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Hypertension : causes,s/s , treatment......

     Hypertension




Definition

Hypertension is high blood pressure. Blood pressure is the force of blood pushing against the walls of arteries as it flows through them. Arteries are the blood vessels that carry oxygenated blood from the heart to the body's tissues.

Description

As blood flows through arteries it pushes against the inside of the artery walls. The more pressure the blood exerts on the artery walls, the higher the blood pressure will be. The size of small arteries also affects the blood pressure. When the muscular walls of arteries are relaxed, or dilated, the pressure of the blood flowing through them is lower than when the artery walls narrow, or constrict
Blood pressure is highest when the heart beats to push blood out into the arteries. When the heart relaxes to fill with blood again, the pressure is at its lowest point. Blood pressure when the heart beats is called systolic pressure. Blood pressure when the heart is at rest is called diastolic pressure. When blood pressure is measured, the systolic pressure is stated first and the diastolic pressure second. Blood pressure is measured in millimeters of mercury (mm Hg). For example, if a person's systolic pressure is 120 and diastolic pressure is 80, it is written as 120/80 mm Hg. The American Heart Association has long considred blood pressure less than 140 over 90 normal for adults. However, the National Heart, Lung, and Blood Institute in Bethesda, Maryland released new clinical guidelines for blood pressure in 2003, lowering the standard normal readings. A normal reading was lowered to less than 120 over less than 80.
Hypertension is a major health problem, especially because it has no symptoms. Many people have hypertension without knowing it. In the United States, about 50 million people age six and older have high blood pressure. Hypertension is more common in men than women and in people over the age of 65 than in younger persons. More than half of all Americans over the age of 65 have hypertension. It also is more common in African-Americans than in white Americans.
Hypertension is serious because people with the condition have a higher risk for heart disease and other medical problems than people with normal blood pressure. Serious complications can be avoided by getting regular blood pressure checks and treating hypertension as soon as it is diagnosed.
If left untreated, hypertension can lead to the following medical conditions:
Arteriosclerosis is hardening of the arteries. The walls of arteries have a layer of muscle and elastic tissue that makes them flexible and able to dilate and constrict as blood flows through them. High blood pressure can make the artery walls thicken and harden. When artery walls thicken, the inside of the blood vessel narrows. Cholesterol and fats are more likely to build up on the walls of damaged arteries, making them even narrower. Blood clots also can get trapped in narrowed arteries, blocking the flow of blood.
Arteries narrowed by arteriosclerosis may not deliver enough blood to organs and other tissues. Reduced or blocked blood flow to the heart can cause a heart attack. If an artery to the brain is blocked, a stroke can result.
Hypertension makes the heart work harder to pump blood through the body. The extra workload can make the heart muscle thicken and stretch. When the heart becomes too enlarged it cannot pump enough blood. If the hypertension is not treated, the heart may fail.
The kidneys remove the body's wastes from the blood. If hypertension thickens the arteries to the kidneys, less waste can be filtered from the blood. As the condition worsens, the kidneys fail and wastes build up in the blood. Dialysis or a kidney transplant are needed when the kidneys fail. About 25% of people who receive kidney dialysis have kidney failure caused by hypertension.

Causes and symptoms

Many different actions or situations can normally raise blood pressure. Physical activity can temporarily raise blood pressure. Stressful situations can make blood pressure go up. When the stress goes away, blood pressure usually returns to normal. These temporary increases in blood pressure are not considered hypertension. A diagnosis of hypertension is made only when a person has multiple high blood pressure readings over a period of time.
The cause of hypertension is not known in 90 to 95 percent of the people who have it. Hypertension without a known cause is called primary or essential hypertension.
When a person has hypertension caused by another medical condition, it is called secondary hypertension. Secondary hypertension can be caused by a number of different illnesses. Many people with kidney disorders have secondary hypertension. The kidneys regulate the balance of salt and water in the body. If the kidneys cannot rid the body of excess salt and water, blood pressure goes up. Kidney infections, a narrowing of the arteries that carry blood to the kidneys, called renal artery stenosis, and other kidney disorders can disturb the salt and water balance.
Cushing's syndrome and tumors of the pituitary and adrenal glands often increase levels of the adrenal gland hormones cortisol, adrenalin, and aldosterone, which can cause hypertension. Other conditions that can cause hypertension are blood vessel diseases, thyroid gland disorders, some prescribed drugs, alcoholism, and pregnancy.
Even though the cause of most hypertension is not known, some people have risk factors that give them a greater chance of getting hypertension. Many of these risk factors can be changed to lower the chance of developing hypertension or as part of a treatment program to lower blood pressure.
Risk factors for hypertension include:
  • age over 60
  • male sex
  • race
  • heredity
  • salt sensitivity
  • obesity
  • inactive lifestyle
  • heavy alcohol consumption
  • use of oral contraceptives
Some risk factors for getting hypertension can be changed, while others cannot. Age, male sex, and race are risk factors that a person can't do anything about. Some people inherit a tendency to get hypertension. People with family members who have hypertension are more likely to develop it than those whose relatives are not hypertensive. People with these risk factors can avoid or eliminate the other risk factors to lower their chance of developing hypertension. A 2003 report found that the rise in incidence of high blood pressure among children is most likely due to an increase in the number of overweight and obese children and adolescents.

