Hypertension

What is hypertension?

Persistent rise of blood pressure is known as hypertension. High blood pressure is a trait as opposed to a specific disease & represents a quantitative rather than a qualitative deviation from the norm. Any definition of hypertension is therefore arbitrary.

Categories for Blood Pressure Levels in Adults (in mmHg, or millimeters of mercury)

Category	Systolic (top number)		Diastolic (bottom number)
Normal	Less than 120	And	Less than 80
Prehypertension	120–139	Or	80–89
High blood pressure
Stage 1	140–159	Or	90–99
Stage 2	160 or higher	Or	100 or higher

High Blood Pressure Causes :

In about 10% of people, high blood pressure is caused by another disease (this is called secondary hypertension). In such cases, when the root cause is treated, blood pressure usually returns to normal. These causes of secondary hypertension include the following conditions:

• Chronic kidney disease
  
  
• Tumors or other diseases of the adrenal gland
  
  
• Coarctation of the aorta - A narrowing of the aorta that you are born with that can cause high blood pressure in your arms
  
  
• Pregnancy
  
  
• Use of birth control pills
  
  
• Alcohol addiction
  
  
• Thyroid dysfunction

In the other 90% of cases, the cause of high blood pressure is not known (referred to as primary hypertension). Although the specific cause is unknown, certain factors are recognized as contributing to high blood pressure.

Factors that can't be changed

• Age
  
  
• Race
  
  
• Socioeconomic status
  
  
• Family history (heredity)
  
  
• Gender

Factors that can be changed

• Overweight (obesity)
  
  
• Sodium (salt) sensitivity:
  
  
• Alcohol use
  
  
• Birth control pills (oral contraceptive use)
  
  
• Lack of exercise (physical inactivity)
  
  
• Drugs

High Blood Pressure Symptoms :

High blood pressure usually causes no symptoms.

• Even if high blood pressure does cause symptoms, the symptoms are usually mild and nonspecific (vague, or suggesting many different disorders).
  
  
• Thus, high blood pressure often is labeled "the silent killer."
  
  
• People who have high blood pressure typically don't know it until their blood pressure is measured.

Sometimes people with high blood pressure have the following symptoms:

• Headache
  
  
• Dizziness
  
  
• Blurred vision
  
  
• Nausea

People often do not seek medical care until they have symptoms arising from the organdamage caused by chronic (ongoing, long-term) high blood pressure. The following types of organ damage are commonly seen in chronic high blood pressure:

• Heart attack
  
  
• Heart failure
  
  
• Stroke or "mini stroke" (transient ischemic attack, TIA)
  
  
• Kidney failure
  
  
• Eye damage with loss of vision
  
  
• Peripheral arterial disease
  
  
• Outpouchings of the aorta, called aneurysms

About 1% of people with high blood pressure do not seek medical care until the high blood pressure is very severe, a condition known as malignant hypertension.

• In malignant hypertension, the diastolic blood pressure (the lower number) often exceeds 140 mm Hg.
  
  
• Malignant hypertension may be associated with headache, light-headedness, or nausea.
  
  
• This degree of high blood pressure requires emergency hospitalization and lowering of blood pressure to prevent brain hemorrhage or stroke.

It is of utmost importance to realize that high blood pressure can be unrecognized for years, causing no symptoms but causing progressive damage to the heart, other organs, and blood vessels.

Exams and Tests :

The only way to tell whether you have high blood pressure is to have it measured with a blood pressure cuff (sphygmomanometer).

• This device consists of a gauge and a rubber cuff that is placed around your arm and inflated.
  
  
• Having your blood pressure measured is painless and takes just a few minutes.

Tests will be ordered to check for causes of high blood pressure and to assess any organ damage from high blood pressure or its treatment. These tests may include the following:

• Blood tests including measurement ofelectrolytes, blood urea, and creatininelevels (to assess potential kidney damage)
  
  
• Lipid profile for levels of various kinds of cholesterol
  
  
• Special tests for hormones of the adrenal gland or thyroid gland
  
  
• Urine tests for electrolytes and hormones

A noninvasive, painless eye examination with an ophthalmoscope will look forocular damage.

