Hypertension

Hypertension

Submitted by: Patrick D. delos Santos

Batch 6

Submitted to: Mr. Jonathan Cuevas

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What is high blood pressure? High blood pressure (HBP) or hypertension means high pressure (tension) in the arteries. Arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension", and a blood pressure of 140/90 or above is considered high. The top number, the systolic blood pressure, corresponds to the pressure in the arteries as the heart contracts and pumps blood forward into the arteries. The bottom number, the diastolic pressure, represents the pressure in the arteries as the heart relaxes after the contraction. The diastolic pressure reflects the lowest pressure to which the arteries are exposed. An elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease, kidney (renal) disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke (brain damage). These complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. For that reason, the diagnosis of high blood pressure is important so efforts can be made to normalize blood pressure and prevent complications. It was previously thought that rises in diastolic blood pressure were a more important risk factor than systolic elevations, but it is now known that in people 50 years or older systolic hypertension represents a greater risk.

How is the blood pressure measured? The blood pressure usually is measured with a small, portable instrument called a blood pressure cuff (sphygmomanometer). (Sphygmo is Greek for pulse, and a manometer measures pressure.) The blood pressure cuff consists of an air pump, a pressure gauge, and a rubber cuff. The instrument measures the blood pressure in units called millimeters of mercury (mm Hg). The cuff is placed around the upper arm and inflated with an air pump to a pressure that blocks the flow of blood in the main artery (brachial artery) that travels through the arm. The arm is then extended at the side of the body at the level of the heart, and the pressure of the cuff on the arm and artery is gradually released. As the pressure in the cuff decreases, a health practitioner listens with a stethoscope over the artery at the front of the elbow. The pressure at which the practitioner first hears a pulsation from the artery is the systolic pressure (the top number). As the cuff pressure decreases further, the pressure at which the pulsation finally stops is the diastolic pressure (the bottom number).

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How is high blood pressure defined? blood pressure can be affected by several factors, so it is important to standardize the environment when blood pressure is measured. For at least one hour before blood pressure is taken, avoid eating, strenuous exercise (which can lower blood pressure), smoking, and caffeine intake. Other stresses may alter the blood pressure and need to be considered when blood pressure is measured.

Even though most insurance companies consider high blood pressure to be 140/90 and higher for the general population, these levels may not be appropriate cut-offs for all individuals. Many experts in the field of hypertension view blood pressure levels as a range, from lower levels to higher levels. Such a range implies there are no clear or precise cut-off values to separate normal blood pressure from high blood pressure. Individuals with so-called pre-hypertension (defined as a blood pressure between 120/80 and 139/89) may benefit from lowering of blood pressure by life style modification and possibly medication especially if there are other risk factors for end-organ damage such as diabetes or kidney disease (life style changes are discussed below). For some people, blood pressure readings lower than 140/90 may be a more appropriate normal cut-off level. For example, in certain situations, such as in patients with long duration (chronic) kidney diseases that spill (lose) protein into the urine (proteinuria), the blood pressure is ideally kept at 130/80, or even lower. The purpose of reducing the blood pressure to this level in these patients is to slow the progression of kidney damage. Patients with diabetes (diabetes mellitus) may also benefit from blood pressure that is maintained at a level lower than 130/80. In addition, African Americans, who have an increased risk for developing the complications of hypertension, may decrease this risk by reducing their systolic blood pressure to less than 135 and the diastolic blood pressure to 80 mm Hg or less. In line with the thinking that the risk of end-organ damage from high blood pressure represents a continuum, statistical analysis reveals that beginning at a blood pressure of 115/75 the risk of cardiovascular disease doubles with each increase in blood pressure of 20/10. This type of analysis has led to an ongoing "rethinking" in regard to who should be treated for hypertension, and what the goals of treatment should be. Isolated systolic high blood pressure Remember that the systolic blood pressure is the top number in the blood pressure reading and represents the pressure in the arteries as the heart contracts and pumps blood into the arteries. A systolic blood pressure that is persistently higher than 140 mm Hg is usually considered elevated, especially when associated with an elevated diastolic pressure (over 90). Isolated systolic hypertension, however, is defined as a systolic pressure that is above 140 mm Hg with a diastolic pressure that still is below 90. This disorder primarily affects older people and is characterized by an increased (wide) pulse pressure. The pulse pressure is the difference between the systolic and diastolic

