hypotension in Older Patients?
Treatment in older patients focuses on determining the underlying cause first; for example, it may involve certain medications or vitamin supplements that the patient is taking. Important lifestyle modifications for patients include:
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Standing up slowly to allow the negative feedback mechanisms to kick in while going from a supine position to a standing position.
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It is also helpful to sit on the edge of the bed for a moment before standing up and, while doing so, contract the calf muscles to increase the blood return to the heart. If symptoms appear while standing, contract thigh muscles or rise up on your toes to contract the calf muscles.
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If one needs to bend down to pick something up, it is advisable not to bend down from the waist instead, squatting while bending the knees is beneficial.
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Using pillows to elevate the head while sleeping will decrease the chance of hypotension while getting up.
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It is important to avoid things or conditions that can cause too much vasodilation, such as drinking alcohol or intense exercise in hot environments or saunas.
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Be aware of what may lead to dehydration, including diaphoresis, lack of fluid intake, and vomiting or diarrhea.
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Support clothes or abdominal support clothing can be used to keep blood pressure from pooling in the legs and abdomen. These supporting garments should be taken off while lying down.
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Eating smaller meals may be necessary for those who may have a drop in blood pressure after meals. Also, measures should be taken to increase the vascular volume, such as increased salt in the diet but should be done in moderation and with physician approval.
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Several medications may be used to treat orthostatic hypotension when lifestyle modifications are not working and are prescribed by a physician.
Conclusion:
Orthostatic hypotension is a common condition that can be encountered daily by an older person and drastically impacts their quality of life and results in rapid deterioration in physical and social activities. When diagnosed, it should not be ignored, and the patient should seek medical attention. One can easily manage this condition with proper lifestyle modification and treatment options, which can significantly impact maintaining independence in older people.
