Hypertension
Encyclopedia
Hypertension or high blood pressure is a cardiac chronic
medical condition
in which the systemic arterial blood pressure
is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and diastolic. Normal blood pressure is 120/80 mm/Hg. The first figure is the systolic blood pressure, the pressure there is in the arteries when your heart is contracting. The second, or lower figure, is the diastolic blood pressure, which is the pressure in your arteries between heart beats. High blood pressure is anything above 140/90 mm/Hg.
Hypertension is the opposite of hypotension
. Hypertension is classified as either primary (essential) hypertension or secondary hypertension; about 90–95% of cases are categorized as "primary hypertension," which means high blood pressure with no obvious medical cause. The remaining 5–10% of cases (Secondary hypertension
) are caused by other conditions that affect the kidneys, arteries, heart or endocrine system.
Persistent hypertension is one of the risk factors
for stroke
, myocardial infarction
, heart failure and arterial aneurysm
, and is a leading cause of chronic kidney failure. Moderate elevation of arterial blood pressure leads to shortened life expectancy
. Dietary and lifestyle changes can improve blood pressure control and decrease the risk of associated health complications, although drug treatment may prove necessary in patients for whom lifestyle changes prove ineffective or insufficient.
Blood pressure is usually classified based on the systolic and diastolic blood pressures. Systolic blood pressure is the blood pressure in vessels during a heart beat. Diastolic blood pressure is the pressure between heartbeats. A systolic or the diastolic blood pressure measurement higher than the accepted normal values for the age of the individual is classified as prehypertension or hypertension.
Hypertension has several sub-classifications, including hypertension stage I, hypertension stage II, and isolated systolic hypertension. Isolated systolic hypertension refers to elevated systolic pressure with normal diastolic pressure and is common in the elderly. These classifications are made after averaging a patient's resting blood pressure readings taken on two or more office visits. Individuals older than 50 years are classified as having hypertension if their blood pressure is consistently at least 140 mmHg systolic or 90 mmHg diastolic. Patients with blood pressures higher than 130/80 mmHg with concomitant presence of diabetes mellitus
or kidney disease require further treatment.
Hypertension is also classified as resistant if medications do not reduce blood pressure to normal levels.
Exercise hypertension
is an excessively high elevation in blood pressure during exercise. The range considered normal for systolic values during exercise is between 200 and 230 mm Hg. Exercise hypertension may indicate that an individual is at risk for developing hypertension at rest.
, drowsiness
, confusion
, vision disorder
s, nausea
, and vomiting
. These symptoms are collectively called hypertensive encephalopathy
. Hypertensive encephalopathy is caused by severe small blood vessel
congestion and brain swelling
, which is reversible if blood pressure is lowered.
'), wide purple marks on the abdomen (abdominal striae), or the recent onset of diabetes suggests that an individual has a hormone disorder known as Cushing's syndrome
. Hypertension caused by other hormone disorders
such as hyperthyroidism
, hypothyroidism
, or growth hormone excess will be accompanied by additional symptoms specific to these disorders. For example, hyperthyrodism can cause weight loss
, tremors, heart rate abnormalities
, reddening of the palms
, and increased sweating
. Signs and symptoms associated with growth hormone excess include coarsening of facial features, protrusion of the lower jaw
, enlargement of the tongue
, excessive hair growth
, darkening of the skin color
, and excessive sweating
.. Other hormone disorders like hyperaldosteronism
may cause less specific symptoms such as numbness, excessive urination
, excessive sweating
, electrolyte imbalances and dehydration, and elevated blood alkalinity
. and also cause mental pressure.
. Pre-eclampsia can progress to a life-threatening condition called eclampsia
, which is the development of protein in the urine
, generalized swelling
, and severe seizures. Other symptoms indicating that brain function is becoming impaired may precede these seizures such as nausea, vomiting, headaches, and vision loss
.
In addition, the systemic vascular resistance and blood pressure decrease during pregnancy. The body must compensate by increasing cardiac output and blood volume to provide sufficient circulation in the utero-placental arterial bed.
, seizures, irritability
, lack of energy, and difficulty breathing
. In children, hypertension can cause headache, fatigue, blurred vision
, nosebleeds, and facial paralysis.
Even with the above clinical symptoms, the true incidence of pediatric hypertension is not known. In adults, hypertension has been defined due to the adverse effects caused by hypertension. However, in children, similar studies have not been performed thoroughly to link any adverse effects with the increase in blood pressure. Therefore, the prevalence of pediatric hypertension remains unknown due to the lack of scientific knowledge.
, smoking, stress, visceral obesity, potassium deficiency (hypokalemia
), obesity
(more than 85% of cases occur in those with a body mass index
greater than 25), salt (sodium) sensitivity, alcohol
intake, and vitamin D deficiency
that increase the risk of developing hypertension. Risk also increases with aging, some inherited genetic mutations, and having a family history of hypertension. An elevated level of renin
, a hormone secreted by the kidney, is another risk factor, as is sympathetic nervous system overactivity. Insulin resistance
, which is a component of syndrome X
(or the metabolic syndrome
), is also thought to contribute to hypertension. Recent studies have implicated low birth weight
as a risk factor for adult essential hypertension.
, which is a condition where the adrenal gland
s overproduce the hormone cortisol
. Hypertension is also caused by other conditions that cause hormone changes, such as hyperthyroidism, hypothyroidism, and certain tumors of the adrenal medulla (e.g., pheochromocytoma
). Other common causes of secondary hypertension include kidney disease, obesity/metabolic disorder, pre-eclampsia
during pregnancy, the congenital defect known as coarctation of the aorta, and certain prescription and illegal drugs.
Most of the mechanisms associated with secondary hypertension are generally fully understood. However, those associated with essential (primary) hypertension are far less understood. What is known is that cardiac output
is raised early in the disease course, with total peripheral resistance
(TPR) normal; over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:
It is also known that hypertension is highly heritable and polygenic (caused by more than one gene) and a few candidate genes
have been postulated in the etiology of this condition.
Recently, work related to the association between essential hypertension and sustained endothelial damage has gained popularity among hypertension scientists. It remains unclear, however, whether endothelial changes precede the development of hypertension or whether such changes are mainly due to longstanding elevated blood pressures.
and physical examination
. Exceptionally, if the elevation is extreme, or if symptoms of organ damage are present, then a diagnosis may be made and treatment started immediately.
Once the diagnosis of hypertension has been made, physicians will attempt to identify the underlying cause based on risk factors and other symptoms, if present. Secondary hypertension
is more common in preadolescent children, with most cases caused by renal disease. Primary or essential hypertension
is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension. Laboratory tests can also be performed to identify possible causes of secondary hypertension, and to determine whether hypertension has caused damage to the heart
, eyes, and kidney
s. Additional tests for diabetes and high cholesterol
levels are usually performed because these conditions are additional risk factors for the development of heart disease
and require treatment. Typical tests are classified as follows:
Creatinine
(renal function
) testing is done to assess the presence of kidney disease, which can be either the cause or the result of hypertension. In addition, creatinine testing provides a baseline measurement of kidney function that can be used to monitor for side effects of certain antihypertensive drugs on kidney function. Additionally, testing of urine samples for protein
is used as a secondary indicator of kidney disease. Glucose
testing is done to determine if diabetes mellitus is present. Electrocardiogram
(EKG/ECG) testing is done to check for evidence that the heart is under strain from high blood pressure. It may also show whether there is thickening of the heart muscle (left ventricular hypertrophy
) or whether the heart has experienced a prior minor disturbance such as a silent heart attack. A chest X-ray
may be performed to look for signs of heart enlargement or damage to heart tissue.