Ultrasound of the kidneys, CT scan of the abdomen, or both may be done to assess damage or enlargement of the kidneys and adrenal glands.

Any of the following may be performed to detect damage to the heart or blood vessels:

• Electrocardiogram(ECG) is a noninvasive test that detects the electrical activity of the heart and records it on paper. ECG is helpful for quantitating any damage of the heart muscle, such as heart attack, and/or thickening/hypertrophy of the heart wall/muscle, common complications of high blood pressure.
  
  
• Echocardiogram is an ultrasound examination of the heart taken through the chest. Sound waves take a picture of the heart as it beats and relaxes and then transmits these images to a video monitor. The echo can detect problems with the heart such as enlargement, abnormalities in motion of the heart wall, blood clots, and heart valve abnormalities. It also gives a good measurement of the strength of the heart muscle (ejection fraction). The echocardiogram is more accurate than an ECG, but also more expensive.
  
  
• A plain chest x-ray primarily provides an estimate of the size of the heart, but it is much less specific than echocardiography, which looks inside the heart.
  
  
  
• Doppler ultrasound is used to check blood flow through arteries at pulse points in your arms, legs, hands, and feet. This is an accurate way to detectperipheral vascular disease, which can be associated with high blood pressure. It also can depict the arteries to both kidneys and sometimes depicts narrowings that can lead to high BP in a minority of patients.

Medications :

Medications most often prescribed for high blood pressure include the following:

Water pills (diuretics)

• Diuretics are used very widely to control mildly high blood pressure, and are often used in combination with other medications.
  
  
• They increase sodium excretion and urine output and decrease blood volume. The sensitivity to the effect of other hormones in your body is decreased.
  
  
• Example - Hydrochlorothiazide(HydroDIURIL)

Beta-blockers

• Beta-blockers reduce heart rate and decrease the force of heart contraction, thereby reducing the pressure generated by the heart.
  
  
• They are preferred for people who have associated coronary heart disease, angina, or history of a heart attack, since they also prevent recurrent heart attacks and sudden death.
  
  
• Examples - Carvedilol (Coreg), metoprolol(Lopressor), atenolol (Tenormin)
  
  
• Side effects - Fatigue, depression,impotence, nightmares

Calcium channel blockers

• Calcium channel blocking agents work by relaxing the muscle in the walls of the arteries.
  
  
• They also reduce the force of contraction of the heart.
  
  
• Examples - Nifedipine (Procardia), diltiazem (Cardizem), verapamil (Isoptin, Calan), nicardipine (Cardene), amlodipine (Norvasc), felodipine (Plendil)
  
  
• Side effects - Ankle swelling, fatigue, headache, constipation, flushing

Angiotensin-converting enzyme (ACE) inhibitors

• ACE inhibitors stop the production of a chemical called angiotensin II, a very potent chemical that causes blood vessels to contract, a cause of high blood pressure. Blockage of this chemical causes the blood vessels to relax.
  
• Examples - Captopril (Capoten), enalapril (Vasotec), lisinopril (Zestril, Prinivil),quinapril (Accupril), fosinopril (Monopril)
  
  
• Side effects are infrequent but sometimes they can worsen kidney function and raise blood potassium levels, especially in patients with damaged kidneys. ACE inhibitors sometimes cause dry cough and rarely angioedema(severe swelling around the trachea/windpipe).

Angiotensin receptor blockers or ARBs

• ARBs work on receptors in tissues all over the body to prevent uptake of angiotensin II, and therefore inhibit the vasoconstrictor effect of angiotensin II.
  
  
• Examples - Losartan (Cozaar), valsartan (Diovan), candesartan (Atacand), andirbesartan (Avapro)
  
  
• Side effects tend to be less with ARBs than ACEIs with much less cough.

Alpha-blockers

• Alpha-blockers relax blood vessels by blocking messages from the nervous system that cause muscular contraction.
  
