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While the cure for any given disease is more or less similar, there is a huge difference in the cost of treatment thanks to the price difference between generic and branded drugs. 
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Monday 16 April 2012

What Is High Blood Pressure? What Causes High Blood Pressure?

What Is High Blood Pressure? What Causes High Blood Pressure?


Editor's Choice
Main Category: Hypertension
Also Included In: Cardiovascular / Cardiology
Article Date: 30 Jul 2009 - 2:00 PST

High blood pressure is also known as hypertension. Blood pressure is the amount of force exerted against the walls of the arteries as blood flows through them - if a person has high blood pressure it means that the walls of the arteries are receiving too much pressure repeatedly - the pressure needs to be chronically elevated for a diagnosis of hypertension to be confirmed. In medicine chronic means for a sustained period; persistent.

In the USA approximately 72 million people have hypertension - about 1 in every 3 adults, according to the National Heart Lung and Blood Institute. The National Health Service, UK, estimates that about 40% of British adults have the condition. The National Institutes of Health (NIH) estimates that about two-thirds of people over the age of 65 in the USA have high blood pressure.


The heart is a muscle that pumps blood around the body constantly - during every second of our lives. Blood that has low oxygen levels is pumped towards the lungs, where oxygen supplies are replenished. The oxygen rich blood is then pumped by the heart around the body to supply our muscles and cells. The pumping of blood creates pressure - blood pressure.

When we measure blood pressure, we gauge two types of pressure:
  • Systolic pressure - the blood pressure when the heart contracts, specifically the moment of maximum force during the contraction. This happens when the left ventricle of the heart contracts.
  • Diastolic pressure - the blood pressure between heartbeats, when the heart is resting and dilating (opening up, expanding).
When a person's blood pressure is taken the doctor or nurse needs to measure both the systolic and diastolic pressures. The figures usually appear with a larger number first (systolic pressure), followed by a smaller number (diastolic pressure). The figure will be followed by the abbreviation "mmHg", which means millimeters of mercury.



The definition of high blood pressure (hypertension)

Anyone whose blood pressure is 140/90mmhg or more for a sustained period is said to have high blood pressure, or hypertension.

Blood pressure is usually divided into five categories:
  • Hypotension (low blood pressure)
    Systolic mmHg 90 or less, or
    Diastolic mmHg 60 or less
  • Normal
    Systolic mmHg 90-119, and
    Diastolic mmHg 60-79
  • Prehypertension
    Systolic mmHg 120-139, and
    Diastolic mmHg 80-89
  • Stage 1 Hypertension
    Systolic mmHg 140-159, and
    Diastolic mmHg 90-99
  • Stage 2 Hypertension
    Systolic mmHg over 160, and
    Diastolic mmHg over 100

What are the symptoms of high blood pressure (hypertension)?

Most people with high blood pressure will not experience any symptoms until levels reach about 180/110 mmHg. When symptoms do appear, they typically include:
  • Headache - usually, this will last for several days.
  • Nausea - a sensation of unease and discomfort in the stomach with an urge to vomit.
  • Vomiting - less common than just nausea.
  • Dizziness - Lightheadedness, unsteadiness, and vertigo.
  • Blurred or double vision (diplopia).
  • Epistaxis - nosebleeds.
  • Palpitations - disagreeable sensations of irregular and/or forceful beating of the heart.
  • Dyspnea - breathlessness, shortness of breath.
Anybody who experiences these symptoms should see their doctor immediately.

Children with hypertension may have the following signs and symptoms:
  • Headache.
  • Fatigue.
  • Blurred vision.
  • Nosebleeds.
  • Bell's palsy - inability to control facial muscles on one side of the face.
Newborns and very young babies with hypertension may have the following signs and symptoms:
  • Failure to thrive.
  • Seizure.
  • Irritability.
  • Lethargy.
  • Respiratory distress.
People who are diagnosed with high blood pressure should have their blood pressure checked frequently. Even if yours is normal, you should have it checked at least once every five years, and more often if you have any contributory factors.

What are the causes of high blood pressure?