, kidney
, heart, among others), risk factors for cardiovascular diseases and the age at diagnosis of prehypertension or at risk for hypertension. A prolonged assessment that involves repeated blood pressure measurements provides the most accurate blood pressure level assessment. Following this, lifestyle changes are recommended to lower blood pressure, before the initiation of prescription drug therapy. According to the British Hypertension Society, the process of managing prehypertension includes lifestyle changes such as the following:
These have all been shown to significantly reduce blood pressure in people with hypertension. If hypertension is high enough to justify immediate use of medications, lifestyle changes are still recommended in conjunction with medication. Drug prescription should take into account the patient's absolute cardiovascular risk (including risk of myocardial infarction and stroke) as well as blood pressure readings, in order to gain a more accurate picture of the patient's cardiovascular profile. Different programs aimed to reduce psychological stress such as biofeedback
, relaxation
or meditation
are advertised to reduce hypertension. However, in general claims of efficacy are not supported by scientific studies, which have been in general of low quality.
Regarding dietary changes, a low sodium diet
is beneficial. A Cochrane review published in 2008 concluded that a long term (more than 4 weeks) low sodium diet in Caucasians
is effective in reducing blood pressure, both in people with hypertension and in people with normal blood pressure. Also, the DASH diet (Dietary Approaches to Stop Hypertension) is a diet
promoted by the National Heart, Lung, and Blood Institute
(part of the NIH, a United States government organization) to control hypertension. A major feature of the plan is limiting intake of sodium
, and it also generally encourages the consumption of nuts, whole grains, fish, poultry, fruits and vegetables while lowering the consumption of red meats, sweets, and sugar. It is also "rich in potassium
, magnesium
, and calcium
, as well as protein
".
by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease
by 21%, and reduce the likelihood of dementia
, heart failure, and mortality
from cardiovascular disease
. The aim of treatment should be to reduce blood pressure to <140/90 mmHg for most individuals, and lower for individuals with diabetes or kidney disease (some medical professionals recommend keeping levels below 120/80 mmHg). If the blood pressure goal is not met, a change in treatment should be made as therapeutic inertia
is a clear impediment to blood pressure control. Comorbidity also plays a role in determining target blood pressure, with lower BP targets applying to patients with end-organ damage or proteinuria.
The first line antihypertensive supported by the best evidence is a low dose thiazide-based diuretic
.
Often multiple medications are needed to be combined to achieve the goal blood pressure. Commonly used prescription drugs include:
ACE inhibitor
s, alpha blocker
s, angiotensin II receptor antagonist
s, beta blocker
s, calcium channel blocker
s, diuretics (e.g. hydrochlorothiazide
), direct renin inhibitor
s and Glyceryl trinitrates which has the activity of vasodilation
, thus controlling high blood pressure
.
Some examples of common combined prescription drug include:
Combinations of an ACE-inhibitor or angiotensin II–receptor antagonist, a diuretic and an NSAID (including selective COX-2 inhibitors and non-prescribed drugs such as ibuprofen) should be avoided whenever possible due to a high documented risk of acute renal failure. The combination is known colloquially as a "triple whammy" in the Australian health industry.
Hypertension is the most important risk factor for death in industrialized countries. It increases hardening of the arteries
thus predisposes individuals to heart disease, peripheral vascular disease, and strokes.
Types of heart disease that may occur include: myocardial infarction, heart failure, and left ventricular hypertrophy
Other complications include:
In 1995 it is estimated that 43 million people in the United States had hypertension or were taking antihypertensive medication, almost 24% of the adult population. The prevalence of hypertension in the United States is increasing and reached 29% in 2004. It is more common in blacks and native Americans and less in whites and Mexican American
s, rates increase with age, and is greater in the southeastern United States
. Hypertension is more prevalent in men (though menopause tends to decrease this difference) and those of low socioeconomic status
.
Over 90–95% of adult hypertension is essential hypertension
. One of the most common causes of secondary hypertension is primary aldosteronism. The incidence
of exercise hypertension is reported to range from 1–10%.
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Some cite the writings of Sushruta in the 6th century BC as being the first mention of symptoms like those of hypertension. Others propose even earlier descriptions dating as far as 2600 BCE. Main treatment for what was called the "hard pulse disease" consisted in reducing the quantity of blood in a subject by the sectioning of veins or the application of leech
es. Well known individuals such as The Yellow Emperor
of China, Cornelius Celsus
, Galen
, and Hipocrates advocated such treatments.
Our modern understanding of hypertension began with the work of physician William Harvey
(1578–1657), who was the first to describe correctly the systemic circulation of blood being pumped around the body by the heart in his book "De motu cordis". The basis for measuring blood pressure were established by Stephen Hales
in 1733. Initial descriptions of hypertension as a disease came among others from Thomas Young
in 1808 and specially Richard Bright
in 1836. The first ever elevated blood pressure in a patient without kidney disease was reported by Frederick Mahomed (1849–1884). It was not until 1904 that sodium restriction was advocated while a rice diet was popularized around 1940.
Studies in the 1920s demonstrated the public health
impact of untreated high blood pressure; treatment options were limited at the time, and deaths from malignant hypertension
and its complications were common. A prominent victim of severe hypertension leading to cerebral hemorrhage was Franklin D. Roosevelt
(1882–1945). The Framingham Heart Study
added to the epidemiological understanding of hypertension and its relationship with coronary artery disease. The National Institutes of Health
also sponsored other population studies, which additionally showed that African Americans had a higher burden of hypertension and its complications. Before pharmacological treatment for hypertension became possible, three treatment modalities were used, all with numerous side-effects: strict sodium restriction, sympathectomy
(surgical ablation of parts of the sympathetic nervous system
), and pyrogen therapy (injection of substances that caused a fever, indirectly reducing blood pressure).
The first chemical for hypertension, sodium thiocyanate
, was used in 1900 but had many side effects and was unpopular. Several other agents were developed after the Second World War
, the most popular and reasonably effective of which were tetramethylammonium chloride
and its derivative hexamethonium
, hydralazine
and reserpine
(derived from the medicinal plant Rauwolfia serpentina
). A randomized controlled trial
sponsored by the Veterans Administration
using these drugs had to be stopped early because those not receiving treatment were developing more complications and it was deemed unethical to withhold treatment from them. These studies prompted public health campaigns to increase public awareness of hypertension and the advice to get blood pressure measured and treated. These measures appear to have contributed at least in part of the observed 50% fall in stroke and ischemic heart disease between 1972 and 1994.
A major breakthrough was achieved with the discovery of the first well-tolerated orally available agents. The first was chlorothiazide
, the first thiazide
and developed from the antibiotic sulfanilamide, which became available in 1958; it increased salt excretion while preventing fluid accumulation. In 1975, the Lasker Special Public Health Award
was awarded to the team that developed chlorothiazide. The British physician James W. Black
developed beta blocker
s in the early 1960s; these were initially used for angina, but turned out to lower blood pressure. Black received the 1976 Lasker Award and in 1988 the Nobel Prize in Physiology or Medicine
for his discovery. The next class of antihypertensives to be discovered was that of the calcium channel blockers. The first member was verapamil
, a derivative of papaverine
that was initially thought to be a beta blocker and used for angina, but then turned out to have a different mode of action and was shown to lower blood pressure. ACE inhibitors were developed through rational drug design
; the renin-angiotensin system was known to play an important role in blood pressure regulation, and snake venom from Bothrops jararaca
could lower blood pressure through inhibition of ACE. In 1977 captopril
, an orally active agent, was described; this led to the development of a number of other ACE inhibitors.
