Saturday, May 19, 2012

High Blood Pressure(Hypertension)

High Blood Pressure Overview

(A silent killer)

                The heart pumps blood into the arteries with enough force to push blood to the far reaches of each organ from the top of the head to the bottom of the feet. Blood pressure can be defined as the pressure of blood on the walls of the arteries as it circulates through the body. Blood pressure is highest as its leaves the heart through the aorta and gradually decreases as it enters smaller and smaller blood vessels (arteries, arterioles, and capillaries). Blood returns in the veins leading to the heart, aided by gravity and muscle contraction.
                      Picture of the blood pressure and circulatory system
Hypertension is the medical term for high blood pressure. It is known as the "silent killer" since it has no initial symptoms but can lead to long-term disease and complications..
  • Many people have high blood pressure and don't know it.
  • Important complications of uncontrolled or poorly treated high blood pressure include heart attackcongestive heart failurestrokekidney failureperipheral artery disease, and aortic aneurysms (weakening of the wall of the aorta, leading to widening or ballooning of the aorta).
  • Public awareness of these dangers has increased. High blood pressure has become the second most common reason for medical office visits in the United States.
How is blood pressure measured?
Blood pressure is measured with a blood pressure cuff and recorded as two numbers, for example, 120/80 mm Hg (millimeters of mercury). Blood pressure measurements are usually taken at the upper arm over the brachial artery.
  • The top, larger number is called the systolic pressure. This measures the pressure generated when the heart contracts (pumps). It reflects the pressure of the blood against arterial walls.
  • The bottom, smaller number is called the diastolic pressure. This reflects the pressure in the arteries while the heart is filling and resting between heartbeats.
                                    Picture of diastolic and systolic blood pressure
The American Heart Association has recommended guidelines to define normal and high blood pressure.
  • Normal blood pressure less than 120/80
  • Pre-hypertension 120-139/ 80-89
  • High blood pressure (stage 1) 140-159/90-99
  • High blood pressure (stage 2) higher than 160/100
As many as 60 million Americans have high blood pressure.
  • Uncontrolled high blood pressure may be responsible for many cases of death and disability resulting from heart attack, stroke, and kidney failure.
  • According to research studies, the risk of dying of a heart attack is directly linked to high blood pressure, particularly systolic hypertension. The higher your blood pressure, the higher the risk. Maintaining lifelong control of hypertension decreases the future risk of complications such as heart attack and stroke.

High Blood Pressure Causes

In 90% of people with hypertension, the cause of high blood pressure is not known and is referred to as primary or essential hypertension. While the specific cause is unknown, there are risk factors that can contribute to developing high blood pressure.
Factors that can not be changed
  • Age:   The older a person is, the greater the likelihood that he or she will develop high blood pressure, especially elevated systolic readings. This is largely due to arteriosclerosis, or "hardening of the arteries."

  • Race:   African Americans develop high blood pressure more often than Caucasians. They develop high blood pressure at a younger age and develop more severe complications sooner in life. 

  • Socioeconomic status:    High blood pressure is found more commonly among the less educated and lower socioeconomic groups. Residents of the southeastern United States, both Caucasian and African American, are more likely to have high blood pressure than residents of other regions.
  • Family history (heredity):    The tendency to have high blood pressure appears to run in families. 
  • Gender:              Generally men have a greater likelihood of developing high blood pressure than women. This likelihood varies according to age and among various ethnic groups.

Factors that can be changed

  • Obesity:                   

 As body weight increases, the blood pressure rises. Obesity is defined as having a body mass index (BMI) greater than 30 kg/m. A BMI of 25-30 kg/m is considered overweight (BMI=weight in pounds x 703/ height in inches ) Being overweight increases the risk of high blood pressure. Health care practitioners recommend that all 
obese people with high blood pressure lose weight until they are within 15% of their healthy body weight.

  • Obese people are two to six times more likely to develop high blood pressure than people whose weight is within a healthy range.
  • Not only the degree of obesity is important, but also the manner in which the body accumulates extra fat. Some people gain weight around their belly (central obesity or "apple-shaped" people), while others store fat around their hips and thighs ("pear-shaped" people). "Apple-shaped" people tend to have greater health risks for high blood pressure than "pear-shaped" people.