When referring to the causes of hypertension, it is divided into two categories:
  • Essential high blood pressure (primary high blood pressure) - no cause has been identified.
  • Secondary high blood pressure - the high blood pressure has an underlying cause, such as kidney disease, or a specific medication the patient is taking.
Even though there is no identifiable cause for essential high blood pressure, there is strong evidence linking some risk factors to the likelihood of developing the condition. Most of the causes below are essential high blood pressure risk factors; there are also a couple of secondary high blood pressure examples:
  • Age - the older you are the higher the risk.
  • Family history - if you have close family members with hypertension, your chances of developing it are significantly higher. An international scientific study involving over 150 scientists from 93 centers in Europe and the USA identified eight common genetic differences which may increase the risk of high blood pressure.
  • Temperature - A study which monitored 8801 participants over the age of 65 in three French cities, found that systolic and diastolic blood pressure values differed significantly across the four seasons of the year and according to the distribution of outdoor temperature. Blood pressure was lower when it got warmer, and rose when it got colder.
  • Ethnic background - evidence in Europe and North America indicates that people with African and/or South Asian ancestry have a higher risk of developing hypertension, compared to people with predominantly Caucasian or Amerindian (indigenous of the Americas) ancestries.
  • Obesity/overweight - overweight refers to having extra body weight from muscle, bone, fat and/or water. Obesity tends to refer just to having a high amount of extra body fat. Both overweight and obese people are more likely to develop high blood pressure, compared to people of normal weight.
  • Some aspects of gender - in general, high blood pressure is more common among adult men than adult women. However, after the age of 60 both men and women are equally susceptible. Women aged 18-59 are more likely to identify the signs and symptoms and subsequently to seek treatment for high blood pressure, compared to men.
  • Physical inactivity - lack of exercise, as well as having a sedentary lifestyle, raises the risk of hypertension.
  • Smoking - smoking causes the blood vessels to narrow, resulting in higher blood pressure. Smoking also reduces the blood's oxygen content so the heart has to pump faster in order to compensate, causing a rise in blood pressure.
  • Alcohol intake - the risk may even sometimes include people who drink regularly, but not in excess. People who drink regularly have higher systolic blood pressure than people who do not, say researchers from the University of Bristol, UK. They found that systolic blood pressure levels are about 7 mmHg higher in frequent drinkers than in people who do not drink.
  • High salt intake - researchers from the University of Michigan Health System reported that societies where people don't eat much salt have lower blood pressures than places where people eat a lot of salt.
  • High fat diet - many health professionals say that a diet high in fat leads to a raised high blood pressure risk. However, most dietitians stress that the problem is not how much fat is consumed, but rather what type of fats. Fats sourced from plants, such as avocados, nuts, olive oil, etc., as well as omega oils which are common in some types of fish, are good for you - while, saturated fats which are common in animal sourced foods, as well as trans fats are bad for you.
  • Mental stress - various studies have compelling evidence that mental stress, especially over the long term, can have a serious impact on blood pressure. An interesting study carried out by researchers at the University of Texas, suggested that how air traffic controllers handle stress can affect whether they are at risk of developing high blood pressure later in life. In view of this study, and many others that focus on stress management, it would be fair to assume that some levels of stress which are not managed properly can raise the risk of hypertension.
  • Diabetes - people with diabetes are at a higher risk of developing hypertension. Among patients with diabetes type 1, hyperglycemia (high blood sugar) is a risk factor for incident hypertension in type 1 diabetes - intensive insulin therapy reduces the long-term risk of developing hypertension. People with diabetes type 2 are at risk of hypertension due to hyperglycemia, as well as other factors, such as overweight/obesity, certain medications, and some cardiovascular diseases.
  • Psoriasis - An American study that followed 78,000 women for 14 years found that having psoriasis was linked to a higher risk of developing high blood pressure and diabetes. Psoriasis is an immune system condition that appears on the skin in the form of thick, red scaly patches.
  • Low birth weight - the link between low birth weight and hypertension becomes stronger as individuals get older - especially among white males, as opposed to female and males and female of Afro-Americans, scientists at the Tulane Center for Cardiovascular Health, New Orleans reported.
  • Pregnancy - pregnant women have a higher risk of developing hypertension than women of the same age who are not pregnant. It is the most common medical problem encountered during pregnancy, complicating 2% to 3% of all pregnancies. Most countries divide hypertensive disorders in pregnancy into four categories: 1. Chronic hypertension, 2. Preeclampsia-eclampsia, 3. Preeclampsia superimposed on chronic hypertension. 4. Gestational hypertension.

How is high blood pressure diagnosed?


  • Sphygmomanometer

    Most lay people have seen this device. It consists of an inflatable cuff that is wrapped around the upper arm. When the cuff is inflated it restricts the blood flow. A mercury or mechanical manometer measures the pressure.

    A sphygmomanometer is always used together with a means to determine at what pressure blood flow is just starting, and at what pressure it is unimpeded. For example, a manual sphygmomanometer is used together with a stethoscope.

    • The cuff is placed snugly and smoothly around the upper arm, at approximately the same altitude as the heart while the patient is sitting up with the arm supported (resting on something). It is crucial that the size of the cuff is appropriate. If it is too small the reading will be inaccurately high; if it is too large the reading will be too low.
    • The cuff is inflated until the artery is completely obstructed (occluded).
    • The nurse, doctor, or whoever is doing the examination listens with a stethoscope to the brachial artery at the elbow and slowly releases the cuff's pressure (deflates it).
    • As the cuffs pressure falls the examiner will hear a whooshing sound or a pounding sound when blood flow starts again.
    • The pressure at the point when the sound began is noted down and recorded as the systolic blood pressure.
    • The cuff is deflated further until no sound can be heard. At this point the examiner notes down and records the diastolic blood pressure.
    With a digital sphygmomanometer everything is done with electrical sensors.
  • Hypertension confirmation requires several readings

    One blood pressure reading is not enough to diagnose hypertension in a patient. People's blood pressure can vary during the day, a visit to the doctor may spike the reading because the patient is anxious or stressed, having just eaten may also temporarily affect blood pressure readings.

    As the definition of hypertension is defined as "repeatedly elevated blood pressure" the GP (general practitioner, primary care physician) will have to take several readings over a set period. This may require three separate measurements one week apart - often the monitoring goes on for much longer before a diagnosis is confirmed. On some rare occasions, if the blood pressure is extremely high, or end-organ damage is present, diagnosis may be made immediately so that treatment can start promptly. End-organ damage generally refers to damage to major organs fed by the circulatory system, such as the heart, kidneys, brain or eyes.
  • Kidney disorder - if the patient has a urinary tract infection, urinates frequently, or reports pain down the side of the abdomen, they could be signs/symptoms of a kidney disorder. If the doctor places the stethoscope on the side of the abdomen and hears the sound of a rush of blood (a bruit), it could be a sign of stenosis - a narrowing of an artery supplying the kidney.
The doctor may also order the following tests:
  • Urine and blood tests - underlying causes might be due to cholesterol, high potassium levels, blood sugar, infection, kidney malfunction, etc. Protein or blood in urine may indicate kidney damage. High glucose in the blood may indicate diabetes.
  • Exercise stress test - more commonly used for patients with borderline hypertension. This usually involves pedaling a stationary bicycle or walking on a treadmill. The stress test assesses how the body's cardiovascular system responds to increased physical activity. If the patient has hypertension this data is important to know before the exercise test starts. The test monitors the electrical activity of the heart, as well as the patient's blood pressure during exercise. An exercise stress test sometimes reveals problems that are not apparent when the body is resting. Imaging scans of the heart's blood supply might be done at the same time.
  • ECG (electrocardiogram) - this tests the heart's electrical activity. This test is more commonly used for patients at high risk of heart problems, such as hypertension and elevated cholesterol levels. The initial ECG is called a baseline. Subsequent ECGs may be compared with the baseline to reveal changes which may point to coronary artery disease or thickening of the heart wall.
  • Holter monitoring - the patient carries an ECG portable device for about 24 hours.
  • Echocardiogram - this device uses ultrasound waves which show the heart in motion. The doctor will be able to detect problems, such as thickening of the heart wall, defective heart valves, blood clots, and excessive fluid around the heart.