High blood pressure is the most common chronic medical problem prompting visits to primary health care providers, yet it is estimated that only 34% of the 50 million American adults with hypertension have their blood pressure controlled to a level of <140/90 mm Hg. Thus, about two thirds of Americans with hypertension are at increased risk for heart disease. The medical, economic, and human costs of untreated and inadequately controlled high blood pressure are enormous. Adequate management of hypertension can be hampered by inadequacies in the diagnosis, treatment, and/or control of high blood pressure. Health care providers face many obstacles to achieving blood pressure control from their patients, including resistance to taking multiple medications to reach blood pressure goals. Patients also face the challenges of adhering to medicine schedules and making lifestyle changes. Nonetheless, the achievement of blood pressure goals is possible, and most importantly, lowering blood pressure significantly reduces the risk of death due to heart disease, the development of other debilitating conditions, and the cost associated with advanced medical care.,
The World Health Organization attributes hypertension, or high blood pressure, as the leading cause of cardiovascular mortality
. The World Hypertension League (WHL), an umbrella organization of 85 national hypertension societies and leagues, recognized that more than 50% of the hypertensive population worldwide are unaware of their condition. To address this problem, the WHL initiated a global awareness campaign on hypertension in 2005 and dedicated May 17 of each year as World Hypertension Day
(WHD
). Over the past three years, more national societies have been engaging in WHD and have been innovative in their activities to get the message to the public. In 2007, there was record participation from 47 member countries of the WHL. During the week of WHD, all these countries – in partnership with their local governments, professional societies, nongovernmental organizations and private industries – promoted hypertension awareness among the public through several media
and public rallies. Using mass media
such as Internet
and television
, the message reached more than 250 million people. As the momentum picks up year after year, the WHL is confident that almost all the estimated 1.5 billion people affected by elevated blood pressure can be reached.
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
medical condition
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
in which the systemic arterial blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and diastolic. Normal blood pressure is 120/80 mm/Hg. The first figure is the systolic blood pressure, the pressure there is in the arteries when your heart is contracting. The second, or lower figure, is the diastolic blood pressure, which is the pressure in your arteries between heart beats. High blood pressure is anything above 140/90 mm/Hg.
Hypertension is the opposite of hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
. Hypertension is classified as either primary (essential) hypertension or secondary hypertension; about 90–95% of cases are categorized as "primary hypertension," which means high blood pressure with no obvious medical cause. The remaining 5–10% of cases (Secondary hypertension
Secondary hypertension
Secondary hypertension is a type of hypertension which by definition is caused by an identifiable underlying secondary cause. It is much less common than the other type, called essential hypertension, affecting only 5% of hypertensive patients. It has many different causes including endocrine...
) are caused by other conditions that affect the kidneys, arteries, heart or endocrine system.
Persistent hypertension is one of the risk factors
Risk factors
A risk factor is a concept in finance theory such as the CAPM, APT and other theories that use pricing kernels. In these models, the rate of return of an asset is a random variable whose realization in any time period is a linear combination of other random variables plus a disturbance term or...
for stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
, heart failure and arterial aneurysm
Aneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...
, and is a leading cause of chronic kidney failure. Moderate elevation of arterial blood pressure leads to shortened life expectancy
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...
. Dietary and lifestyle changes can improve blood pressure control and decrease the risk of associated health complications, although drug treatment may prove necessary in patients for whom lifestyle changes prove ineffective or insufficient.
Classification
| Classification | Systolic pressure | Diastolic pressure | ||
|---|---|---|---|---|
| mmHg | kPa Pascal (unit) The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre... |
mmHg | kPa | |
| Normal | 90–119 | 12–15.9 | 60–79 | 8.0–10.5 |
| Prehypertension | 120–139 | 16.0–18.5 | 80–89 | 10.7–11.9 |
| Stage 1 | 140–159 | 18.7–21.2 | 90–99 | 12.0–13.2 |
| Stage 2 | ≥160 | ≥21.3 | ≥100 | ≥13.3 |
| Isolated systolic hypertension |
≥140 | ≥18.7 | <90 | <12.0 |
| Source: American Heart Association (2003). | ||||
Blood pressure is usually classified based on the systolic and diastolic blood pressures. Systolic blood pressure is the blood pressure in vessels during a heart beat. Diastolic blood pressure is the pressure between heartbeats. A systolic or the diastolic blood pressure measurement higher than the accepted normal values for the age of the individual is classified as prehypertension or hypertension.
Hypertension has several sub-classifications, including hypertension stage I, hypertension stage II, and isolated systolic hypertension. Isolated systolic hypertension refers to elevated systolic pressure with normal diastolic pressure and is common in the elderly. These classifications are made after averaging a patient's resting blood pressure readings taken on two or more office visits. Individuals older than 50 years are classified as having hypertension if their blood pressure is consistently at least 140 mmHg systolic or 90 mmHg diastolic. Patients with blood pressures higher than 130/80 mmHg with concomitant presence of diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
or kidney disease require further treatment.
Hypertension is also classified as resistant if medications do not reduce blood pressure to normal levels.
Exercise hypertension
Exercise hypertension
Exercise hypertension is an excessive rise in blood pressure during exercise. Many of those with exercise hypertension have spikes in systolic pressure to 250 mmHg or greater....
is an excessively high elevation in blood pressure during exercise. The range considered normal for systolic values during exercise is between 200 and 230 mm Hg. Exercise hypertension may indicate that an individual is at risk for developing hypertension at rest.
Accelerated hypertension
Accelerated hypertension is associated with headacheHeadache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...
, drowsiness
Somnolence
Somnolence is a state of near-sleep, a strong desire for sleep, or sleeping for unusually long periods . It has two distinct meanings, referring both to the usual state preceding falling asleep, and the chronic condition referring to being in that state independent of a circadian rhythm...
, confusion
ConFusion
ConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association. Commonly, it is held the third weekend of January. It is the oldest science fiction convention in Michigan, a regional, general SF con...
, vision disorder
Vision disorder
A vision disorder is an impairment of the sense of vision.It is not the same as an eye disease. Although many vision disorders are due have their immediate cause in the eye, there are many other causes that may occur at other locations in the optic pathway...
s, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, and vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
. These symptoms are collectively called hypertensive encephalopathy
Hypertensive encephalopathy
Hypertensive encephalopathy is a neurological dysfunction induced by malignant hypertension. The term "hypertensive encephalopathy" was introduced to describe this type of encephalopathy by Oppenheimer and Fishberg in 1928. It describes cerebral conditions, typically reversible, caused by sudden...
. Hypertensive encephalopathy is caused by severe small blood vessel
Capillary
Capillaries are the smallest of a body's blood vessels and are parts of the microcirculation. They are only 1 cell thick. These microvessels, measuring 5-10 μm in diameter, connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste...
congestion and brain swelling
Cerebral edema
Cerebral edema or cerebral œdema is an excess accumulation of water in the intracellular or extracellular spaces of the brain.-Vasogenic:Due to a breakdown of tight endothelial junctions which make up the blood-brain barrier...
, which is reversible if blood pressure is lowered.
Secondary hypertension
Some additional signs and symptoms suggest that the hypertension is caused by disorders in hormone regulation. Hypertension combined with obesity distributed on the trunk of the body, accumulated fat on the back of the neck ('buffalo humpLipodystrophy
Lipodystrophy is a medical condition characterized by abnormal or degenerative conditions of the body's adipose tissue. A more specific term, lipoatrophy is used when describing the loss of fat from one area...
'), wide purple marks on the abdomen (abdominal striae), or the recent onset of diabetes suggests that an individual has a hormone disorder known as Cushing's syndrome
Cushing's syndrome
Cushing's syndrome is a hormone disorder caused by high levels of cortisol in the blood. This can be caused by taking glucocorticoid drugs, or by tumors that produce cortisol or adrenocorticotropic hormone or CRH...
