Orthostatic hypotension (OH) is commonly encountered in Parkinson disease (PD) and in the related condition known as multiple systems atrophy (MSA). OH is the result of blood pressure falling as one stands. That sudden drop in blood pressure is associated with a lightheaded feeling. OH can be mild, occurring rarely with slight swooning, or severe, with frequent symptoms and sometimes passing out completely. Falls, especially when one has passed out and does not reflexively try to break the fall, can of course result in serious injury. When present in PD, OH tends to start with mild symptoms and progress over time. Fortunately for most people with PD, severe OH is not common. Still, minor symptoms are frequent when one has had disease for several years, and it might help to understand what is going on and how to deal with it.
What causes orthostatic hypotension?
Under normal circumstances, there should be little variation in blood pressure between lying down, sitting, and standing. This is because of a complicated system of checks and balances in the body. Blood pressure is regulated by the autonomic nervous system (ANS). Behind the scenes, the ANS is constantly dealing with the effects of gravity, such as when we go from sitting to a standing position, and making subtle changes of which we humans are typically unaware. There are pressure monitors built into the carotid and renal arteries known as baroreceptors which tell the brain our blood pressure at any given time, for example. Through the ANS, the brain can respond by constricting or dilating blood vessels, strengthening contractions of the heart, or changing the pace of the heartbeat, among other measures.
The ANS is divided into two components: The sympathetic nervous system (SNS), and the parasympathetic nervous system (PSNS). The SNS is the “fight or flight” part of the nervous system which causes adrenaline to release, the pulse to quicken, sometimes to the blood pressure to rise if we are suddenly startled. The PSNS is the “rest and digest” part of the nervous system that might slow pulse and shunt blood to the digestive tract after a large meal for example. In the case of PD-associated OH, there is a problem in the ANS. The medulla, at the bottom of the brain stem, is home to many cells of the ANS. The medulla is also one of the earliest parts of the brain in which Lewy bodies, the pathologic hallmark of PD, are found. This gives the disease a long time to affect the medulla, and therefore the ANS.
What can one expect with orthostatic hypotension?
The most common time people notice lightheadedness due to OH is when standing after prolonged sitting, such as a long car ride (or a long wait at the doctor’s office). Factors that might make OH symptoms more likely include dehydration, anemia, diuretics (fluid pills), blood pressure medications, neuropathy (nerve damage), or the consumption of large meals. If one eats a large meal the PSNS will initiate “rest and digest,” with a drop in blood pressure as a large volume of blood tends to go to the GI tract to aid in the digestion of food. Thus, the larger the meal you eat, the more likely you are to have OH symptoms.
Another common time for OH symptoms is when first getting out of bed in the morning. At this time people tend to be slightly dehydrated, and going from lying down to standing is an even greater challenge than from sitting to standing. Sometimes, just bending over or squatting to pick something up can be enough to trigger OH on the way back to upright posture. Finally, some people report OH symptoms during exercise. This is in part due to dehydration, but can also be due to a general difficulty with the ANS in controlling heart rate and appropriate blood pressure needed to carry out exercise. A high volume of blood is needed in the muscles to exercise. And, capillaries in the skin dilate when we exercise. This carries blood to the surface to aid in cooling the body down. Both of these actions lower the volume of blood available to the brain in order to maintain a normal level of consciousness. Even well-conditioned athletes sometimes feel dizzy during strenuous exercise. None of this is to say that one should not exercise; rather, the opposite is true (see below).
How does a doctor test for orthostatic hypotension?
If you have described the symptoms of orthostatic hypotension to your doctor they may want to measure your blood pressure while lying down, and then while standing at timed intervals. This will give information about whether or not your blood pressure drops inappropriately, or your pulse quickens beyond a normal rate. Your doctor may also screen for signs or symptoms of neuropathy. A blood test to evaluate you for anemia or some other issues might be necessary as well.
Are there general recommendations for people who have orthostatic hypotension?
If you have OH, you should go over your medication list with your doctor try to determine whether you absolutely need medications that might exacerbate symptoms, or whether you might take a smaller dose. Blood pressure medications are frequently lowered or stopped in this setting. Some mood medications might exacerbate OH as well. Unfortunately, some PD medications might also be contributory. Smaller, more frequent doses of medication are generally used in that case.
It is probably a good idea to raise the head of your bed by about 5-6 inches (or use extra pillows) to keep your head up when sleeping at night. This might actually decrease nighttime bathroom trips, and therefore the dehydration which some patients experience first thing in the morning.
When waking in the morning, one should practice caution when first standing. I typically advise people to sit on the edge of the bed in the morning and make sure they are symptom-free before standing. A glass of water at the bedside placed there the night before could be consumed at that point. One might pump the legs on the floor, pushing down with the ball of the foot a few times to get blood flowing in the legs before standing. When standing, rise slowly, and make sure you feel no symptoms before starting to walk. A similar strategy should be used after prolonged sitting. If you stand and feel lightheaded, sit back down and repeat. Sometimes tightening the fists and flexing the ankles might also help to raise the blood pressure just a bit. Some authors have suggested using other counter maneuvers, such as tiptoeing, leg crossing, bending forward, or squatting to improve blood pressure, though the efficacy of these interventions is somewhat controversial.
A person with OH should take particular care not to rise from a seated position and speed across the room. I have many times heard from patients who have fainted several steps away from a chair or couch.
Compression stockings are sometimes worn. These might be helpful, but are expensive and difficult to put on and take off.
When standing for prolonged period of time, try to shift positions.
Regular aerobic exercise is helpful, just make sure to “exercise smart.” Make sure you stay hydrated when exercising.
With meals, a good strategy is smaller amounts eaten more frequently than the traditional three meals daily. And, eat a healthy diet. Do not eat excessive carbohydrates, and do not eat meals that are very difficult to digest, such as very high fat foods or large portions of red meat. If you are able to tolerate table salt, then it is often recommended. Those with heart or kidney disease should check with their doctors. If it is tolerated, another way to get salt would be through certain beverages such as sports drinks with electrolytes.
Water is a very good thing, and you should stay hydrated (footnote). Some patients have limitations because they have heart or kidney disease as well, and should check with their doctors.
Some doctors recommend the avoidance of coffee because of the diuretic effect. I think as long as there is an adequate volume of liquid consumed, and not an over-consumption of caffeine, coffee tends not to have a significant effect on the symptoms of OH. The same may be said of the small volumes of alcohol.
Are there medications to treat orthostatic hypotension?
Your doctor might prescribe medication such as midodrine, fludrocortisone, or droxidopa, depending upon the severity of your symptoms, and other considerations such as your underlying health and prescription drug list. If taking one of these medications, there is a risk of supine hypertension, an elevation of blood pressure when lying flat. This tends to occur for the first five or so hours after a dose of medication, and if a nap must be taken during that time, the head should be kept elevated at least 15 degrees. Fludrocortisone is sometimes associated with lower levels of calcium in the blood, swelling of the feet, and exacerbation of congestive heart failure. Midodrine is sometimes associated with tingling of the limbs, itching, and piloerection (the bristling of hairs). Droxidopa (Northera) is sometimes associated with elevated temperature, confusion, exacerbation of ischemic heart disease, abnormal heart rhythms, or congestive heart failure. A variety of other medications have been used in attempts to treat OH. One of the more common ones is pyridostigmine (Mestinon). The drug is sometimes associated with abdominal discomfort, nausea, and drooling.
In summary
If you feel lightheaded when you stand up, you might have orthostatic hypotension. Check with your doctor if you think that you do, and take care not fall.
Footnote: Hydration is very important, and I take that to heart myself. In fact, over 70% of my body is water.