What is the treatment for high blood pressure (hypertension)?

Treatment for hypertension depends on several factors, such its severity, associated risks of developing stroke or cardiovascular, disease, etc.
  • Slightly elevated blood pressure

    The doctor may suggest some lifestyle changes if the patient's blood pressure is only slightly elevated and the risk of developing cardiovascular disease considered to be small.
  • Moderately high blood pressure

    If the patient's blood pressure is moderately high and the doctors believes the risk of developing cardiovascular disease during the next ten years is above 20%, the patient will probably be prescribed medication and advised on lifestyle changes.
  • Severe hypertension

    If blood pressure levels are 180/110 mmHg or higher, the doctor will refer the patient to a specialist (cardiologist).
Changes in lifestyle that can help lower high blood pressure

Medications for treating hypertension

There are several anti-hypertensive medications on the market today. Some patients may need to take a combination of different drugs to effectively control their high blood pressure.

Some patients may have to be on medication to control hypertension for the rest of their lives. Doctors may advise discontinuing treatment if the patient has managed to maintain good blood pressure levels for a given period, and is not considered to be at significant risk of stroke or cardiovascular disease.

In a study, scientists from the Robarts Research Institute at The University of Western Ontario found that patients actually have more control of their high blood pressure when treated with less medication.

Below are some details of the most common drugs:
  • Angiotensin-converting enzyme (ACE) inhibitors

    ACE inhibitors block the actions of some hormones, such as angiotensin II, that regulate blood pressure. Angiotensin II causes the arteries to constrict, and increases blood volume, resulting in increased blood pressure. By inhibiting the actions of angiotensin II, the ACE inhibitors help reduce blood volume and also widen the arteries, both of which will cause the blood pressure drop.

    People with a history of heart disease, pregnant women or individuals with conditions that affect the blood supply to the kidneys should not take ACE inhibitors.

    Doctors may order a blood test to determine whether the patient has any pre-existing kidney problems. ACE inhibitors can reduce the blood supply to the kidneys, making them less efficient. Regular blood tests are usually carried out on patients taking ACE inhibitors.

    ACE inhibitors may have the following more common side effects, which usually go away after a few days:

    • Dizziness
    • Fatigue
    • Weakness
    • Headaches
    • Persistent dry cough (some people find the dry cough may continue)

    Some patients may find the side effects too unpleasant or long-lasting. In such cases doctors will switch to an angiotensin-2 receptor antagonist. Side effects are less common, but may include dizziness, headache and/or hyperkalemia (elevated blood level of the electrolyte potassium).

    Drug interaction - the effects of ACE inhibitors may be altered if taken with others medications, including some OTC (over-the-counter, non-prescription) drugs.
  • Calcium channel blockers

    Calcium channel blockers (CCBs), among other things, decrease the calcium in blood vessels. A drop in calcium relaxes the vascular smooth muscle so that it does not contract so strongly, resulting in vasodilation (widening of arteries). If the arteries are wider blood pressure will drop.

    Patients with a history of heart disease, liver disease, or problems with circulation should not take calcium channel blockers.

    Calcium channel blockers may have the following more common side effects, which usually go away after a few days:

    • Flushing - redness of the skin, usually over the cheeks or neck
    • Headaches
    • Edema (swelling) - swollen ankles, feet, and more rarely the abdomen
    • Dizziness
    • Fatigue
    • Skin rash

    Drug interaction - patients taking calcium channel blockers should avoid grapefruit.
  • Thiazide diuretics

    Thiazide diuretics act on the kidneys to help the body eliminate sodium and water, resulting in less blood volume - less blood volume results in lower blood pressure. They are often the first choice in high blood pressure medications (but not the only choice).

    Thiazide diuretics may cause the following side effects, some of which may persist:

    • Hypokalemia - low blood potassium which can affect kidney and heart functions.
    • Impaired glucose tolerance - raising risk of diabetes.
    • Impotence (erectile dysfunction) - the side-effect resolves once the medication is withdrawn.

    Patients taking thiazide diuretics should have regular blood and urine tests in order to monitor blood sugar and potassium levels.

    Patients aged 80 or over may be given indapamide (Lozol), a special type of thiazide diuretic which helps reduce death from stroke, heart failure and some other cardiovascular diseases.
  • Beta-blockers

    Beta-blockers were once very widely used for the treatment of hypertension. Because they have more potential side effects than other current hypertensive drugs, they tend to be used today when other treatments have not worked. Beta blockers slow the heart rate down, as well as reducing the force of the heart, resulting in a drop in blood pressure.