. Hypertension caused by other hormone disorders
Endocrine disease
Endocrine diseases are disorders of the endocrine system. The branch of medicine associated with endocrine disorders is known as endocrinology.-Types of endocrine disease:Broadly speaking, endocrine disorders may be subdivided into three groups:...
such as hyperthyroidism
Hyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
, hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, or growth hormone excess will be accompanied by additional symptoms specific to these disorders. For example, hyperthyrodism can cause weight loss
Weight loss
Weight loss, in the context of medicine, health or physical fitness, is a reduction of the total body mass, due to a mean loss of fluid, body fat or adipose tissue and/or lean mass, namely bone mineral deposits, muscle, tendon and other connective tissue...
, tremors, heart rate abnormalities
Tachycardia
Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
, reddening of the palms
Palmar erythema
Palmar erythema is reddening of the palms at the thenar and hypothenar eminences.-Causes:It is associated with various physiological as well as pathological changes, the principal one of which is portal hypertension. It is also seen in patients with liver dysfunction, such as chronic liver disease...
, and increased sweating
Sweating
Perspiration is the production of a fluid consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...
. Signs and symptoms associated with growth hormone excess include coarsening of facial features, protrusion of the lower jaw
Prognathism
Prognathism is a term used to describe the positional relationship of the mandible and/or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In general dentistry, oral and maxillofacial surgery and orthodontics...
, enlargement of the tongue
Macroglossia
Macroglossia is the medical term for unusual enlargement of the tongue. Severe enlargement of the tongue can cause cosmetic and functional difficulties including in speaking, eating, swallowing and sleeping.- Amyloid Disorders :...
, excessive hair growth
Hypertrichosis
Hypertrichosis is an abnormal amount of hair growth on the body; extensive cases of hypertrichosis have informally been called werewolf syndrome. There are two distinct types of hypertrichosis: generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, which is...
, darkening of the skin color
Hyperpigmentation
In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.-Causes:Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris...
, and excessive sweating
Hyperhidrosis
Hyperhidrosis is the condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature.-Classification:Hyperhidrosis can either be generalized or localized to specific parts of the body...
.. Other hormone disorders like hyperaldosteronism
Hyperaldosteronism
Hyperaldosteronism, also aldosteronism, is a medical condition where too much aldosterone is produced by the adrenal glands, which can lead to lowered levels of potassium in the blood.-Types:...
may cause less specific symptoms such as numbness, excessive urination
Polyuria
Polyuria is a condition usually defined as excessive or abnormally large production or passage of urine . Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom...
, excessive sweating
Polydipsia
Polydipsia is a medical symptom in which the patient displays excessive thirst. The word derives from the Greek πολυδιψία, which is derived from πολύς + δίψα...
, electrolyte imbalances and dehydration, and elevated blood alkalinity
Metabolic alkalosis
Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range . This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations.-Terminology:*Alkalosis...
. and also cause mental pressure.
In pregnancy
Hypertension in pregnant women is one symptom of pre-eclampsiaPre-eclampsia
Pre-eclampsia or preeclampsia is a medical condition in which hypertension arises in pregnancy in association with significant amounts of protein in the urine....
. Pre-eclampsia can progress to a life-threatening condition called eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-eclampsia...
, which is the development of protein in the urine
Proteinuria
Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...
, generalized swelling
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
, and severe seizures. Other symptoms indicating that brain function is becoming impaired may precede these seizures such as nausea, vomiting, headaches, and vision loss
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
.
In addition, the systemic vascular resistance and blood pressure decrease during pregnancy. The body must compensate by increasing cardiac output and blood volume to provide sufficient circulation in the utero-placental arterial bed.
In children
Some signs and symptoms are especially important in newborns and infants such as failure to thriveFailure to thrive
Failure to thrive is a medical term which is used in both pediatric and adult human medicine, as well as veterinary medicine ....
, seizures, irritability
Irritability
Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
, lack of energy, and difficulty breathing
Infant respiratory distress syndrome
Infant respiratory distress syndrome , also called neonatal respiratory distress syndrome or respiratory distress syndrome of newborn, previously called hyaline membrane disease, is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural...
. In children, hypertension can cause headache, fatigue, blurred vision
Blurred vision
-Causes:There are many causes of blurred vision:* Use of atropine or other anticholinergics* Presbyopia -- Difficulty focusing on objects that are close. The elderly are common victims....
, nosebleeds, and facial paralysis.
Even with the above clinical symptoms, the true incidence of pediatric hypertension is not known. In adults, hypertension has been defined due to the adverse effects caused by hypertension. However, in children, similar studies have not been performed thoroughly to link any adverse effects with the increase in blood pressure. Therefore, the prevalence of pediatric hypertension remains unknown due to the lack of scientific knowledge.
Essential hypertension
Essential hypertension is the most prevalent hypertension type, affecting 90–95% of hypertensive patients. Although no direct cause has been identified, there are many factors such as sedentary lifestyleSedentary lifestyle
Sedentary lifestyle is a medical term used to denote a type of lifestyle with no or irregular physical activity. A person who lives a sedentary lifestyle may colloquially be known as a couch potato. It is commonly found in both the developed and developing world...
, smoking, stress, visceral obesity, potassium deficiency (hypokalemia
Hypokalemia
Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...
), obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
(more than 85% of cases occur in those with a body mass index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
greater than 25), salt (sodium) sensitivity, alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
intake, and vitamin D deficiency
Hypovitaminosis D
Hypovitaminosis D is a deficiency of Vitamin D. It can result from: inadequate nutritional intake of vitamin D coupled with inadequate sunlight exposure , disorders that limit vitamin D absorption, and conditions that impair the conversion of vitamin D into active metabolites including certain...
that increase the risk of developing hypertension. Risk also increases with aging, some inherited genetic mutations, and having a family history of hypertension. An elevated level of renin
Renin
Renin , also known as an angiotensinogenase, is an enzyme that participates in the body's renin-angiotensin system -- also known as the Renin-Angiotensin-Aldosterone Axis -- that mediates extracellular volume , and arterial vasoconstriction...
, a hormone secreted by the kidney, is another risk factor, as is sympathetic nervous system overactivity. Insulin resistance
Insulin resistance
Insulin resistance is a physiological condition where the natural hormone insulin becomes less effective at lowering blood sugars. The resulting increase in blood glucose may raise levels outside the normal range and cause adverse health effects, depending on dietary conditions. Certain cell types...
, which is a component of syndrome X
Metabolic syndrome
Metabolic syndrome is a combination of medical disorders that, when occurring together, increase the risk of developing cardiovascular disease and diabetes. It affects one in five people in the United States and prevalence increases with age...
(or the metabolic syndrome
Metabolic syndrome
Metabolic syndrome is a combination of medical disorders that, when occurring together, increase the risk of developing cardiovascular disease and diabetes. It affects one in five people in the United States and prevalence increases with age...
), is also thought to contribute to hypertension. Recent studies have implicated low birth weight
Low birth weight
Low birth weight is defined as a birth weight of a liveborn infant of less than 2,500 g. regardless of gestational age-Causes:LBW is either the result of preterm birth or of the infant being small for gestational age , or a combination of...
as a risk factor for adult essential hypertension.
Secondary hypertension
Secondary hypertension by definition results from an identifiable cause. This type is important to recognize since it's treated differently to essential hypertension, by treating the underlying cause of the elevated blood pressure. Hypertension results in the compromise or imbalance of the pathophysiological mechanisms, such as the hormone-regulating endocrine system, that regulate blood plasma volume and heart function. Many conditions cause hypertension. Some are common, well-recognized secondary causes such as renovascular hypertension and Cushing's syndromeCushing's syndrome
Cushing's syndrome is a hormone disorder caused by high levels of cortisol in the blood. This can be caused by taking glucocorticoid drugs, or by tumors that produce cortisol or adrenocorticotropic hormone or CRH...