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blood pressures. An elevation of the systolic pressure without an elevation of the diastolic pressure, as in isolated systolic hypertension, therefore, increases the pulse pressure. Stiffening of the arteries contributes to this widening of the pulse pressure. Once considered to be harmless, a high pulse pressure is now considered an important precursor or indicator of health problems and potential end-organ damage. Isolated systolic hypertension is associated with a two to four times increased future risk of an enlarged heart, a heart attack (myocardial infarction), a stroke (brain damage), and death from heart disease or a stroke. Clinical studies in patients with isolated systolic hypertension have indicated that a reduction in systolic blood pressure by at least 20 mm to a level below 160 mm Hg reduces these increased risks. White coat high blood pressure A single elevated blood pressure reading in the doctor's office can be misleading because the elevation may be only temporary. It may be caused by a patient's anxiety related to the stress of the examination and fear that something will be wrong with his or her health. The initial visit to the physician's office is often the cause of an artificially high blood pressure that may disappear with repeated testing after rest and with follow-up visits and blood pressure checks. One out of four people that are thought to have mild hypertension actually may have normal blood pressure when they are outside the physician's office. An increase in blood pressure noted only in the doctor's office is called 'white coat hypertension.' The name suggests that the physician's white coat induces the patient's anxiety and a brief increase in blood pressure. A diagnosis of white coat hypertension might imply that it is not a clinically important or dangerous finding. However, caution is warranted in assessing white coat hypertension. An elevated blood pressure brought on by the stress and anxiety of a visit to the doctor may not necessarily always be a harmless finding since other stresses in a patient's life may also cause elevations in the blood pressure that are not ordinarily being measured. Monitoring blood pressure at home by blood pressure cuff or continuous monitoring equipment or at a pharmacy can help estimate the frequency and consistency of higher blood pressure readings. Additionally, conducting appropriate tests to search for any complications of hypertension can help evaluate the significance of variable blood pressure readings.

Borderline high blood pressure Borderline hypertension is defined as mildly elevated blood pressure higher than 140/90 mm Hg at some times, and lower than that at other times. As in the case of white coat hypertension, patients with borderline hypertension need to have their blood pressure taken on several occasions and their end-organ damage assessed in order to establish whether their hypertension is significant. People with borderline hypertension may have a tendency as they get older to develop more sustained or higher elevations of blood pressure. They have a modestly increased risk of developing heart-related (cardiovascular) disease. Therefore, even if the hypertension does not appear to be significant initially, people

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with borderline hypertension should have continuing follow-up of their blood pressure and monitoring for the complications of hypertension. If, during the follow-up of a patient with borderline hypertension, the blood pressure becomes persistently higher than 140/ 90 mm Hg, an anti-hypertensive medication is usually started. Even if the diastolic pressure remains at a borderline level (usually under 90 mm Hg, yet persistently above 85) treatment may be started in certain circumstances. Causes Blood pressure measurements are the result of the force of the blood produced by the heart and the size and condition of the arteries. Many factors can affect blood pressure, including: • • •

How much water and salt you have in your body The condition of your kidneys, nervous system, or blood vessels The levels of different body hormones

High blood pressure can affect all types of people. You have a higher risk of high blood pressure if you have a family history of the disease. High blood pressure is more common in African Americans than Caucasians. Smoking, obesity, and diabetes are all risk factors for hypertension. Most of the time, no cause is identified. This is called essential hypertension. High blood pressure that results from a specific condition, habit, or medication is called secondary hypertension. Too much salt in your diet can lead to high blood pressure. Secondary hypertension may also be due to: • • • • • • • • • •

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Adrenal gland tumor Alcohol abuse Anxiety and stress Arteriosclerosis Birth control pills Coarctation of the aorta Cocaine use Cushing syndrome Diabetes Kidney disease, including: o Glomerulonephritis (inflammation of kidneys) o Kidney failure o Renal artery stenosis o Renal vascular obstruction or narrowing Medications o Appetite suppressants o Certain cold medications o Corticosteroids o Migraine medications Hemolytic-uremic syndrome

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• • • • • • • • • •

Henoch-Schonlein purpura Obesity Pain Periarteritis nodosa Pheochromocytoma Pregnancy (called gestational hypertension) Primary hyperaldosteronism Renal artery stenosis Retroperitoneal fibrosis Wilms' tumor

