H I G H B L O O D P R E S S U R E
The heart pumps blood containing oxygen and other nutrients through the arteries to the rest of the body. Blood "pressure" is the force exerted on the arteries by the blood passing through them. It is determined by how much resistance there is in the arteries, and is not a measure of how "strong" the heart muscle is.
High blood pressure, or "hypertension", is a very common disorder. It is associated with an increased risk of coronary artery disease, stroke, heart attack, kidney failure, and death. Despite this, it has no symptoms in its early stages. Your blood pressure must be measured to know whether it is high.
The medical communitys knowledge of high blood pressure is great, but far from perfect. However, the biggest problem with treatment of high blood pressure is not a lack of knowledge, but a lack of the application of our current knowledge. Follow the advice below, and youll be able to gain control of an important part of your healthcare.
Take your own blood pressure
The pressure exerted on the arteries when the heart is beating is called the "systolic" blood pressure. This is the number at which sounds are first heard through the stethoscope.
The pressure present in the arteries when the heart is not pumping is termed the "diastolic" blood pressure. It is the pressure when sounds are last heard with the stethoscope.
The blood pressure is expressed as the systolic pressure "over" the diastolic pressure. Blood pressure increases as we age, but the number generally regarded as "normal" is 120/80.
What does High Blood Pressure do to the body?
High blood pressure affects the blood vessels, causing them to clog or become weak. It is therefore one of the important factors causing:
- Heart Attacks (from blockages in the heart arteries) HeartPoint: Coronary Artery Disease
- Strokes (blockages or weakening of vessels to the brain)
- Kidney Failure from injury to the kidney and its blood vessels. It is a major cause of kidney failure (renal failure) which may require dialysis
- Heart Failure is a frequent occurrence in long standing hypertension. The heart initially compensates for the increased work of pushing against the elevated pressure in the vessels by becoming thick (hypertrophied). The person with this thickening may not notice any problems even at this stage. Eventually the muscle can weaken, and heart failure can occur. HeartPoint: Congestive Heart Failure
What causes high blood pressure?
The majority of times, there is no clear cause which can be identified. In a few patients (approximately 2%), high blood pressure may be traced to other "secondary causes" (see next section).
The actual mechanisms which explain why the blood pressure is high has to do mainly with the constriction of the small arterioles which are in all of the tissues of the body. When these are even slightly smaller than normal, the overall effect is that of a marked decrease in the volume that blood can flow in. Imagine a hose: You put a narrow nozzle at the end the pressure really goes up in the hose, doesnt it!
High blood pressure is more common:
- In patients whose families have high blood pressure
- In those over 35 years old
- In males
- In Afro-Americans
- In women on oral contraceptives
High blood pressure has its roots in many cases simply with the genes we received from our parents. High blood pressure is far more common in families where other members have this condition. This does not mean that you must have a history of high blood pressure in your family to have it yourself. It is very interesting to note that while the incidence of high blood pressure is low in Japan, it is higher in Japanese who migrate to America, underscoring the idea that there are things that we do culturally that will affect the incidence of high blood pressure. These include:
- Being overweight
- Eating high sodium diet
- Exercising too little
- Drink more than two alcoholic drinks daily
There are many other factors which have been felt to be related to high blood pressure. While these are interesting topics of debate and scientific curiosity, they are not nearly as important as the factors listed above.
Secondary causes of high blood pressure
The "average" or "run of the mill" case of high blood pressure is caused by the genes that are inherited with very important contributions from lifestyle. This is "Primary" Hypertension, and is discussed in the section above. About 2% of the time, there are specific abnormalities which are an identifiable reason for high blood pressure in some people. Some of these causes include"
- A number of kidney diseases cause high blood pressure.
- Disorders of the adrenal glands. These organs live right above the kidneys, and are responsible for releasing many hormones which regulate blood pressure and other functions. They are composed of an inner and an outer layer. The inner layer produces substances such as "adrenaline" which we've all heard of. The outer layer produce various steroid hormones. Disorders include the next three items.
- "Pheochromocytoma", a long term for one of the rarest of all human tumors. Since high blood pressure is so common however, doctors think about it way more often then they ever find it. This tumor produces adrenaline and/or similar substances. Patients with this disorder typically have "paroxyms" or spells of high blood pressure which are accompanied by strong and rapid heart beats, sweating and headaches.
- Cushing's syndrome is caused from the overproduction of "glucocorticoids" -- steroids that participate in regulating the metabolism of glucose and other food substances. The site of this overproduction is in the adrenals, although they may be simply reacting to stimulation by other abnormal organs.