Diagnosis

Because hypertension doesn't cause symptoms, it is important to have blood pressure checked regularly. Blood pressure is measured with an instrument called a sphygmomanometer. A cloth-covered rubber cuff is wrapped around the upper arm and inflated. When the cuff is inflated, an artery in the arm is squeezed to momentarily stop the flow of blood. Then, the air is let out of the cuff while a stethoscope placed over the artery is used to detect the sound of the blood spurting back through the artery. This first sound is the systolic pressure, the pressure when the heart beats. The last sound heard as the rest of the air is released is the diastolic pressure, the pressure between heart beats. Both sounds are recorded on the mercury gauge on the sphygmomanometer.
Normal blood pressure is defined by a range of values. Blood pressure lower than 120/80 mm Hg is considered normal. A number of factors such as pain, stress or anxiety can cause a temporary increase in blood pressure. For this reason, hypertension is not diagnosed on one high blood pressure reading. If a blood pressure reading is 120/80 or higher for the first time, the physician will have the person return for another blood pressure check. Diagnosis of hypertension usually is made based on two or more readings after the first visit.
Systolic hypertension of the elderly is common and is diagnosed when the diastolic pressure is normal or low, but the systolic is elevated, e.g.170/70 mm Hg. This condition usually co-exists with hardening of the arteries (atherosclerosis).
Blood pressure measurements are classified in stages, according to severity:
  • normal blood pressure: less than less than 120/80 mm Hg
  • pre-hypertension: 120-129/80-89 mm Hg
  • Stage 1 hypertension: 140-159/90-99 mm Hg
  • Stage 2 hypertension: at or greater than 160-179/100-109 mm Hg
A typical physical examination to evaluate hypertension includes:
  • medical and family history
  • physical examination
  • ophthalmoscopy: Examination of the blood vessels in the eye
  • chest x ray
  • electrocardiograph (ECG)
  • blood and urine tests.
The medical and family history help the physician determine if the patient has any conditions or disorders that might contribute to or cause the hypertension. A family history of hypertension might suggest a genetic predisposition for hypertension.
The physical exam may include several blood pressure readings at different times and in different positions. The physician uses a stethoscope to listen to sounds made by the heart and blood flowing through the arteries. The pulse, reflexes, and height and weight are checked and recorded. Internal organs are palpated, or felt, to determine if they are enlarged.
Because hypertension can cause damage to the blood vessels in the eyes, the eyes may be checked with a instrument called an ophthalmoscope. The physician will look for thickening, narrowing, or hemorrhages in the blood vessels.
A chest x ray can detect an enlarged heart, other vascular (heart) abnormalities, or lung disease.
An electrocardiogram (ECG) measures the electrical activity of the heart. It can detect if the heart muscle is enlarged and if there is damage to the heart muscle from blocked arteries.
Urine and blood tests may be done to evaluate health and to detect the presence of disorders that might cause hypertension.