, which is a condition where the adrenal gland
Adrenal gland
In mammals, the adrenal glands are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped...
s overproduce the hormone cortisol
Cortisol
Cortisol is a steroid hormone, more specifically a glucocorticoid, produced by the adrenal gland. It is released in response to stress and a low level of blood glucocorticoids. Its primary functions are to increase blood sugar through gluconeogenesis; suppress the immune system; and aid in fat,...
. Hypertension is also caused by other conditions that cause hormone changes, such as hyperthyroidism, hypothyroidism, and certain tumors of the adrenal medulla (e.g., pheochromocytoma
Pheochromocytoma
A pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
). Other common causes of secondary hypertension include kidney disease, obesity/metabolic disorder, pre-eclampsia
Pre-eclampsia
Pre-eclampsia or preeclampsia is a medical condition in which hypertension arises in pregnancy in association with significant amounts of protein in the urine....
during pregnancy, the congenital defect known as coarctation of the aorta, and certain prescription and illegal drugs.
Pathophysiology
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
is raised early in the disease course, with total peripheral resistance
Total peripheral resistance
Vasculature throughout the entire body can be thought of as two separate circuits - one is the systemic circulation, while the other is the pulmonary circulation. Total peripheral resistance is the sum of the resistance of all peripheral vasculature in the systemic circulation...
(TPR) normal; over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:
- Inability of the kidneys to excrete sodium, resulting in natriureticAtrial natriuretic peptideAtrial natriuretic peptide , atrial natriuretic factor , atrial natriuretic hormone , or atriopeptin, is a powerful vasodilator, and a protein hormone secreted by heart muscle cells. It is involved in the homeostatic control of body water, sodium, potassium and fat...
factors such as Atrial Natriuretic Factor being secreted to promote salt excretion with the side effectSide effectIn medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequences of the use of a drug.Occasionally, drugs are...
of raising total peripheral resistance. - An overactive Renin-angiotensin systemRenin-angiotensin systemThe renin-angiotensin system or the renin-angiotensin-aldosterone system is a hormone system that regulates blood pressure and water balance....
leads to vasoconstrictionVasoconstrictionVasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
and retention of sodium and water. The increase in blood volumeBlood volumeBlood volume is the volume of blood in the circulatory system of an individual.-Humans:A typical adult has a blood volume of approximately between 4.7 and 5 liters, with females generally having less blood volume than males....
plus vasoconstriction leads to hypertension. - An overactive sympathetic nervous systemSympathetic nervous systemThe sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
, leading to increased stress responses.
It is also known that hypertension is highly heritable and polygenic (caused by more than one gene) and a few candidate genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
have been postulated in the etiology of this condition.
Recently, work related to the association between essential hypertension and sustained endothelial damage has gained popularity among hypertension scientists. It remains unclear, however, whether endothelial changes precede the development of hypertension or whether such changes are mainly due to longstanding elevated blood pressures.
Diagnosis
Hypertension is generally diagnosed on the basis of a persistently high blood pressure. Usually this requires three separate sphygmomanometer measurements at least one week apart (see figure). Diagnosis often entails three separate visits to the physician's office. Initial assessment of the hypertensive patient should include a complete historyMedical history
The medical history or anamnesis of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information , with the aim of obtaining information useful in formulating a diagnosis and providing...
and physical examination
Physical examination
Physical examination or clinical examination is the process by which a doctor investigates the body of a patient for signs of disease. It generally follows the taking of the medical history — an account of the symptoms as experienced by the patient...
. Exceptionally, if the elevation is extreme, or if symptoms of organ damage are present, then a diagnosis may be made and treatment started immediately.
Once the diagnosis of hypertension has been made, physicians will attempt to identify the underlying cause based on risk factors and other symptoms, if present. Secondary hypertension
Secondary hypertension
Secondary hypertension is a type of hypertension which by definition is caused by an identifiable underlying secondary cause. It is much less common than the other type, called essential hypertension, affecting only 5% of hypertensive patients. It has many different causes including endocrine...
is more common in preadolescent children, with most cases caused by renal disease. Primary or essential hypertension
Essential hypertension
Essential hypertension is the form of hypertension that by definition, has no identifiable cause. It is the most common type of hypertension, affecting 95% of hypertensive patients, it tends to be familial and is likely to be the consequence of an interaction between environmental and genetic...
is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension. Laboratory tests can also be performed to identify possible causes of secondary hypertension, and to determine whether hypertension has caused damage to the heart
Human heart
The human heart is a muscular organ that provides a continuous blood circulation through the cardiac cycle and is one of the most vital organs in the human body...
, eyes, and kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s. Additional tests for diabetes and high cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
levels are usually performed because these conditions are additional risk factors for the development of heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
and require treatment. Typical tests are classified as follows:
| System | Tests |
|---|---|
| Renal Urinary system The urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder and the urethra.-Kidney:... |
Microscopic urinalysis Urinalysis A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis... , proteinuria Proteinuria Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes... , serum BUN Blood urea nitrogen The blood urea nitrogen test is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a by- product from metabolism of proteins by the liver and is removed from the blood by the kidneys.-Physiology:The liver produces urea in the urea... (blood urea nitrogen Blood urea nitrogen The blood urea nitrogen test is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a by- product from metabolism of proteins by the liver and is removed from the blood by the kidneys.-Physiology:The liver produces urea in the urea... ) and/or creatinine Creatinine Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body... |
| Endocrine Endocrine system In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. It derives from the Greek words "endo"... |
Serum sodium Sodium Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride... , potassium Potassium Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are... , calcium Calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust... , TSH Thyroid-stimulating hormone Thyrotrophin-stimulating hormone is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid gland.- Physiology :... (thyroid-stimulating hormone Thyroid-stimulating hormone Thyrotrophin-stimulating hormone is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid gland.- Physiology :... ). |
| Metabolic | Fasting blood glucose Glucose test A glucose test is a type of blood test used to determine the amount of glucose in the blood. It is mainly used in screening for any prediabetes or diabetes... , total cholesterol, HDL and LDL cholesterol, triglycerides |
| Other | Hematocrit Hematocrit The hematocrit or packed cell volume or erythrocyte volume fraction is the percentage of the concentration of red blood cells in blood. It is normally about 45% for men and 40% for women... , electrocardiogram Electrocardiogram Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body... , and chest radiograph |
| Sources: Harrison's principles of internal medicine others | |
Creatinine
Creatinine
Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...
(renal function
Renal function
Renal function, in nephrology, is an indication of the state of the kidney and its role in renal physiology. Glomerular filtration rate describes the flow rate of filtered fluid through the kidney...
) testing is done to assess the presence of kidney disease, which can be either the cause or the result of hypertension. In addition, creatinine testing provides a baseline measurement of kidney function that can be used to monitor for side effects of certain antihypertensive drugs on kidney function. Additionally, testing of urine samples for protein
Proteinuria
Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...
is used as a secondary indicator of kidney disease. Glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
testing is done to determine if diabetes mellitus is present. Electrocardiogram
Electrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...
(EKG/ECG) testing is done to check for evidence that the heart is under strain from high blood pressure. It may also show whether there is thickening of the heart muscle (left ventricular hypertrophy
Left ventricular hypertrophy
Left ventricular hypertrophy is the thickening of the myocardium of the left ventricle of the heart.-Causes:While ventricular hypertrophy occurs naturally as a reaction to aerobic exercise and strength training, it is most frequently referred to as a pathological reaction to cardiovascular...