- Adrenal "adenomas" (non-malignant tumors) or "hyperplasia" (too much tissue growth) can be responsible for excess levels of "mineralcorticoids" -- steroids which participate in the regulation of sodium, potassium, and other minerals. Their effect is primarily from holding onto too much sodium.
- An obstruction to the arteries to the kidneys ("Renal Artery Stenosis"). In this situation, the kidney which is blocked doesn't "see" enough blood pressure, and releases chemicals causing the blood pressure to go up. In this way, that kidney may produce enough blood pressure to satisfy itself, while the rest of the body sees very high pressures as a result. This obstruction can come from atherosclerosis (blockage with cholesterol) or from a congenital disorder of the connective tissue in the blood vessels (Fibromuscular Dysplasia).
- A "Coarctation" (or narrowing) of the aorta can cause high blood pressure in a manner similar to Renal Artery Stenosis noted above. This is a congenital condition present from birth where narrowing occurs in the aorta, typically just beyond the point where the artery to the left arm is given off. Blood has to find a way around the obstruction so that there is enough flow for the abdomen, legs, etc. The body is usually successful at providing enough blood around the obstruction, but the pressure is low, including the pressure to the kidneys. They behave in exactly the same way they do in Renal Artery Stenosis, releasing chemicals to raise their own pressure. However, the pressure in the upper half of the body, particularly the heart and the brain, see very high pressures and can therefore have all of the complications of high blood pressure.
- Sleep Apnea, which is primarily known as a cause for loud nighttime snoring and daytime sleepiness, is pretty common, and has been associated with high blood pressure which improves with treatment of the apnea.
Again, it is worth remembering that these are all pretty uncommon conditions. Their presence may be suggested by an early age of onset of hypertension, or a sudden worsening, or difficulty in treatment. Still, most cases even in these categories will be due to "plain old primary" hypertension. Investigations to "rule out" these conditions may include a careful history, particularly for some of the kidney diseases. Various features of the physical examination, including bruits (particular noises heard with the stethoscope when blood rushes through narrowed arteries) in the case of Renal Artery Stenosis, or substantial differences in the blood pressure in the arms and legs (in the case of coarctation) can be helpful. Measuring certain chemicals in the blood or urine are important in the abnormal conditions of the adrenal gland. Specialized imaging techniques, such as ultrasound, nuclear medicine studies, CT scans or MRI's, or arteriograms may be needed to diagnose the disorders.
When and how is high blood pressure treated?
There is debate (when isn't there?) about the level of blood pressure which should be treated. As in so many areas, the debate often obscures the obvious - the higher the level of the blood pressure, the higher the risk of suffering one of its complications.
Likewise, there is tremendous debate about how patients should be treated. Again, don't overlook the obvious in this situation either. People with hypertension should be encouraged to:
- Maintain ideal body weight
- Reduce consumption of sodium
- Maintain at least a modest exercise program
Medications may also be required to maintain adequate control. As in any other area of medicine, when to start medications is a decision balancing the risks and benefits of therapy. In patients with high blood pressure, side effects and costs of medications are also factors which weigh heavily on which agent if any is prescribed. For the physician, it is a difficult area due to the fact that patients don't feel bad, yet must be prescribed medicines which can be costly and have side effects which make the patient feel worse than they did prior to treatment.
At what level is blood pressure too high?
First of all, several readings are required to diagnose High Blood Pressure. Blood pressure is generally felt to be abnormally high at a level of 140/90, and some sort of definitive therapy and follow-up should be started at this level. This may involve weight loss, a low salt diet, and a modest exercise program. It should definitely lead to follow-up appointments, and if the pressures remain high, therapy with medications.
My blood pressure is so high, I'm going to have a stroke!
This is really far less common than is feared. In the "old days" before we had so many different and effective medications for high blood pressure, a person's pressure could go very high and stay there . . . or go even higher. Nowadays, it is very uncommon for this to occur. Remember, when people exercise, their blood pressure typically goes up to the 160-210 mmHg range -- your arteries were meant to take this level. Certainly, levels this high all the time can lead to very substantial problems, but these are generally long-range problems, not something that's going to happen right now.
Cant you tell when your blood pressure is high?
I would say definitely not. It is not called the "silent killer" for nothing. I have met patients who have really felt they can tell when their pressure is high, and indeed when they have a headache or blurry vision it may be quite high. However, I have yet to meet anyone who is anywhere near as accurate as a blood pressure cuff! There are two dangers to believing you can tell your blood pressure, and I have seen many cases of both:
- You think you can tell your what your blood pressure is, you believe its okay and don't get it checked, but your blood pressure is actually high . . . You become another person with untreated high blood pressure and its complications.