Treatment

There is no cure for primary hypertension, but blood pressure can almost always be lowered with the correct treatment. The goal of treatment is to lower blood pressure to levels that will prevent heart disease and other complications of hypertension. In secondary hypertension, the disease that is responsible for the hypertension is treated in addition to the hypertension itself. Successful treatment of the underlying disorder may cure the secondary hypertension.
Guidelines advise that clinicians work with patients to agree on blood pressure goals and develop a treatment plan for the individual patient. Actual combinations of medications and lifestyle changes will vary from one person to the next. Treatment to lower blood pressure may include changes in diet, getting regular exercise, and taking antihypertensive medications. Patients falling into the pre-hypertension range who don't have damage to the heart or kidneys often are advised to make needed lifestyle changes only. A 2003 report of a clinical trial showed that adults with elevated blood pressures lowered them as mush as 38% by making lifestyle changes and participating in the DASH diet, which encourages eating more fruit and vegetables.
Lifestyle changes that may reduce blood pressure by about 5 to 10 mm Hg include:
  • reducing salt intake
  • reducing fat intake
  • losing weight
  • getting regular exercise
  • quitting smoking
  • reducing alcohol consumption
  • managing stress
Patients whose blood pressure falls into the Stage 1 hypertension range may be advised to take antihypertensive medication. Numerous drugs have been developed to treat hypertension. The choice of medication will depend on the stage of hypertension, side effects, other medical conditions the patient may have, and other medicines the patient is taking.
If treatment with a single medicine fails to lower blood pressure enough, a different medicine may be tried or another medicine may be added to the first. Patients with more severe hypertension may initially be given a combination of medicines to control their hypertension. Combining antihypertensive medicines with different types of action often controls blood pressure with smaller doses of each drug than would be needed for just one.
Antihypertensive medicines fall into several classes of drugs:
Diuretics help the kidneys eliminate excess salt and water from the body's tissues and the blood. This helps reduce the swelling caused by fluid buildup in the tissues. The reduction of fluid dilates the walls of arteries and lowers blood pressure. New guidelines released in 2003 suggest diuretics as the first drug of choice for most patients with high blood pressure and as part of any multi-drug combination.
Beta-blockers lower blood pressure by acting on the nervous system to slow the heart rate and reduce the force of the heart's contraction. They are used with caution in patients with heart failure, asthma, diabetes, or circulation problems in the hands and feet.
Calcium channel blockers block the entry of calcium into muscle cells in artery walls. Muscle cells need calcium to constrict, so reducing their calcium keeps them more relaxed and lowers blood pressure.
ACE inhibitors block the production of substances that constrict blood vessels. They also help reduce the build-up of water and salt in the tissues. They often are given to patients with heart failure, kidney disease, or diabetes. ACE inhibitors may be used together with diuretics.
Alpha-blockers act on the nervous system to dilate arteries and reduce the force of the heart's contractions.
Alpha-beta blockers combine the actions of alpha and beta blockers.
Vasodilators act directly on arteries to relax their walls so blood can move more easily through them. They lower blood pressure rapidly and are injected in hypertensive emergencies when patients have dangerously high blood pressure.
Peripheral acting adrenergic antagonists act on the nervous system to relax arteries and reduce the force of the heart's contractions. They usually are prescribed together with a diuretic. Peripheral acting adrenergic antagonists can cause slowed mental function and lethargy.
Centrally acting agonists also act on the nervous system to relax arteries and slow the heart rate. They are usually used with other antihypertensive medicines.

Prognosis

There is no cure for hypertension. However, it can be well controlled with the proper treatment. Therapy with a combination of lifestyle changes and antihypertensive medicines usually can keep blood pressure at levels that will not cause damage to the heart or other organs. The key to avoiding serious complications of hypertension is to detect and treat it before damage occurs. Because antihypertensive medicines control blood pressure, but do not cure it, patients must continue taking the medications to maintain reduced blood pressure levels and avoid complications.

Prevention

Prevention of hypertension centers on avoiding or eliminating known risk factors. Even persons at risk because of age, race, or sex or those who have an inherited risk can lower their chance of developing hypertension.
The risk of developing hypertension can be reduced by making the same changes recommended for treating hypertension:
  • reducing salt intake
  • reducing fat intake
  • losing weight
  • getting regular exercise
  • quitting smoking
  • reducing alcohol consumption
  • managing stress

R.

Key terms

Arteries — Blood vessels that carry blood to organs and other tissues of the body.
Arteriosclerosis — Hardening and thickening of artery walls.
Cushing's syndrome — A disorder in which too much of the adrenal hormone, cortisol, is produced; it may be caused by a pituitary or adrenal gland tumor.
Diastolic blood pressure — Blood pressure when the heart is resting between beats.
Hypertension — High blood pressure.
Renal artery stenosis — Disorder in which the arteries that supply blood to the kidneys constrict.
Sphygmomanometer — An instrument used to measure blood pressure.
Systolic blood pressure — Blood pressure when the heart contracts (beats).
Vasodilator — Any drug that relaxes blood vessel walls.
Ventricle — One of the two lower chambers of the heart.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
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Most people with high blood pressure have no signs or symptoms, even if blood pressure readings reach dangerously high levels.
A few people with high blood pressure may have headaches, shortness of breath or nosebleeds, but these signs and symptoms aren't specific and usually don't occur until high blood pressure has reached a severe or life-threatening stage
 High blood pressure
High blood pressure is often associated with few or no symptoms. Many people have it for years without knowing it.
However, just because high blood pressure is often symptomless doesn’t mean it’s harmless. In fact, uncontrolled high blood pressure, or hypertension, causes damage to your arteries, especially those in the kidneys and eyes. High blood pressure is also a risk factor for stroke, heart attack, and other cardiovascular problems.
High blood pressure is generally a chronic condition. There are two major categories of high blood pressure: secondary hypertension and primary hypertension. Most people have primary hypertension, otherwise known as essential hypertension.
  • Secondary hypertension is high blood pressure that is the direct result of a separate health condition.
  • Primary hypertension is high blood pressure that doesn’t result from a specific cause. Instead, it develops gradually over time. Many such cases are attributed tohereditary factors.
Typically, the only way to know you have hypertension is to get your blood pressure tested.
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Rare symptoms and emergency symptoms
Rarely, people with chronic high blood pressure might have symptoms such as:
When symptoms do occur, it’s usually only when blood pressure spikes suddenly and extremely enough to be considered a medical emergency. This is called a hypertensive crisis.
Hypertensive crisis is defined as ablood pressure reading of 180 milligrams of mercury (mm Hg) or above for the systolic pressure (first number) or 120 or above for the diastolic pressure (second number). It’s often caused by skipping medications or secondary high blood pressure.
If you’re checking your own blood pressure and get a reading that high, wait a few minutes and then check again to make sure the first reading was accurate. Other symptoms of a hypertensive crisis may include:
After waiting a few minutes, if your second blood pressure reading is still 180 or above, don’t wait to see whether your blood pressure comes down on its own. Call 911 or your local emergency services immediately.
Emergency hypertensive crisis can result in severe complications, including:
High blood pressure during pregnancy
In some cases, high blood pressure can occur during pregnancy. There are several types of high blood pressure disorders in pregnancy. Causes may be due to a number of factors, including:
If high blood pressure occurs during pregnancy after 20 weeks, a condition known as preeclampsia may develop. Severe preeclampsia can cause damage to the organs and brain, which can bring on life-threatening seizures known as eclampsia.
Signs and symptoms of preeclampsia include protein in urine samples, intense headaches, and vision changes. Other symptoms are abdominal pain and excessive swelling of the hands and feet.
High blood pressure during pregnancy can cause a premature birth or early detachment of the placenta. It may also require a cesarean delivery.
In most cases, the blood pressure will return to normal after giving birth.
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Complications and risks of high blood pressure
Over time, untreated high blood pressure can cause heart disease andrelated complications such as heart attack, stroke, and heart failure.
Other potential problems are:
Treatment for high blood 
 