) or whether the heart has experienced a prior minor disturbance such as a silent heart attack. A chest X-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
may be performed to look for signs of heart enlargement or damage to heart tissue.
Prevention
The degree to which hypertension can be prevented depends on a number of features including current blood pressure level, sodium/potassium balance, detection and omission of environmental toxins, changes in end/target organs (retinaRetina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
, kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
, heart, among others), risk factors for cardiovascular diseases and the age at diagnosis of prehypertension or at risk for hypertension. A prolonged assessment that involves repeated blood pressure measurements provides the most accurate blood pressure level assessment. Following this, lifestyle changes are recommended to lower blood pressure, before the initiation of prescription drug therapy. According to the British Hypertension Society, the process of managing prehypertension includes lifestyle changes such as the following:
- Weight reductionWeight lossWeight loss, in the context of medicine, health or physical fitness, is a reduction of the total body mass, due to a mean loss of fluid, body fat or adipose tissue and/or lean mass, namely bone mineral deposits, muscle, tendon and other connective tissue...
and regular aerobic exerciseAerobic exerciseAerobic exercise is physical exercise of relatively low intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means "living in air", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism...
(e.g., walkingWalkingWalking is one of the main gaits of locomotion among legged animals, and is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step...
): Regular exercise improves blood flowBlood flowBlood flow is the continuous running of blood in the cardiovascular system.The human body is made up of several processes all carrying out various functions. We have the gastrointestinal system which aids the digestion and the absorption of food...
and helps to reduce the resting heart rate and blood pressure. - Reduce dietary sugar
- Reduce sodium (salt)Sodium chlorideSodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
in the body by disuse of condiment sodium and the adoption of a high potassiumPotassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
diet which rids the renal system of excess sodium. Many people use potassium chloridePotassium chlorideThe chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...
salt substituteSalt substituteSalt substitutes are low-sodium table salt alternatives marketed to circumvent the risk of high blood pressure and cardiovascular disease associated with a high intake of sodium chloride while maintaining a similar taste...
to reduce their salt intake. - Additional dietary changes beneficial to reducing blood pressure include the DASH diet (dietary approaches to stop hypertension) which is rich in fruits and vegetables and low-fat or fat-free dairy products. Research sponsored by the National Heart, Lung, and Blood InstituteNational Heart, Lung, and Blood InstituteThe National Heart, Lung, and Blood Institute is a division of the National Institutes of Health, located in Bethesda, Maryland...
showed this diet to be effective. In addition, an increase in dietary potassiumPotassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
, which offsets the effect of sodium has been shown highly effective in reducing blood pressure. - Discontinuing tobacco use and alcohol consumptionAlcohol consumptionAlcohol consumption may refer to:* Alcohol consumption by youth in the United States* Alcoholic beverage* Legal drinking age* List of countries by alcohol consumption* Long-term effects of alcohol* Short-term effects of alcohol...
has been shown to lower blood pressure. The exact mechanisms are not fully understood, but blood pressure (especially systolic) always transiently increases following alcohol or nicotine consumption. Abstaining from cigarette smokingTobacco smokingTobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
reduces the risks of stroke and heart attack associated with hypertension. - VasodialatorsVasodilationVasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
such as niacinNiacin"Niacin" redirects here. For the neo-fusion band, see Niacin .Niacin is an organic compound with the formula and, depending on the definition used, one of the forty to eighty essential human nutrients.Niacin is one of five vitamins associated with a pandemic deficiency disease: niacin deficiency...
. - Limiting alcohol intake to less than 2 standard drinks per day can reduce systolic blood pressure by between 2-4mmHg.
- Reducing stress, for example with relaxation therapy, such as meditationMeditationMeditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....
and other mindbody relaxationMindbody relaxationThe goal of mindbody relaxation is to relax both the body and mind. The basic idea is that it's easier to relax your mind if you first relax your body. There are a variety of mindbody relaxation techniques including yoga and meditation. Mindbody meditation goes by many different names, including...
techniques, by reducing environmental stress such as high sound levelsNoise health effectsNoise health effects are the health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance and sleep disturbance. Changes in the immune system and birth defects have been attributed to noise exposure...
and over-illuminationOver-illuminationOver-illumination is the presence of lighting intensity beyond that required for a specified activity. Over-illumination was commonly ignored between 1950 and 1995, especially in office and retail environments; only since then has the interior design community begun to reconsider this practice.The...
can also lower blood pressure. Jacobson's Progressive Muscle RelaxationJacobson's Progressive Muscle RelaxationProgressive muscle relaxation is a technique for reducing anxiety by alternately tensing and relaxing the muscles. It was developed by American physician Edmund Jacobson in the early 1920s. Jacobson argued that since muscle tension accompanies anxiety, one can reduce anxiety by learning how to...
and biofeedbackBiofeedbackBiofeedback is the process of becoming aware of various physiological functions using instruments that provide information on the activity of those same systems, with a goal of being able to manipulate them at will...
are also beneficial, such as device-guided paced breathing, although meta-analysis suggests it is not effective unless combined with other relaxation techniques. - Increasing omega 3 fatty acids can help lower hypertension. Fish oil is shown to lower blood pressure in hypertensive individuals. The fish oil may increase sodium and water excretion.
- CaffeineCaffeineCaffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
raises blood pressure. - TheobromineTheobromineTheobromine , also known as xantheose, is a bitter alkaloid of the cacao plant, with the chemical formula C7H8N4O2. It is found in chocolate, as well as in a number of other foods, including the leaves of the tea plant, and the kola nut...
lowers blood pressure through its actions as both a vasodilator and a diureticDiureticA diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...
, and has been used to treat high blood pressure.
Lifestyle modifications
The first line of treatment for hypertension is identical to the recommended preventive lifestyle changes and includes:- Dietary changes
- Physical exercise
- Weight loss
These have all been shown to significantly reduce blood pressure in people with hypertension. If hypertension is high enough to justify immediate use of medications, lifestyle changes are still recommended in conjunction with medication. Drug prescription should take into account the patient's absolute cardiovascular risk (including risk of myocardial infarction and stroke) as well as blood pressure readings, in order to gain a more accurate picture of the patient's cardiovascular profile. Different programs aimed to reduce psychological stress such as biofeedback
Biofeedback
Biofeedback is the process of becoming aware of various physiological functions using instruments that provide information on the activity of those same systems, with a goal of being able to manipulate them at will...
, relaxation
Relaxation technique
A relaxation technique is any method, process, procedure, or activity that helps a person to relax; to attain a state of increased calmness; or otherwise reduce levels of anxiety, stress or anger...
or meditation
Meditation
Meditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....
are advertised to reduce hypertension. However, in general claims of efficacy are not supported by scientific studies, which have been in general of low quality.
Regarding dietary changes, a low sodium diet
Low sodium diet
A low sodium diet is a diet that includes no more than 1,500 to 2,400 mgs of sodium per day. People who follow a vigorous or moderate exercise schedule are usually advised to limit their sodium intake to 3,000 mg per day and those with moderate to severe heart failure are usually advised to...
is beneficial. A Cochrane review published in 2008 concluded that a long term (more than 4 weeks) low sodium diet in Caucasians
Caucasian race
The term Caucasian race has been used to denote the general physical type of some or all of the populations of Europe, North Africa, the Horn of Africa, Western Asia , Central Asia and South Asia...
is effective in reducing blood pressure, both in people with hypertension and in people with normal blood pressure. Also, the DASH diet (Dietary Approaches to Stop Hypertension) is a diet
Dieting
Dieting is the practice of eating food in a regulated fashion to achieve or maintain a controlled weight. In most cases dieting is used in combination with physical exercise to lose weight in those who are overweight or obese. Some athletes, however, follow a diet to gain weight...
promoted by the National Heart, Lung, and Blood Institute
National Heart, Lung, and Blood Institute
The National Heart, Lung, and Blood Institute is a division of the National Institutes of Health, located in Bethesda, Maryland...
