Our blood pressure varies as we change our body positions. If we sit up from a supine position or stand, for a few seconds our blood pressure can drop a little. If that drop in blood pressure is significant, it may cause symptoms such as lightheadedness, dizziness, or fainting, which is called orthostatic hypotension. Normally, there are sensors in place to judge any drop in blood pressure and mechanisms available (like increasing the heart rate or constriction of blood vessels) to adjust it accordingly. Orthostatic hypotension happens when one or more of these corrective mechanisms fail.
How common is orthostatic hypotension?
It is quite common affecting 20-25% of people. Though it can affect young adults too, its risk increases with aging.
What are the symptoms of orthostatic hypotension?
Its symptoms include lightheadedness type of dizziness, lethargy, fatigue, falls, leg weakness, gait disorder, fainting, confusion, forgetfulness, neck and shoulder pain, shortness of breath, chest pain, tremor, and convulsions.
What are different causes of orthostatic hypotension?
Following are some of the main causes of this condition:
- Pump failure: The heart is the pump maintaining pressure in our arteries. Many conditions can cause its malfunction, such as problem with its rhythm or muscles, or cardiomyopathy.
- Stiff pipes: As we grow older, we lose elasticity in our arteries resulting in lack of corrective measures arteries can take to maintain blood pressure.
- Low volume: Dehydration or significant blood loss.
- Failure of pressure sensors: There are pressure sensors in our body (e.g., in carotid arteries) sensing low or high blood pressure. They help to make appropriate adjustment in pressure when the body changes its position. Failure of these sensors may lead to lack of corrective response and drop in blood pressure.
- Faulty wiring: Signal transmission through nerves is important to convey signals required to make corrective changes in blood pressure. Many types of nerve diseases or neuropathies affecting different type or size of nerves may cause this condition. One common example is diabetic neuropathy.
- Failure of central control: The whole system of blood pressure control is centrally controlled in the brain. Many brain conditions can affect this central control resulting in lack of pressure adjustment and low blood pressure.
- Outside factors: Finally, outside factors like drugs we take for medical conditions may also cause this condition.
Are there different types of orthostatic hypotension?
For better understanding, it can be divided in different types, which can be done in more than one way:
1: Based upon the cause:
- Cardiogenic, when the cause is in the heart
- Hemodynamic, when the cause is in the blood vessels
- Neurogenic, when the cause is neurological. This type is discussed in a bit more detail underneath.
- Endocrinological, caused by an underlying hormonal problem
- Iatrogenic, caused by medicines or medical interventions
2: Based upon its clinical features:
- Initial: When the drop in blood pressure and associated symptoms appear soon after standing and may fully recover in a matter of few seconds (15 sec).
- Delayed recovery: When the drop in blood pressure and associated symptoms take longer time to resolve (30-60 seconds).
- Classic: When the drop in blood pressure and associated symptoms continue for minutes to hours after standing.
- Delayed onset: When the drop in blood pressure and associated symptoms appear late after standing, after minutes.
Why neurogenic orthostatic hypotension is different from others?
In neurogenic orthostatic hypotension the cause is primarily neurological, and there are many such causes. Some are outlined underneath:
- Problem originating in the nervous system, e.g.:
- Problem in the brain
- Multi-system atrophy
- Parkinson
- Lewy-body dementia
- Autonomic failure
- Problems originating outside the nervous system, e.g.:
- Diabetic neuropathy
- Toxic neuropathy
- Autoimmune neuropathy
- Gillian-Barre syndrome
- Spinal cord issues, e.g.:
- Traumatic injury
- Multiple Sclerosis
- Stroke
What are some common peculiar features of neurogenic orthostatic hypotension?
. Limited increase in heart rate when needed
. Standing hypotension and supine hypertension
How is orthostatic hypotension diagnosed?