    Beta blockers may have the following side effects:

    • Fatigue.
    • Cold hands and feet.
    • Slow heartbeat.
    • Nausea.
    • Diarrhea. The side effects below are also possible, but less common:
    • Disturbed sleep - beta-blockers decrease nocturnal melatonin release.
    • Nightmares.
    • Erectile dysfunction - difficulty in achieving or sustaining an erection.

    Drug interaction - the effects of beta-blockers may be altered if the patient takes some other medicines at the same time, causing adverse side-effects.
  • Renin inhibitors

    Aliskiren (Tekturna, Rasilez) reduces renin production. Renin is an enzyme produced in the kidneys. Renin is involved in the production of a substance in the body called angiotensin I. Angiotensin I is converted into the hormone angiotensin II, which narrows blood vessels. Aliskiren blocks the production of angiotensin I so that levels of both angiotensin I and angiotensin II fall. This causes widening of the blood vessels, resulting in a drop in blood pressure. As it is a relatively new medication its use and dosages for patients with hypertension are still being determined.

    Tekturna was approved in the US in March 2007 and in the European Union in August 2007 under the trade name Rasilez. Tekturna HCT, the first single-pill combination involving Tekturna, was approved in the US in January 2008. The single-pill combination Rasilez HCT was approved by the European Commission in January 2009. Rasilez is approved in over 70 countries.

    Aliskiren may have the following side effects:

    • Diarrhea
    • Dizziness
    • Flu-like symptoms
    • Fatigue
    • Cough

    In February, 2009, the European Medicines Agency (EMEA) recommended adding a contra-indication to the Product Information for aliskiren, stating that it must not be used in patients who have experienced angioedema (swelling of the tissues beneath the skin).
Effectiveness of medications may vary according to patient's ethnicity

ACE inhibitors have been found to be more effective as a first choice medication in Caucasian patients, while calcium channel blockers or thiazide diuretics are generally more effective as a first choice medication for Afro-American and Afro-Caribbean patients, according to data from the USA and the UK.

If the above-mentioned medications, and their combinations are not effective

Some patients may still have trouble reaching desirable levels of blood pressure after being treated with the drugs mentioned so far. If this happens, the doctor may prescribe:
  • Alpha blockers - they reduce the effects of natural chemicals that constrict (narrow) the blood vessels by reducing nerve impulses to the blood vessels.
  • Alpha-beta blockers - they slow the heartbeat, which reduces the amount of blood pumping through the blood vessels, as well as reducing nerve impulses to the blood vessels.
  • Central-acting agents - they stop the brain from telling the nervous system to raise the heart rate and constrict blood vessels.
In order to reduce the risk of cardiovascular disorder, some doctors may ask their patients to take daily aspirin.

What are the complications of high blood pressure (hypertension)?

If the hypertension is not treated or controlled the excessive pressure on the artery walls can lead to damage of the blood vessels (cardiovascular disease), as well as vital organs. The extent of damage depends on two factors; the severity of the hypertension and how long it goes on for untreated.

Below is a list of some of the possible complications:
  • Stroke - blood flow to the brain is impaired by blockage or rupture of an artery to the brain, and brain cells die.
  • Heart attack - heart muscle dies due to a loss of blood supply.
  • Heart failure - the heart struggles to pump enough blood to meet the needs of the whole body. This happens because after pumping blood against higher pressure into the blood vessels the heart muscle thickens.
  • Blood clot - some blood converts from a liquid into a solid (thrombus). Some blood clots can cause serious complications.
  • Aneurysm - a bulge forms on the wall of a vein, artery or the heart. The wall is weakened and may rupture.
  • Kidney disease - hypertension often damages the small blood vessels in the kidneys, resulting in kidneys that do not work properly. Eventually the kidneys can fail completely (kidney failure).
  • Eyes (hypertensive retinopathy) - untreated hypertension can lead to thickened, narrowed or torn blood vessels in the eyes, which can lead to vision loss.
  • Metabolic syndrome - this is a disorder of the body's metabolism, including an enlarged waistline, low blood HDL levels (the good cholesterol), hypertension, and high levels of insulin. If the patient has hypertension he/she is more likely to have other components of metabolic syndrome, significantly raising the risk of diabetes, stroke and heart disease.
  • Cognitive and memory problems - if the high blood pressure continues untreated the patient's ability to remember things, learn and understand concepts may be eventually become affected.
Written by Christian Nordqvist

Source : http://www.medicalnewstoday.com/articles/159283.php

Sunday 8 January 2012

Investigating heart disease

Blood tests

These can pick up abnormalities that influence how well the heart is working. For example, they can detect raised levels of cholesterol (which may lead to coronary artery disease), abnormal levels of thyroid hormones (which can affect the heart's strength and rhythm) and the presence of cardiac enzymes (chemicals released when heart muscle cells are damaged in a heart attack).
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Cardiac enzyme tests

Blood samples taken over a series of days can reveal the level of enzymes - proteins that help with chemical actions in the body and are released after a heart attack - in the blood.
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Cerebral arteriography

This is used to show the extent and location of hardening of the arteries in the brain in order to diagnose patients at risk of stroke. The test takes between 20 minutes and an hour and is often done as day case, though some patients may have a short stay in hospital. There is a very small risk - one in 700 - that the test will cause a heart attack.
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Chest x-ray

This shows abnormalities in the size or shape of the heart, and whether fluid is building up in the lungs because the heart isn't working efficiently as a pump.
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Coronary angiogram

This is often used to assess whether people with angina require surgery. The test gives vital information about:
  • Blood pressure within the heart
  • How much oxygen is in the blood
  • The function of the pumping chambers and valves
  • The exact severity and positioning of any narrowings in the coronary arteries
A catheter is inserted into a vein or artery in the groin or arm, under a local anaesthetic, and dye is injected into the coronary arteries. Obstructions in the arteries can be identified by tracing the liquid's passage though the veins.
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Coronary angiography