What are the causes of secondary high blood pressure? As mentioned previously, 5% of people with hypertension have what is called secondary hypertension. This means that the hypertension in these individuals is secondary to (caused by) a specific disorder of a particular organ or blood vessel, such as the kidney, adrenal gland, or aortic artery. Renal (kidney) hypertension Diseases of the kidneys can cause secondary hypertension. This type of secondary hypertension is called renal hypertension because it is caused by a problem in the kidneys. One important cause of renal hypertension is narrowing (stenosis) of the artery that supplies blood to the kidneys (renal artery). In younger individuals, usually women, the narrowing is caused by a thickening of the muscular wall of the arteries going to the kidney (fibromuscular hyperplasia). In older individuals, the narrowing generally is due to hard, fat-containing (atherosclerotic) plaques that are blocking the renal artery. How does narrowing of the renal artery cause hypertension? First, the narrowed renal artery impairs the circulation of blood to the affected kidney. This deprivation of blood then stimulates the kidney to produce the hormones, renin and angiotensin. These hormones, along with aldosterone from the adrenal gland, cause a constriction and increased stiffness (resistance) in the peripheral arteries throughout the body, which results in high blood pressure. Renal hypertension is usually first suspected when high blood pressure is found in a young individual or a new onset of high blood pressure is discovered in an older person. Screening for renal artery narrowing then may include renal isotope (radioactive) imaging, ultrasonographic (sound wave) imaging, or magnetic resonance imaging (MRI) of the renal arteries. The purpose of these tests is to determine whether there is a restricted blood flow to the kidney and whether angioplasty (removal of the restriction in the renal arteries) is likely to be beneficial. However, if the ultrasonic assessment indicates a high resistive index within the kidney (high resistance to blood flow), angioplasty may not improve the blood pressure because chronic damage in the kidney from long-standing hypertension already exists. If any of these tests are abnormal or the doctor's suspicion of renal artery narrowing is high enough, renal angiography (an x-ray study in which dye is injected into the renal artery) is done. Angiography is the ultimate test to actually visualize the narrowed renal artery.

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A narrowing of the renal artery may be treated by balloon angioplasty. In this procedure, the physician threads a long narrow tube (catheter) into the renal artery. Once the catheter is there, the renal artery is widened by inflating a balloon at the end of the catheter and placing a permanent stent (a device that stretches the narrowing) in the artery at the site of the narrowing. This procedure usually results in an improved blood flow to the kidneys and lower blood pressure. Moreover, the procedure also preserves the function of the kidney that was partially deprived of its normal blood supply. Only rarely is surgery needed these days to open up the narrowing of the renal artery. Any of the other types of chronic kidney disease that reduces the function of the kidneys can also cause hypertension due to hormonal disturbances and/or retention of salt. It is important to remember that not only can kidney disease cause hypertension, but hypertension can also cause kidney disease. Therefore, all patients with high blood pressure should be evaluated for the presence of kidney disease so they can be treated appropriately. Adrenal gland tumors Two rare types of tumors of the adrenal glands are less common, secondary causes of hypertension. The adrenal glands sit right on top of the kidneys. Both of these tumors produce excessive amounts of adrenal hormones that cause high blood pressure. These tumors can be diagnosed from blood tests, urine tests, and imaging studies of the adrenal glands. Surgery is often required to remove these tumors or the adrenal gland (adrenalectomy), which usually relieves the hypertension. One of the types of adrenal tumors causes a condition that is called primary hyperaldosteronism because the tumor produces excessive amounts of the hormone aldosterone. In addition to the hypertension, this condition causes the loss of excessive amounts of potassium from the body into the urine, which results in a low level of potassium in the blood. Hyperaldosteronism is generally first suspected in a person with hypertension when low potassium is also found in the blood. (Also, certain rare genetic disorders affecting the hormones of the adrenal gland can cause secondary hypertension.) The other type of adrenal tumor that can cause secondary hypertension is called a pheochromocytoma. This tumor produces excessive catecholamines, which include several adrenaline-related hormones. The diagnosis of a pheochromocytoma is suspected in individuals who have sudden and recurrent episodes of hypertension that are associated with flushing of the skin, rapid heart beating (palpitations), and sweating, in addition to the symptoms associated with high blood pressure. Coarctation of the aorta Coarctation of the aorta is a rare hereditary disorder that is one of the most common causes of hypertension in children. This condition is characterized by a narrowing of a segment of the aorta, the main large artery coming from the heart. The aorta delivers blood to the arteries that supply all of the body's organs, including the kidneys.