  • Sodium (salt) sensitivity:         
                                 Some people have high sensitivity to sodium (salt), and their blood pressure increases if they use salt. Reducing sodium intake tends to lower their blood pressure. Americans consume 10-15 times more sodium than they need. Fast foods and processed foods contain particularly high amounts of sodium. Many over-the-counter medicines also contain large amounts of sodium. Read food labels and learn about salt content in foods and other products as a healthy first step to reducing salt intake. Fast food restaurants also make the salt and calorie content of their food available to consumers at their restaurants,

  • Alcohol use:                       
Drinking more than one to two drinks of alcohol per day tends to raise blood pressure in those who are sensitive to alcohol. 

  • Birth control pills (oral contraceptive use): 

Some women who take birth control pills develop high blood pressure. 

  • Lack of exercise (physical inactivity):      

A sedentary lifestyle contributes to the development of obesity and high blood pressure. 

  • Medications:             
Certain drugs, such as amphetamines (stimulants), diet pills, and some medications used for cold and allergy symptoms such aspseudoephedrine, tend to raise blood pressure.

High Blood Pressure Symptoms

           High blood pressure usually causes no symptoms and 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 markedly elevated blood pressure may develop:





Blurred vision

Nausea and vomiting 

chest pain and shortness of breath.

People often do not seek medical care until they have symptoms arising from the organ damage 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 transient ischemic attack (TIA)
  • Kidney failure
  • Eye damage with progressive vision loss
  • Peripheral arterial disease causing leg pain with walking (claudication)
  • 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, lightheadedness, nausea, vomiting, and stroke like symptoms
  • Malignant hypertension requires emergency intervention 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.

High Blood Pressure Diagnosis


Blood pressure is measured with a blood pressure cuff (sphygmomanometer). This may be done using a stethoscope and a cuff and gauge or by an automatic machine. It is a routine part of the physical examination and one of the vital signs often recorded for a patient visit. Other vital signs include pulse rate, respiratory rate (breathing rate), temperature, and weight.
When discussing blood pressure issues, the health care practitioner may ask questions about past medical history, family history, and medication use, including prescriptions, over-the-counter medications, herbal remedies, and food additives. Other questions may include lifestyle habits, including activity levels,smoking, alcohol consumption, and illegal drug use.
Physical examination may include listening to the heart and lungs, feeling for pulse in the wrist and ankles, and feeling and listening to the abdomen looking for signs of an enlarged aorta. Eye examination with an ophthalmoscope may be helpful by looking at the small blood vessels on the retina in the back of the eyeball.
  • Normal Blood Pressure

    • Systolic less than 120 mm Hg; diastolic less than 80 mm Hg
  • Prehypertension

    • Systolic 120-139 or diastolic 80-89 mm Hg

  • High Blood Pressure
    • Stage 1: Systolic 140-159; diastolic 90-99 mm Hg
    • Stage 2: Systolic more than 160; diastolic more than 100 mm Hg
Blood tests may be considered to assess risk factors for heart disease and stroke as well as looking for complications of hypertension. These include complete blood count (CBC), electrolytes, BUN (blood urea nitrogen), and creatinine and GFR (glomerular filtration rate) to measure kidney function. A fasting lipid profile will measure cholesterol and triglyceride levels in the blood. If appropriate, blood tests may be considered to look for an underlying cause of high blood pressure includingabnormal thyroid or adrenal gland function.
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.
Other studies may be considered depending upon the individual patient's needs
  • Electrocardiogram (ECG) may help evaluate heart rate and rhythm. It is a screening test to help assess heart muscle thickness. If hypertension is long-standing, the heart muscle has to hypertrophy, or get larger, to push blood against the increased pressure within the arteries of the body.  
  • Echocardiogram is an ultrasound examination of the heart It is used to evaluate the anatomy and the function of the heart. A cardiologist is required to interpret this test and can evaluate the heart muscle and determine how thick it is, whether it moves appropriately, and how efficiently it can push blood out to the rest of the body. The echocardiogram can also assess heart valves, looking for narrowing (stenosis) and leaking (insufficiency or regurgitation). A chest X-ray may be used as a screening test to look for heart size, the shape of the aorta, and to assess the lungs.

  • 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 measure blood flow in the arteries to both kidneys and sometimes depicts narrowings that can lead to high blood pressure in a minority of patients.