This is a more complex test. Under the guidance of an x-ray camera, a long, thin tube is threaded into the coronary arteries via a blood vessel in the groin or arm and a dye, which can be seen on the x-ray screen, is then injected, showing the pattern of the coronary arteries.
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CT scan

High resolution images of the heart, brain and blood vessels are given by X-ray computed tomography (CT) or computerised axial tomographic (CAT) scans. It's useful to evaluate disease of the aorta - the largest artery in the body and involves little potential risk to patients. In stroke patients, it gives valuable information about the location and extent of brain injury.
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Doppler studies and echocardiography

Blood samples taken over a series of days can reveal the level of enzymes - proteins that help with chemical actions in the body and are released after a heart attack - in the blood.
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Echocardiogram

This scan uses sound waves to create an image of the heart as it beats. It shows the structure of the heart, how the walls of the heart move, and how well the heart valves are working.
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Echocardiography

A pulse of high frequency, inaudible sound is transmitted through the skin by placing a recorder or probe on the chest wall. The probe picks up the echoes reflected from various parts of the heart and displays them as an echocardiogram - a picture on a screen. The recorded waves show the shape, texture and movement of the valves and the size and function of the heart muscle and chambers. The test can take up to an hour and is painless. It provides information about disease of the heart muscle for those who have suffered a heart attack or heart failure and to assess people with disease of the heart valves.
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Electrocardiogram (ECG)

This shows electrical activity in the heart. It can reveal the thickness of the heart muscle (this may indicate long-term strain due to high blood pressure), areas of damage after a heart attack, and whether the blood supply to the heart muscle is adequate.
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Exercise stress test (or treadmill test)

This monitors the heart during exercise and shows how well it responds when the demands on it are increased. It's a good way to detect blockages in the blood flow through the coronary arteries to the muscle of the heart (coronary artery disease).
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Holter monitoring

Also known as 24-hour ECG, involves electrocardiogram recordings taken over 24 hours and can help diagnose palpitations, which occur infrequently and can easily be missed in a short test. The electrodes are placed on the chest and attached with wires to a small portable tape recorder which is worn on a belt around the waist. The recorder - the Holter monitor - takes constant or intermittent readings.
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MRI scan

A magnetic resonance imaging (MRI) scan produces detailed pictures of internal organs, including the heart and brain. Patients lie in a short tunnel-like machine which contains a cylindrical magnet. Short bursts of magnetic fields and radio waves create images of parts of the body as required.
MRI can measure the flow of blood through some of the major arteries and can detect abnormal heart function in disorders such as cardiomyopathy (heart muscle disease), coronary heart disease, and congenital heart defects and help define the location and extent of brain injury in stroke patients.
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Nuclear imaging

A very small and harmless quantity of radioactive substance, called an isotope, is injected into the blood, often while exercising. Gamma rays emitted by the isotope - usually technetium or thallium - are picked up by a "camera" positioned close to the chest and tests the size and pumping function of the heart chambers, taking pictures of the inside of the heart as it empties and fills. Blood flow to the heart muscleis also studied, taking pictures of the flow of blood to the muscular walls of the heart.
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Thallium scan

Radioactive dye is injected during exercise to demonstrate the amount of blood reaching different parts of the heart's muscular walls.
When the results of these and other tests are available, it's possible to build a picture of what is going wrong with the heart, reach a diagnosis and consider appropriate treatment.

Disclaimer

All content within BBC Health is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. The BBC is not responsible or liable for any diagnosis made by a user based on the content of the BBC Health website. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. See our Links Policy for more information. Always consult your own GP if you're in any way concerned about your health.

http://www.bbc.co.uk/health/physical_health/conditions/in_depth/heart/investigating_index.shtml

Tests to diagnose cancer

If cancer is suspected, or even as part of a regular screening programme, you may encounter one or more of the following tests.
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X-rays

A simple x-ray can show the lungs, heart outline, collar bones and ribs, and may help diagnose lung and bronchial cancers.
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Contrast x-rays

These use barium, either as a drink or as an enema, to highlight any abnormalities in an x-ray. Contrast x-rays are used to diagnose cancer of the gullet (oesophagus), stomach, colon or rectum.
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Mammogram

This is a special soft tissue x-ray of the breast which is used to detect abnormalities. As the breast tissue has to be squashed to take the picture some women find this uncomfortable. Mammograms are used in the screening of all women, whether or not the woman displays symptoms of breast cancer.
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CT

CT, or computerized tomography, scanning gives a more detailed view of sections of the body, detecting changes in shape. CT is often used when trying to detect very small cancers in the body.
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MRI

MRI, or magnetic resonance imaging, uses a powerful magnetic field in combination with radio waves to create images similar to CT, but without exposing the patient to ionising radiation. These images give much more information than other imaging techniques, enabling a more detailed and accurate interpretation of the results. This type of imaging can be very noisy but you can listen to music to help block out the noise. Because of the magnet, patients with any implants containing metal (e.g. cardiac pacemakers, aneurysm clips, artificial heart valves, cochlea implants, implanted pumps, tattooed eyeliner) can’t have an MRI.
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Nuclear medicine

These scans can be used to look at bones, kidneys, lungs and the thyroid gland. This usually involves an injection of a small amount of radiation and you’re provided with a list of do’s and don’ts for 12 hours after the scan.
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Ultrasound imaging

Ultrasound is a non-invasive investigation of soft tissues in the body using high frequency sound waves to produce pictures of body organs.
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Cytological investigations