History taking is critical as routine blood pressure measurements can be deceivingly normal or inconclusive unless this condition is suspected, and appropriate techniques are used. History can also help to differentiate it from other similar conditions. In most cases, it can be easily diagnosed by taking blood pressure measurements in supine or flat position and then sitting or standing (preferred) position. Drop in systolic blood pressure of 20-40 degrees or more is considered diagnostic.
It is important to mention that not able to find the drop in blood pressure in bedside testing does not rule out orthostatic hypotension, especially if the history is suggestive. In such cases, more frequent or prolonged period of blood pressure measurements can help. In more difficult cases, formal autonomic testing can be requested.
What is autonomic testing?
Autonomic part of our nervous system automatically controls our organ systems, including heart and blood vessels. There are many ways to assess function of the autonomic nervous system. For purpose of diagnosing orthostatic hypotension and to differentiate it from some other similar conditions, a Tilt table test can be employed. In this test, the patient lies flat on a table and the table is tilted up and down with continuous blood pressure and heart rate monitoring.
How to diagnose neurological orthostatic hypotension?
In bedside testing, checking heart rate and blood pressure can help. If the nervous system or the autonomic nervous system is intact, standing from supine position may lead to drop in blood pressure but increase in heart rate, which might be less or absent in neurogenic cause of orthostatic hypotension. Another way is to measure blood norepinephrine level in supine and standing position.
What is the prognosis for orthostatic hypotension?
Orthostatic hypotension is not a benign disorder, and its prognosis is variable at best. It can significantly impact patient’s quality of life. At minimum, it is a cause of dizziness or lightheadedness. It may lead to falls and physical injuries. It may negatively impact multiple organs including the heart, kidneys, eyes, and brain. It also leads to decreased life expectancy especially in neurological orthostatic hypotension.
Is there a cure for orthostatic hypotension?
In some situations, it can be fully treated. For example, dehydration can be reversed, and some heart conditions can be fixed. In many other conditions, there is no cure, and a patient must learn to safely live with it.
What measures a patient can take to avoid symptoms of orthostatic hypotension?
The foremost is to understand the condition and how it can cause injury or affect different organ systems. Following non-medicinal measures can help:
- Pay attention to proper hydration especially in very hot and cold climates.
- While waking up, take it easy. Sit on the bedside for a few seconds before getting up.
- Keep a glass of water on bedside before sleeping and drink it before getting out of bed after a full night’s sleep.
- Consider sleeping on ground floor and avoid stairs upon waking up before drinking enough water.
- Avoid caffeinated beverages before drinking a glass or two of water. Drink 2-3 glasses of water in the morning before the tea or the coffee.
- While sleeping, keep the head end of the bed or the head little elevated. This is because patients may have low blood pressure while sitting or standing but they might also have high blood pressure in supine position, especially if they are taking some medicines to treat this condition. To avoid complications, some patients might have to significantly elevate the head end of the bed.
- Avoid prolonged standing, especially after exercise. If standing is required, make sure to hold onto something, or cross your leg and tense leg muscles. In case dizziness happens, sit, or lay down.
- Avoid alcohol, it could make things worse in many ways.
- While standing, keep stretching calf and leg muscles, or cross your legs, which helps to pump blood towards the heart.
- Wear tight stockings or the Ted stockings to avoid pooling of blood in legs.
- Do regular exercise to strengthen leg and body musculature, which helps to push blood upwards.
- Review all your medicines and consider stopping or decreasing the dose of the meds that may drop blood pressure.
- Avoid heavy meals, especially heavy carbohydrate meals. Instead, consider smaller more frequent meals. On the other hand, patients who have low BP during daytime and high during sleep, it is better to drink a glass of water or a sweetened drink at bedtime
- Avoid constipation, as straining could result in dizziness and fainting.
- Avoid delaying urination too much or until the bladder is very full. Urination after the bladder is full can also result in low blood pressure, dizziness, and fainting.
- Avoid urination in a standing position.