(part of the NIH, a United States government organization) to control hypertension. A major feature of the plan is limiting intake of sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
, and it also generally encourages the consumption of nuts, whole grains, fish, poultry, fruits and vegetables while lowering the consumption of red meats, sweets, and sugar. It is also "rich in potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
, and calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, as well as protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
".
Medications
Several classes of medications, collectively referred to as antihypertensive drugs, are currently available for treating hypertension. Reduction of the blood pressureBlood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease
Ischaemic heart disease
Ischaemic or ischemic heart disease , or myocardial ischaemia, is a disease characterized by ischaemia of the heart muscle, usually due to coronary artery disease...
by 21%, and reduce the likelihood of dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...
, heart failure, and mortality
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
from cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
. The aim of treatment should be to reduce blood pressure to <140/90 mmHg for most individuals, and lower for individuals with diabetes or kidney disease (some medical professionals recommend keeping levels below 120/80 mmHg). If the blood pressure goal is not met, a change in treatment should be made as therapeutic inertia
Therapeutic inertia
Therapeutic inertia is a measurement of the resistance to therapeutic treatment for an existing medical condition. It is commonly measured as a percentage of the number of encounters in which a patient with a condition received new or increased therapeutic treatment out of the total number of...
is a clear impediment to blood pressure control. Comorbidity also plays a role in determining target blood pressure, with lower BP targets applying to patients with end-organ damage or proteinuria.
The first line antihypertensive supported by the best evidence is a low dose thiazide-based diuretic
Thiazide
Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....
.
Often multiple medications are needed to be combined to achieve the goal blood pressure. Commonly used prescription drugs include:
ACE inhibitor
ACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
s, alpha blocker
Alpha blocker
Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
s, angiotensin II receptor antagonist
Angiotensin II receptor antagonist
Angiotensin II receptor antagonists, also known as angiotensin receptor blockers , AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system...
s, beta blocker
Beta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
s, calcium channel blocker
Calcium channel blocker
A calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...
s, diuretics (e.g. hydrochlorothiazide
Hydrochlorothiazide
Hydrochlorothiazide, abbreviated HCTZ, HCT, or HZT, is a first-line diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is...
), direct renin inhibitor
Renin inhibitor
Renin inhibitor, or inhibitors of renin, are a new group of pharmaceuticals that are used primarily in treatment of hypertension.They act on the juxtaglomerular cells of kidney, which produce renin in response to decreased blood flow....
s and Glyceryl trinitrates which has the activity of vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
, thus controlling high blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
.
Some examples of common combined prescription drug include:
- A fixed combination of an ACE inhibitor and a calcium channel blocker. One example of this is the combination of perindoprilPerindoprilPerindopril, or perindopril arginine, is a long-acting ACE inhibitor. Perindopril is used to treat high blood pressure, heart failure or stable coronary artery disease. It is also available in a generic form, perindopril erbumine...
and amlodipineAmlodipineAmlodipine is a long-acting calcium channel blocker used as an anti-hypertensive and in the treatment of angina...
, the efficacy of which has been demonstrated in individuals with glucose intoleranceImpaired glucose toleranceImpaired glucose tolerance is a pre-diabetic state of dysglycemia that is associated with insulin resistance and increased risk of cardiovascular pathology. IGT may precede type 2 diabetes mellitus by many years...
or metabolic syndromeMetabolic syndromeMetabolic syndrome is a combination of medical disorders that, when occurring together, increase the risk of developing cardiovascular disease and diabetes. It affects one in five people in the United States and prevalence increases with age...
. - A fixed combination of a diuretic and an angiotensin blocker - ARBAngiotensin II receptor antagonistAngiotensin II receptor antagonists, also known as angiotensin receptor blockers , AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system...
.
Combinations of an ACE-inhibitor or angiotensin II–receptor antagonist, a diuretic and an NSAID (including selective COX-2 inhibitors and non-prescribed drugs such as ibuprofen) should be avoided whenever possible due to a high documented risk of acute renal failure. The combination is known colloquially as a "triple whammy" in the Australian health industry.
In the elderly
Treating moderate to severe high blood pressure decreases death rates in those under 80 years of age. In those over 80 years old there was a decrease in morbidity but no decrease in mortality. The recommended BP goal is <140/90 mm Hg with thiazide diuretics being the first line medication.Complications
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
thus predisposes individuals to heart disease, peripheral vascular disease, and strokes.
Types of heart disease that may occur include: myocardial infarction, heart failure, and left ventricular hypertrophy
Left ventricular hypertrophy
Left ventricular hypertrophy is the thickening of the myocardium of the left ventricle of the heart.-Causes:While ventricular hypertrophy occurs naturally as a reaction to aerobic exercise and strength training, it is most frequently referred to as a pathological reaction to cardiovascular...
Other complications include:
- Hypertensive retinopathyHypertensive retinopathyHypertensive retinopathy is damage to the retina due to high blood pressure .-Pathophysiology:The retina is one of the "target organs" that are damaged by sustained hypertension....
- Hypertensive nephropathyHypertensive nephropathyHypertensive nephropathy is a medical condition referring to damage to the kidney due to chronic high blood pressure....
- If blood pressure is very high hypertensive encephalopathy may result.
- Silent strokeSilent strokeA silent stroke is a stroke that does not have any outward symptoms, and the patient is typically unaware they have suffered a stroke. Despite not causing identifiable symptoms a silent stroke still causes damage to the brain, and places the patient at increased risk for both transient ischemic...
is a type of stroke (infarct) that does not have any outward symptoms (asymptomatic), and the patient is typically unaware they have suffered a stroke. Despite not causing identifiable symptoms a silent stroke still causes damage to the brain, and places the patient at increased risk for a major stroke in the future. Hypertension is the major treatable risk factor associated with silent stokes.
Epidemiology
In the year 2000 it is estimated that nearly one billion people or ~26% of the adult population had hypertension worldwide. It was common in both developed (333 million ) and undeveloped (639 million) countries. However rates vary markedly in different regions with rates as low as 3.4% (men) and 6.8% (women) in rural India and as high as 68.9% (men) and 72.5% (women) in Poland.In 1995 it is estimated that 43 million people in the United States had hypertension or were taking antihypertensive medication, almost 24% of the adult population. The prevalence of hypertension in the United States is increasing and reached 29% in 2004. It is more common in blacks and native Americans and less in whites and Mexican American
Mexican American
Mexican Americans are Americans of Mexican descent. As of July 2009, Mexican Americans make up 10.3% of the United States' population with over 31,689,000 Americans listed as of Mexican ancestry. Mexican Americans comprise 66% of all Hispanics and Latinos in the United States...
s, rates increase with age, and is greater in the southeastern United States
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
. Hypertension is more prevalent in men (though menopause tends to decrease this difference) and those of low socioeconomic status
Socioeconomic status
Socioeconomic status is an economic and sociological combined total measure of a person's work experience and of an individual's or family’s economic and social position in relation to others, based on income, education, and occupation...
.
Over 90–95% of adult hypertension is essential hypertension
Essential hypertension
Essential hypertension is the form of hypertension that by definition, has no identifiable cause. It is the most common type of hypertension, affecting 95% of hypertensive patients, it tends to be familial and is likely to be the consequence of an interaction between environmental and genetic...