This test may be performed to collect cells from an abnormality within the body. A needle and syringe is used to take cells from a lump, a lymph node, thyroid gland or bone marrow. Cells from the cervix may be collected using a swab (a smear test). Taking these cells can be quite uncomfortable but is important in getting the right diagnosis.
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Endoscopy

A tube with a tiny camera and light is used to look at different parts of the body, including the gullet, lungs, stomach and bowel.
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Surgery

Sometimes it isn't possible to reach a definite diagnosis without a biopsy. This involves taking a small piece of tissue for testing and is often carried out under a local anaesthetic.
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Blood tests

Blood tests are very common and are usually done to look at how the organs in the body are working.
Some tests are done immediately by your GP, but others may take longer to arrange as they’re more complex and require hospital visits. Results may take a little time to get as scans and test reports have to be checked and double checked by experts. An appointment is usually made once all your results are available. If you think you should be having a particular test, it's important to discuss your concerns with your doctor who will be able to tell you if the test is appropriate. Often when you see your doctor you may forget some of the things you want to ask, so it's often useful to write these things down before you go.

Disclaimer

All content within BBC Health is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. The BBC is not responsible or liable for any diagnosis made by a user based on the content of the BBC Health website. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. See our Links Policy for more information. Always consult your own GP if you're in any way concerned about your health.

http://www.bbc.co.uk/health/physical_health/conditions/in_depth/cancer/carecancer_test.shtml

what is cancer

How cancer causes harm

Cancer harms the body in a number of ways. The size of the tumour, for example, can interfere with nearby organs or ducts that carry important chemicals, causing pain or other symptoms.
A tumour on the pancreas can grow to block the bile duct, leading to the patient developing obstructive jaundice. A brain tumour can push on important parts of the brain, causing blackouts, fits and other problems. Even benign tumours can cause these problems if located in the wrong place.
When a cancer invades nearby tissues, it can cause bleeding from damaged blood vessels, and stop the organ it is invading from working properly.
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How cancer spreads

As a tumour grows, cells can break off and start growing on adjacent tissues and organs. For example, if bowel cancer has spread through the wall of the bowel itself, it can start growing on the bladder. Cells can also enter the bloodstream and travel to distant organs, such as the lungs or brain. The technical term for this is metastasis.
When new tumours form on distant organs, they behave like the original tumour - so a bowel cancer cell growing in the lung will not be lung cancer.
Once other organs are involved, any symptoms of the cancer can get worse. However, it may be some time before a growing cancer in certain parts of the body produces noticeable symptoms.
Once a cancer has started to spread beyond its original site, the chances of a cure often begin to fall, as it becomes more difficult to treat.
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How cancer is treated

There are three principal ways of treating cancer.
The first is surgery, normally an operation to remove the cancerous growth and - depending on its type - nearby tissues and organs. A cancer patient may first undergo a minor operation called a biopsy to take a small sample of the cancer for analysis.
The surgeon will try to remove as much of the cancer as possible, but sometimes extra treatment will be needed. This could either take the form of radiotherapy or chemotherapy, or a combination.
While the overall number of new cancers is not falling, the good news is that successful treatment rates for many of the most common types are improving rapidly
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Support for those with cancer

All patients treated with chemotherapy will be looked after by ateam of healthcare professionals, who are there to support you and access specialist support if required.

Disclaimer

All content within BBC Health is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. The BBC is not responsible or liable for any diagnosis made by a user based on the content of the BBC Health website. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. See our Links Policy for more information. Always consult your own GP if you're in any way concerned about your health.

http://www.bbc.co.uk/health/physical_health/conditions/in_depth/cancer/whatis_cancer.shtml

Sunday 25 December 2011

The Kidneys and How They Work


What are the kidneys?

The kidneys play key roles in body function, not only by filtering the blood and getting rid of waste products, but also by balancing levels of electrolyte levels in the body, controlling blood pressure, and stimulating the production of red blood cells.
The kidneys are located in the abdomen toward the back, normally one on each side of the spine. They get their blood supply through the renal arteries directly from the aorta and send blood back to the heart via the renal veins to the vena cava. (The term "renal" is derived from the Latin name for kidney.)
The kidneys have the ability to monitor the amount of body fluid, the concentrations of electrolytes like sodium and potassium, and the acid-base balance of the body. They filter waste products of body metabolism, like urea from protein metabolism and uric acid from DNA breakdown. Two waste products in the blood can be measured: blood urea nitrogen (BUN) and creatinine (Cr).
When blood flows to the kidney, sensors within the kidney decide how much water to excrete as urine, along with what concentration of electrolytes. For example, if a person is dehydrated from exercise or from an illness, the kidneys will hold onto as much water as possible and the urine becomes very concentrated. When adequate water is present in the body, the urine is much more dilute, and the urine becomes clear. This system is controlled by renin, a hormone produced in the kidney that is part of the fluid and blood pressure regulation systems of the body.
Kidneys are also the source of erythropoietin in the body, a hormone that stimulates the bone marrow to make red blood cells. Special cells in the kidney monitor the oxygen concentration in blood. If oxygen levels fall, erythropoietin levels rise and the body starts to manufacture more red blood cells.
After the kidneys filter blood, the urine is excreted through the ureter, a thin tube that connects it to the bladder. It is then stored in the bladder awaiting urination, when the bladder sends the urine out of the body through the urethra.
Picture of the Kidneys and Urinary Structures

What causes kidney failure?