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The narrowed segment (coarctation) of the aorta generally occurs above the renal arteries, which causes a reduced blood flow to the kidneys. This lack of blood to the kidneys prompts the renin-angiotensin-aldosterone hormonal system to elevate the blood pressure. Treatment of the coarctation is usually the surgical correction of the narrowed segment of the aorta. Sometimes, balloon angioplasty (as described above for renal artery stenosis) can be used to widen (dilate) the coarctation of the aorta. The metabolic syndrome and obesity Genetic factors play a role in the constellation of findings that make up the "metabolic syndrome." Individuals with the metabolic syndrome have insulin resistance and a tendency to have type 2 diabetes mellitus (non-insulin-dependent diabetes). Obesity, especially associated with a marked increase in abdominal girth, leads to high blood sugar (hyperglycemia), elevated blood lipids (fats), vascular inflammation, endothelial dysfunction (abnormal reactivity of the blood vessels), and hypertension all leading to premature atherosclerotic vascular disease. The American Obesity Association states the risk of developing hypertension is five to six times greater in obese Americans, age 20 to 45, compared to non-obese individuals of the same age. The American Journal of Clinical Nutrition reported in 2005 that waist size was a better predictor of a person's blood pressure than body mass index (BMI). Men should strive for a waist size of 35 inches or under and women 33 inches or under. The epidemic of obesity in the United States contributes to hypertension in children, adolescents, and adults. What are the symptoms of high blood pressure? Uncomplicated high blood pressure usually occurs without any symptoms (silently) and so hypertension has been labeled "the silent killer." It is called this because the disease can progress to finally develop any one or more of the several potentially fatal complications of hypertension such as heart attacks or strokes. Uncomplicated hypertension may be present and remain unnoticed for many years, or even decades. This happens when there are no symptoms, and those affected fail to undergo periodic blood pressure screening. Some people with uncomplicated hypertension, however, may experience symptoms such as headache, dizziness, shortness of breath, and blurred vision. The presence of symptoms can be a good thing in that they can prompt people to consult a doctor for treatment and make them more compliant in taking their medications. Often, however, a person's first contact with a physician may be after significant damage to the end-organs has occurred. In many cases, a person visits or is brought to the doctor or an emergency room with a heart attack, stroke, kidney failure, or impaired vision (due to damage to the back part of the retina). Greater public awareness and frequent blood pressure screening may help to identify patients with undiagnosed high blood pressure before significant complications have developed. About one out of every 100 (1%) people with hypertension is diagnosed with severe high blood pressure (accelerated or malignant hypertension) at their first visit to the doctor. In these patients, the diastolic blood pressure (the minimum pressure) exceeds 140 mm Hg! Affected persons often experience severe headache, nausea, visual symptoms, dizziness, and sometimes kidney failure. Malignant hypertension is

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a medical emergency and requires urgent treatment to prevent a stroke (brain damage). Exams and Tests Your health care provider will perform a physical exam and check your blood pressure. If the measurement is high, your doctor may think you have high blood pressure. The measurements need to be repeated over time, so that the diagnosis can be confirmed. If you monitor your blood pressure at home, you may be asked the following questions: • • • •

What was your most recent blood pressure reading? What was the previous blood pressure reading? What is the average systolic (top number) and diastolic (bottom number) reading? Has your blood pressure increased recently?

Other tests may be done to look for blood in the urine or heart failure. Your doctor will look for signs of complications to your heart, kidneys, eyes, and other organs in your body. These tests may include: • • • •

Chem-20 Echocardiogram Urinalysis Ultrasound of the kidneys

Treatment the goal of treatment is to reduce blood pressure so that you have a lower risk of complications. There are many different medicines that can be used to treat high blood pressure, including: • • • • • • • • •

Alpha blockers Angiotensin-converting enzyme (ACE) inhibitors Angiotensin receptor blockers (ARBs) Beta-blockers Calcium channel blockers Central alpha agonists Diuretics Renin inhibitors, including aliskiren (Tekturna) Vasodilators

Your doctor may also tell you to exercise, lose weight, and follow a healthier diet. If you have pre-hypertension, your doctor will recommend the same lifestyle changes to bring your blood pressure down to a normal range.

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Often, a single blood pressure drug may not be enough to control your blood pressure, and you may need to take two or more drugs. It is very important that you take the medications prescribed to you. If you have side effects, your health care provider can substitute a different medication. Possible Complications • • • • • • • • • •

Aortic dissection Blood vessel damage (arteriosclerosis) Brain damage Congestive heart failure Kidney damage Kidney failure Heart attack Hypertensive heart disease Stroke Vision loss

Prevention Adults over 18 should have their blood pressure checked routinely. Lifestyle changes may help control your blood pressure: • • • • • • •

Lose weight if you are overweight. Excess weight adds to strain on the heart. In some cases, weight loss may be the only treatment needed. Exercise regularly. If possible, exercise for 30 minutes on most days. Eat a diet rich in fruits, vegetables, and low-fat dairy products while reducing total and saturated fat intake (the DASH diet is one way of achieving this kind of dietary plan). (See: Heart disease and diet) Avoid smoking. (See: Nicotine withdrawal) If you have diabetes, keep your blood sugar under control. Do not consume more than 1 or 2 alcoholic drinks per day. Try to manage your stress.

Follow your health care provider's recommendations to modify, treat, or control possible causes of secondary hypertension.

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