- You have a headache, or blurry vision, or some other symptom and feel "its just because my blood pressure is up". You then self-administer medicines to lower your pressure. You can then get your pressure to where it's actually too low. Alternatively, you may be overlooking a symptom which is being caused by another disease.
The only way to know whether you have high blood pressure is to have it taken by a person who knows how (those automatic machines you sit at in the supermarket are not necessarily kept accurate condition!). Even if youve previously had normal pressure, you should have it taken at least once a year.
My prescription ran out. Does that mean my blood pressure is cured?
Again, definitely not. Unfortunately, most patients will need to take some sort of medication for the rest of their lives. Fortunately, this will do them a great deal of good. But the medicines dont "cure" the high blood pressure like antibiotics cure an infection. You have to take the medications continuously for them to work. Call your doctors office and get refills!
Will I ever be able to get off of these medications?
In general, patients will need to continue their medications indefinitely. Changes in lifestyle already mentioned may be successful in helping you get off your medications with your doctors guidance. My practice has been to treat sustained high blood pressure once it has been documented appropriately, and then back it off if the patient is following those lifestyle changes and the pressure is under good control. The desire to get off meds gives them motivation to lose weight, etc.
Should I get a blood pressure cuff? Which one?
I personally feel that patients with hypertension should have a blood pressure cuff at home. I have found the "finger cuffs" pretty unreliable in general, although some are accurate. Some are easier than others to use by yourself, a less important feature if you have a friend or mate who will do it for you. Regardless of the type of cuff, bring it to your physicians office so that they can check for its accuracy when you first buy it, and then every year or two (or after it takes a fall).
Why does my blood pressure vary so much?
Many people seem to feel that blood pressure is a constant, like the color of their hair. However, like our pulse rate, blood pressure is designed to vary depending on the circumstances. If a person has a widely varying blood pressures, it is referred to as "labile". The blood pressure to consider in treatment is often somewhere around the average of the readings taken. If a persons systolic blood pressure is ranging from 100-130 mm mercury, generally no treatment is necessary.
But I cant have high blood pressure! My blood pressure has always been normal!
This is one of my secret favorites. It is not as amazing when you consider the fact that every case of high blood pressure has to start somewhere!
Exactly when should I take my medication? What should I do if I forget a dose?
This will vary from one medication to another, and from one patient to another. Ask your doctor or pharmacist.
What is "White Coat Syndrome"?
"White coat syndrome" is a situation where patients have high blood pressure in the doctors office but nowhere else. The situation is generally not this clear-cut, however, and often the patient has occasional episodes where the blood pressure is high when taken at home, but it is reliably high when taken in the physicians office. Some patients with sustained high blood pressure will have higher readings in the doctors office than at home. It is really not very uncommon. The patient generally does not feel the slightest bit of apprehension when coming to the doctor, or even in the office when the blood pressure is high. The mechanism appears to occur at a subconscious level.
If blood pressure is just very occasionally high, it is not as dangerous as when it remains elevated most of the time. If in fact the blood pressure is noted to be high almost exclusively in the doctors office, many physicians will not prescribe any treatment at all. Some studies have suggested however that white coat hypertension may "turn into" sustained high blood pressure. This really makes more sense to me since the same types of stresses occur in everyday life.
There are two main problems or dangers with this condition:
- The first is the tendency for some patients to put themselves in this category, saying to themselves "its only high at the doctors office . . . I dont need any treatment".
- The other danger is that the high reading taken in the doctors office is assumed to be the patients usual blood pressure, and he or she is overtreated.
The most prudent course seems to be:
- Monitor patients with white coat syndrome closely. Obtain a blood pressure cuff and have your blood pressure taken on multiple occasions. Write the readings down and bring them to your physician.
- There are devices which can be worn for 24 hours to measure the blood pressure throughout the day. These may be useful in providing a clearer picture of how long and under what circumstances a persons blood pressure may be elevated.
- Continue to follow the general rules noted above: strive to maintain ideal body weight, avoid overuse of salt and sodium, and follow an exercise program.
Are there any medications I should avoid?
"Over-the-counter" medications that include decongestants can drive your blood pressure up. These are used in cold/sinus/cough preparations. Pure "antihistamines" without are generally safe, as are several prescription preparations. Tell your pharmacist that you have high blood pressure, and ask which preparations to take, and which to avoid.
REMEMBER THESE KEY POINTS
- The biggest problem with treatment of high blood pressure is not a lack of knowledge about it, but a lack of the application of our current knowledge.
- Take your medications as prescribed.
- Choose food low in salt. Don't add salt at the table. Learn to use other types of seasonings.
- Maintain ideal body weight.
- Pursue a modest exercise program.
- Get your medications filled before they run out.
- Follow-up with your doctor.
©COPY;1997 HeartPoint Updated July 1997
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