Simple lifestyle changes can often help reduce high blood pressure (hypertension), although some people may need to take medication as well.
Your GP can advise you about changes you can make to your lifestyle and discuss whether they think you would benefit from medication.

Lifestyle changes

There are some changes you could make to your lifestyle to reduce high blood pressure. Some of these will lower your blood pressure in a matter of weeks, while others may take longer.
These include:
You can take these steps today, regardless of whether or not you're taking blood pressure medication. In fact, by making these changes early on you may be able to avoid needing medication.

Medication for high blood pressure

Several medications can be used to help control high blood pressure. Many people need to take a combination of different medicines.
The medication recommended for you at first will depend on your age and ethnicity:
  • if you're under 55 years of age – you'll usually be offered an ACE inhibitor or an angiotensin-2 receptor blocker (ARB)
  • if you're aged 55 or older, or you're any age and of African or Caribbean origin – you'll usually be offered a calcium channel blocker
You may need to take blood pressure medication for the rest of your life. But your doctor might be able to reduce or stop your treatment if your blood pressure stays under control for several years.
It's really important to take your medications as directed. If you miss doses, it won't work as effectively. The medication won't necessarily make you feel any different, but this doesn't mean it's not working.
Medications used to treat high blood pressure can have side effects, but most people don't experience any. If you do, changing medication will often help.

ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors reduce blood pressure by relaxing your blood vessels.
Common examples are enalapril, lisinopril, perindopril and ramipril.
The most common side effect is a persistent dry cough. Other possible side effects include headaches, dizziness and a rash.

Angiotensin-2 receptor blockers (ARBs)

ARBs work in a similar way to ACE inhibitors. They're often recommended if ACE inhibitors cause troublesome side effects.
Common examples are candesartan, irbesartan, losartan, valsartan and olmesartan.
Possible side effects include dizziness, headaches, and cold or flu-like symptoms.

Calcium channel blockers

Calcium channel blockers reduce blood pressure by widening your blood vessels.
Common examples are amlodipine, felodipine and nifedipine. Other medicines such as diltiazem and verapamil are also available.
Possible side effects include headaches, swollen ankles and constipation.
Drinking grapefruit juice while taking some calcium channel blockers can increase your risk of side effects.

Diuretics

Sometimes known as water pills, diuretics work by flushing excess water and salt from the body through urine. They're often used if calcium channel blockers cause troublesome side effects.
Common examples are indapamide and bendroflumethiazide.
Possible side effects include dizziness when standing up, increased thirst, needing to go to the toilet frequently, and a rash.
Low potassium level (hypokalaemia) and low sodium level (hyponatraemia) may also be seen after long-term use.

Beta-blockers

Beta-blockers can reduce blood pressure by making your heart beat more slowly and with less force.
They used to be a popular treatment for high blood pressure, but now only tend to be used when other treatments haven't worked.
This is because beta-blockers are considered less effective than other blood pressure medications.
Common examples are atenolol and bisoprolol.
Possible side effects include dizziness, headaches, tiredness, and cold hands and feet to

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