Kidney failure can occur from an acute situation or from chronic problems.
In acute renal failure, kidney function is lost rapidly and can occur from a variety of insults to the body. The list of causes is often categorized based on where the injury has occurred.
Prerenal causes (pre=before + renal=kidney) causes are due to decreased blood supply to the kidney. Examples of prerenal causes of kidney failure are:
  • hypovolemia (low blood volume) due to blood loss;
  • dehydration from loss of body fluid (for example, vomitingdiarrhea, sweating, fever);
  • poor intake of fluids;
  • medication, for example, diuretics ("water pills") may cause excessive water loss; and
  • abnormal blood flow to and from the kidney due to obstruction of the renal artery or vein.
Renal causes of kidney failure (damage directly to the kidney itself) include:
Post renal causes of kidney failure (post=after + renal= kidney) are due to factors that affect outflow of the urine:
  • Obstruction of the bladder or the ureters can cause back pressure because the kidneys continue to produce urine, but the obstruction acts like a dam, and urine backs up into the kidneys. When the pressure increases high enough, the kidneys are damaged and shut down.
  • Prostatic hypertrophy or prostate cancer may block the urethra and prevents the bladder from emptying.
  • Tumors in the abdomen that surround and obstruct the ureters.
  • Kidney stones. Usually, kidney stones affect only one kidney and do not cause kidney failure. However, if there is only one kidney present, a kidney stone may cause the lone kidney to fail.
Chronic renal failure develops over months and years. The most common causes of chronic renal failure are related to:
Less common causes of chronic renal failure include:

What are the symptoms of kidney failure?

  • In the beginning, kidney failure may be asymptomatic (not producing any symptoms). As kidney function decreases, the symptoms are related to the inability to regulate water and electrolyte balances, to clear waste products from the body, and to promote red blood cell production. Lethargy,weaknessshortness of breath, and generalized swelling may occur. Unrecognized or untreated, life-threatening circumstances can develop.
  • Metabolic acidosis, or increased acidity of the body due to the inability to manufacture bicarbonate, will alter enzyme and oxygen metabolism, causing organ failure.
  • Inability to excrete potassium and rising potassium levels in the serum (hyperkalemia) is associated with fatal heart rhythm disturbances (arrhythmias) including ventricular tachycardia and ventricular fibrillation.
  • Rising urea levels in the blood (uremia) can affect the function of a variety of organs ranging from the brain (encephalopathy) with alteration of thinking, to inflammation of the heart lining (pericarditis), to decreased muscle function because of low calcium levels (hypocalcemia).
  • Generalized weakness may be due to anemia, a decreased red blood cell count, because lower levels of erythropoietin produced by failing kidneys do not adequately stimulate the bone marrow. A decrease in red cells equals a decrease in oxygen-carrying capacity of the blood, resulting in decreased oxygen delivery to cells for them to do work; therefore, the body tires quickly. As well, with less oxygen, cells more readily use anaerobic metabolism (an=without + aerobic=oxygen) leading to increased amounts of acid production that cannot be addressed by the already failing kidneys.
  • As waste products build in the blood, loss of appetite, lethargy, and fatigue become apparent. This will progress to the point where mental function will decrease and coma may occur.
  • Because the kidneys cannot address the rising acid load in the body, breathing becomes more rapid as the lungs try to buffer the acidity by blowing off carbon dioxide. Blood pressure may rise because of the excess fluid, and this fluid can be deposited in the lungs, causingcongestive heart failure.

How is kidney failure diagnosed?

Diagnosis of kidney failure is confirmed by blood tests measuring the buildup of waste products in the blood. BUN, creatinine, and GFR are routine blood tests used to measure the buildup of waste products in the blood. BUN and creatinine become elevated, and the glomerular filtration rate (GFR) decreases. This is the rate with which blood is filtered through the kidneys and can be calculated based upon the creatinine level, age, race, and gender.
Urine tests may be done to measure the amount of protein, detect the presence of abnormal cells, or measure the concentration of electrolytes. Protein in the urine is not normal and can be a clue that damage to the kidneys has occurred. Abnormal aggregations of red and white blood cells called casts can be seen in the urine with kidney disease. Comparing the concentrations of electrolytes in the blood and urine can help decide whether the kidneys are able to appropriately monitor and filter blood.
Other tests are used to diagnose the type of kidney failure. Abdominal ultrasound can assess the size of the kidneys and may identify whether any obstruction exists. Biopsy of the kidney uses a thin needle that is placed through the skin into the kidney itself to get bits of tissue to examine under the microscope.

What is the treatment for kidney failure?

Prevention is always the goal with kidney failure. Chronic diseases such ashypertension and diabetes are devastating because of the damage that they can do to kidneys and other organs. Lifelong diligence is important in keeping blood sugar and blood pressure within normal limits. Specific treatments are dependent upon the underlying diseases.
Once kidney failure is present, the goal is to prevent further deterioration of renal function. If ignored, the kidneys will progress to complete failure, but if underlying illnesses are addressed and treated aggressively, kidney function can be preserved, though not always improved.

Diet

Diet is an important consideration for those with impaired kidney function. Consultation with a dietician may be helpful to understand what foods may or may not be appropriate.
Since the kidneys cannot easily remove excess water, salt, or potassium, these may need to be consumed in limited quantities. Foods high in potassium include bananas, apricots, and salt substitutes.
Phosphorus is a forgotten chemical that is associated with calcium metabolism and may be elevated in the body in kidney failure. Too much phosphorus can leech calcium from the bones and cause osteoporosis and fractures. Foods with high phosphorus content include milk, cheese, nuts, and cola drinks.

Medications

Medications may be used to help control some of the issues associated with kidney failure.
Once the kidneys fail completely, the treatment options are limited to dialysis or kidney replacement by transplantation.