- Take a shower in sitting position in a shower chair. If feeling dizzy, avoid the soaking tub. Similarly, avoid swimming alone. You may be able to enjoy swimming but coming out of water could be tricky and can result in dizziness. Use the pool stairs and take it easy.
- If going out or if the environment is too dry or hot, carry a bottle or two of water. If any sign of dizziness happens, drink the water.
- Don’t monitor your blood pressure too much, rather monitor your symptoms. It matters less if blood pressure is on the lower side, but symptoms are controlled.
- Review all your meds with your doctor. Many medicines such as beta-blockers, alpha-blockers, or tricyclics are used for many different reasons, and they may make this condition worse.
- If your job involves prolonged standing, like a lecturer or a lawyer, consider sitting.
- For patients with this condition, it is better to avoid low sodium diet. Instead, if there is no other issue (and that can be clarified by your doctor), take some extra salt. Some patients may require taking salt tablets. Taking extra salt can help to increase blood volume, which helps to avoid low blood pressure. Patients with heart disease and high nighttime blood pressure should be more careful about salt intake and should discuss it with their doctor.
- While choosing exercise regimen, opt for exercise to improve leg lower body strength while avoiding having symptoms during exercise. Exercising in supine position can be helpful. Be careful at the end of exercise and avoid standing right away. While walking or hiking, carry a hiking pole or a stick. Keep a water bottle close by.
- Compression stockings and compression bands around the abdomen, like the coresets, are cumbersome to wear, especially in hot weather, and are marginally effective.
Which patient may require medicines for treatment of orthostatic hypotension?
Medicines can be prescribed for patients who fail or unable to undertake above-described non-pharmacological interventions. A well-educated and committed patient may do as well with the precautions and interventions described above.
What medicines are available for orthostatic hypotension?
Following are different classes of medicines with their mechanisms:
- Volume expanders: This type of medicines help to increase blood volume in the blood vessels and by doing so decrease chances of low blood pressure. Natural salt or sodium chloride being a natural product, does the same. If that is not enough, Fludrocortisone can be used. Max dose is 0.2mg a day. Conversely, it can cause night-time or supine high blood pressure and kidney and heart problems.
- Arterial constrictors: This type of medicines constrict smaller arteries (arterioles), which leads to elevation of blood pressure. Common example is Midodrine. They have short half-life, and 2-3 doses are required for proper control of symptoms. Dose is 2.5-15mg 2-3 times a day. Side effects include supine high blood pressure, itching, and goose bumps.
- Drugs that are converted into norepinephrine: This type of medicines get converted inside the body into norepinephrine hormone, which leads to high blood pressure. For example, Droxidopa, which is a short acting drug and 2-3 doses (100-600mg) a day are needed. Typical side effects are supine high blood pressure, headache, and fatigue.
- Drugs that slow down natural decay of norepinephrine: For example, Atomoxetine, is a short-acting, with dose of 10-18 mg twice a day. Side effects can be supine high blood pressure, insomnia, irritability, and decreased appetite.
- Drugs that slow down carbohydrate absorption: For example, Acarbose, can slow down sugar absorption after eating and is reasonable solution for post-prandial hypotension. Dose is 50-150mg before meals. Side effects are bloating and gas.
- Miscellaneous: Pyridostigmine can help to increase blood pressure and symptoms of orthostatic hypotension, especially if it is used in combination with another agent like midodrine. Dose is 30-60mg 2-3 times a day. Side effects can be diarrhea, excessive salivation, abdominal cramping, sweating, and urinary incontinence.
It is important to mention that despite their widespread use, not all these drugs are approved by FDA to treat orthostatic hypotension, but droxidopa and midodrine are FDA approved.
What type of doctor do I need to see if I have orthostatic hypotension?
It depends upon its root cause. Many such cases are managed by general medical doctors or the primary care providers. Many patients are seen by cardiologists, and many others by neurologists. Some may also be seen by an endocrinologist.
Where can I find more information about orthostatic hypotension?
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