  
• Examples - Terazosin (Hytrin), doxazosin (Cardura)
  
  
• Since publication of a study known as the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) in 42,000 patients, and premature termination of the alpha-blocker arm (discontinuation of treatment in the group receiving alpha-blockers) because of excessive incidence of congestive heart failure, alpha-blockers are no longer frequently prescribed and are primarily used in men with associated prostatism (benign prostatic hyperplasia, or enlargement of the prostate) symptoms.

Blockers of central sympathetic (autonomic nervous) system

• These agents block messages out of the brain from the autonomic nervous system that contract blood vessels. The autonomic nervous system is the part of the nervous system that is automatic and controls heart rate, breathingrate, and other basic functions.
  
  
• The effect of these drugs is to relax blood vessels, thus lowering blood pressure. These agents are not as popular because of excessive side effects, and no randomized trials demonstrate their effectiveness in lowering heart attacks, strokes, etc.
  
  
• Example - Clonidine (Catapres)

Direct vasodilators

• Direct vasodilators relax (dilate) the blood vessels to allow blood to flow under lower pressure.
  
  
• These medications are often given through an IV line in an emergency (that is, in malignant hypertension).
  
  
• Examples - Nitroprusside (Nitropress), diazoxide (Hyperstat). Oral medications are hydralazine and minoxidil.

Prevention :

The following strategies may help to prevent high blood pressure and organ damage it may cause. For more details on how you can achieve these goals, see Self-Care at Home.

• Eat a nutritious, low-fat diet.
  
  
• Exercise regularly.
  
  
• Decrease salt (sodium) intake: Read food labels so you know the salt content before you buy a product in the grocery store.
  
  
• Maintain a healthy weight: If you are overweight or obese, try to lose weight.
  
  
• Use alcohol in moderation, if at all.
  
  
• Stop smoking.
  
  
• Get your blood pressure checked periodically. Consider getting an accurate and easy-to-use home monitor.
  
  
• Take your blood pressure medications as directed, even if you're feeling fine.
  
  
• Reduce stress and practice relaxation: Physical activity will help with this.

High Blood Pressure (Hypertension) At A Glance :

• High blood pressure (hypertension) is designated as either essential (primary) hypertension or secondary hypertension and is defined as a consistently elevated blood pressure exceeding 140/90 mm Hg.
  
  
• In essential hypertension (95% of people with hypertension), no specific cause is found, while secondary hypertension (5% of people with hypertension) is caused by an abnormality somewhere in the body, such as in the kidney, adrenal gland, or aortic artery.
  
  
• Essential hypertension may run in some families and occurs more often in the African American population, although the genes for essential hypertension have not yet been identified.
  
  
• High salt intake, obesity, lack of regular exercise, excessive alcohol or coffee intake, and smoking may all adversely affect the outlook for the health of an individual with hypertension.
  
  
• High blood pressure is called "the silent killer" because it often causes no symptoms for many years, even decades, until it finally damages certain critical organs.
  
  
• Poorly controlled hypertension ultimately can cause damage to blood vessels in the eye, thickening of the heart muscle and heart attacks, hardening of the arteries (arteriosclerosis), kidney failure, and strokes.
  
  
• Heightened public awareness and screening of the population are necessary to detect hypertension early enough so it can be treated before critical organs are damaged.
  
  
• Lifestyle adjustments in diet and exercise and compliance with medication regimes are important factors in determining the outcome for people with hypertension.
  
  
• Several classes of anti-hypertensive medications are available, including ACE inhibitors, ARB drugs, beta-blockers, diuretics, calcium channel blockers, alpha-blockers, and peripheral vasodilators.
  
  
• Most anti-hypertensive medications can be used alone or in combination: some are used only in combination; some are preferred over others in certain specific medical situations; and some are not to be used (contraindicated) in other situations.
  
  
• The goal of therapy for hypertension is to bring the blood pressure down to 140/85 in the general population and to even lower levels in diabetics, African Americans, and people with certain chronic kidney diseases.
  
  
• Screening, diagnosing, treating, and controlling hypertension early in its course can significantly reduce the risk of developing strokes, heart attacks, or kidney failure.