Dialysis

Dialysis cleanses the body of waste products in the body by use of filter systems. There are two types of dialysis; 1) hemodialysis, and 2) peritoneal dialysis.

Hemodialysis

Hemodialysis uses a machine filter called a dialyzer or artificial kidney to remove excess water and salt, to balance the other electrolytes in the body, and to remove waste products of metabolism. Blood is removed from the body and flows through tubing into the machine, where it passes next to a filter membrane. A specialized chemical solution (dialysate) flows on the other side of the membrane. The dialysate is formulated to draw impurities from the blood through the filter membrane. Blood and dialysate never touch in the artificial kidney machine.
For this type of dialysis, access to the blood vessels needs to be surgically created so that large amounts of blood can flow into the machine and back to the body. Surgeons can build a fistula, a connection between a large artery and vein in the body, usually in the arm, that causes a large amount of blood flow into the vein. This makes the vein larger and its walls thicker so that it can tolerate repeated needle sticks to attach tubing from the body to the machine. Since it takes many weeks for a fistula to mature enough to be used, significant planning is required if hemodialysis is to be considered as an option.
If the kidney failure happens acutely and there is no time to build a fistula, special catheters may be inserted into the larger blood vessels of the arm, leg, or chest. These catheters may be left in place for up to three weeks. In some diseases, the need for dialysis will be temporary, but if the expectation is that dialysis will continue for a prolonged period of time, these catheters act as a bridge until a fistula can be planned, placed, and matured.
Dialysis treatments normally occur three times a week and last a few hours at a time. Most commonly, patients travel to an outpatient center to have dialysis, but home dialysis therapy is becoming an option for some.

Peritoneal dialysis

Peritoneal dialysis uses the lining of the abdominal cavity as the dialysis filter to rid the body of waste and to balance electrolyte levels. A catheter is placed in the abdominal cavity through the abdominal wall by a surgeon and is expected to remain there for the long-term. The dialysis solution is then dripped in through the catheter and left in the abdominal cavity for a few hours and then is drained out. In that time, waste products leech from the blood normally flowing through the lining of the abdomen (peritoneum).
There are benefits and complications for each type of dialysis. Not every patient can choose which type he or she would prefer. The treatment decision depends on the patient's illness and their past medical history along with other issues. Usually, the nephrologist (kidney specialist) will have a long discussion with the patient and family to decide what will be the best option available.
Dialysis is life saving. Without it, patients whose kidneys no longer function would die relatively quickly due to electrolyte abnormalities and the buildup of toxins in the blood stream. Patients may live many years with dialysis but other underlying and associated illnesses often are the cause of death.

Kidney transplantation

If kidney failure occurs and is non-reversible, kidney transplantation is an alternative option to dialysis. If the patient is an appropriate candidate, the health care practitioner will contact an organ transplant center to arrange evaluation to see if the patient is suitable for this treatment. If so, the search for a donor begins. Sometimes, family members have compatible tissue types and, if they are willing, may donate a kidney. Otherwise, the patient will be placed on the organ transplant list that is maintained by the United Network of Organ Sharing.
Not all hospitals are capable of performing kidney transplants. The patient may have to travel to undergo their operation. The most successful programs are those that do many transplants every year.
While kidney transplants have become more routine, they still carry some risk. The patient will need to take anti-rejection medications that reduce the ability of the immune system to fight infection. The body can try to reject the kidney or the transplanted kidney may fail to work. As with any operation, there is a risk of bleeding and infection.
Kidney transplants may provide better quality of life than dialysis. After one year, 95% of transplanted kidneys are still functioning and after five years the number is 80%. It seems that the longer a patient is on dialysis, the shorter the life of the transplanted kidney.
If the transplanted kidney fails, the alternative is another kidney transplant or a return to dialysis.

What is the prognosis for someone with kidney failure?

The outlook for kidney failure depends upon the underlying condition that caused it. Kidney function may return to normal, especially if it is due to an acute obstruction and that obstruction is relieved. Other causes of decreased kidney function leading to kidney failure are due to underlying disease and occur slowly over time.
Prevention is the best chance to maintain kidney function, and controlling high blood pressure and diabetes over a lifetime can decrease the potential for progressive kidney damage. Chronic kidney failure may be managed by a primary health care practitioner or a nephrologist to help monitor electrolyte and waste product levels in the bloodstream. Major abnormalities can be life-threatening, and treatment options may be limited to dialysis or transplant.
Kidney Failure At A Glance
  • Kidneys are the organs that help filter waste products from the blood. They are also involved in regulating blood pressure, electrolyte balance, and red blood cell production in the body.
  • There are numerous causes of kidney failure, and treatment of the underlying disease may be the first step in correcting the kidney abnormality.
  • Some causes of kidney failure are treatable and the kidney function may return to normal. Unfortunately, kidney failure may be progressive in other situations and may be irreversible.
  • Symptoms of kidney failure are due to the build-up of waste products in the body that may cause weaknessshortness of breath, lethargy, andconfusion. Inability to remove potassium from the bloodstream may lead to abnormal heart rhythms and sudden death. Initially, there may be no symptoms of kidney failure.
  • The diagnosis of kidney failure usually is made by blood tests measuring BUN, creatinine, and glomerular filtration rate (GFR).
  • Treatment of the underlying cause of kidney failure may return kidney function to normal. Lifelong efforts to control blood pressure and diabetes may be the best way to prevent chronic kidney disease and its progression to kidney failure. Usually, kidney function gradually decreases over time.
  • If the kidneys fail completely, the only treatment options available may be dialysis or transplant.

REFERENCE: eMedicine.com. Renal Failure, Acute.
<http://emedicine.medscape.com/article/777845-overview>