. One of the most common causes of secondary hypertension is primary aldosteronism. The incidence
Incidence (epidemiology)
Incidence is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.Incidence proportion is the...
of exercise hypertension is reported to range from 1–10%.
In children
The prevalence of high blood pressure in the young is increasing. Most childhood hypertension, particularly in preadolescents, is secondary to an underlying disorder. Kidney disease is the most common (60–70%) cause of hypertension in children. Adolescents usually have primary or essential hypertension, which accounts for 85–95% of cases.History
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
es. Well known individuals such as The Yellow Emperor
Yellow Emperor
The Yellow Emperor or Huangdi1 is a legendary Chinese sovereign and culture hero, included among the Three Sovereigns and Five Emperors. Tradition holds that he reigned from 2697–2597 or 2696–2598 BC...
of China, Cornelius Celsus
Aulus Cornelius Celsus
Aulus Cornelius Celsus was a Roman encyclopedist, known for his extant medical work, De Medicina, which is believed to be the only surviving section of a much larger encyclopedia. The De Medicina is a primary source on diet, pharmacy, surgery and related fields, and it is one of the best sources...
, Galen
Galen
Aelius Galenus or Claudius Galenus , better known as Galen of Pergamon , was a prominent Roman physician, surgeon and philosopher...
, and Hipocrates advocated such treatments.
Our modern understanding of hypertension began with the work of physician William Harvey
William Harvey
William Harvey was an English physician who was the first person to describe completely and in detail the systemic circulation and properties of blood being pumped to the body by the heart...
(1578–1657), who was the first to describe correctly the systemic circulation of blood being pumped around the body by the heart in his book "De motu cordis". The basis for measuring blood pressure were established by Stephen Hales
Stephen Hales
Stephen Hales, FRS was an English physiologist, chemist and inventor.Hales studied the role of air and water in the maintenance of both plant and animal life. He gave accurate accounts of the movements of water in plants, and demonstrated that plants absorb air...
in 1733. Initial descriptions of hypertension as a disease came among others from Thomas Young
Thomas Young (scientist)
Thomas Young was an English polymath. He is famous for having partly deciphered Egyptian hieroglyphics before Jean-François Champollion eventually expanded on his work...
in 1808 and specially Richard Bright
Richard Bright (physician)
Richard Bright was an English physician and early pioneer in the research of kidney disease.He was born in Bristol, Gloucestershire, the third son of Sarah and Richard Bright Sr., a wealthy merchant and banker. Bright Sr. shared his interest in science with his son,encouraging him to consider it...
in 1836. The first ever elevated blood pressure in a patient without kidney disease was reported by Frederick Mahomed (1849–1884). It was not until 1904 that sodium restriction was advocated while a rice diet was popularized around 1940.
Studies in the 1920s demonstrated the public health
Public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
impact of untreated high blood pressure; treatment options were limited at the time, and deaths from malignant hypertension
Malignant hypertension
Malignant hypertension or hypertensive emergency is severe hypertension with acute impairment of an organ system and the possibility of irreversible organ-damage...
and its complications were common. A prominent victim of severe hypertension leading to cerebral hemorrhage was Franklin D. Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...
(1882–1945). The Framingham Heart Study
Framingham Heart Study
The Framingham Heart Study is a long-term, ongoing cardiovascular study on residents of the town of Framingham, Massachusetts. The study began in 1948 with 5,209 adult subjects from Framingham, and is now on its third generation of participants...
added to the epidemiological understanding of hypertension and its relationship with coronary artery disease. The National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
also sponsored other population studies, which additionally showed that African Americans had a higher burden of hypertension and its complications. Before pharmacological treatment for hypertension became possible, three treatment modalities were used, all with numerous side-effects: strict sodium restriction, sympathectomy
Sympathectomy
A Sympathectomy is a procedure during which at least one sympathetic ganglion is removed.An example is endoscopic thoracic sympathectomy....
(surgical ablation of parts of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
), and pyrogen therapy (injection of substances that caused a fever, indirectly reducing blood pressure).
The first chemical for hypertension, sodium thiocyanate
Sodium thiocyanate
Sodium thiocyanate is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthesis of pharmaceuticals and other specialty chemicals...
, was used in 1900 but had many side effects and was unpopular. Several other agents were developed after the Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, the most popular and reasonably effective of which were tetramethylammonium chloride
Tetramethylammonium chloride
Tetramethylammonium chloride is a quaternary ammonium salt with the chemical formula [4N]Cl. It is a very hygroscopic colourless solid that is soluble in water and polar organic solvents...
and its derivative hexamethonium
Hexamethonium
Hexamethonium is a ganglionic blocker, a nicotinic nACh receptor antagonist that acts in autonomic ganglia by binding mostly in or on the NN receptor, and not the acetylcholine binding site itself...
, hydralazine
Hydralazine
Hydralazine is a direct-acting smooth muscle relaxant used to treat hypertension by acting as a vasodilator primarily in arteries and arterioles...
and reserpine
Reserpine
Reserpine is an indole alkaloid antipsychotic and antihypertensive drug that has been used for the control of high blood pressure and for the relief of psychotic symptoms, although because of the development of better drugs for these purposes and because of its numerous side-effects, it is rarely...
(derived from the medicinal plant Rauwolfia serpentina
Rauwolfia serpentina
Rauvolfia serpentina, or 'snakeroot' or 'sarpagandha' is a species of flowering plant in the family Apocynaceae.-Medicinal uses:It is one of the 50 fundamental herbs used in traditional Chinese medicine, where it has the name shégēn mù or yìndù shémù .Rauwolfia serpentina contains a number of...
). A randomized controlled trial
Randomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
sponsored by the Veterans Administration
United States Department of Veterans Affairs
The United States Department of Veterans Affairs is a government-run military veteran benefit system with Cabinet-level status. It is the United States government’s second largest department, after the United States Department of Defense...
using these drugs had to be stopped early because those not receiving treatment were developing more complications and it was deemed unethical to withhold treatment from them. These studies prompted public health campaigns to increase public awareness of hypertension and the advice to get blood pressure measured and treated. These measures appear to have contributed at least in part of the observed 50% fall in stroke and ischemic heart disease between 1972 and 1994.
A major breakthrough was achieved with the discovery of the first well-tolerated orally available agents. The first was chlorothiazide
Chlorothiazide
Chlorothiazide sodium is a diuretic used within the hospital setting or for personal use to manage excess fluid associated with congestive heart failure. It is also used as an antihypertensive....
, the first thiazide
Thiazide
Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....
and developed from the antibiotic sulfanilamide, which became available in 1958; it increased salt excretion while preventing fluid accumulation. In 1975, the Lasker Special Public Health Award
Lasker Award
The Lasker Awards have been awarded annually since 1946 to living persons who have made major contributions to medical science or who have performed public service on behalf of medicine. They are administered by the Lasker Foundation, founded by advertising pioneer Albert Lasker and his wife Mary...
was awarded to the team that developed chlorothiazide. The British physician James W. Black
James W. Black
Sir James Whyte Black, OM, FRS, FRSE, FRCP was a Scottish doctor and pharmacologist. He spent his career both as researcher and as an academic at several universities. Black established the physiology department at the University of Glasgow, where he became interested in the effects of adrenaline...
developed beta blocker
Beta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
s in the early 1960s; these were initially used for angina, but turned out to lower blood pressure. Black received the 1976 Lasker Award and in 1988 the Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...
for his discovery. The next class of antihypertensives to be discovered was that of the calcium channel blockers. The first member was verapamil
Verapamil
Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, cluster headaches. It is also an effective preventive medication for migraine...
, a derivative of papaverine
Papaverine
Papaverine is an opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasm, vasospasm , and occasionally in the treatment of erectile dysfunction...
that was initially thought to be a beta blocker and used for angina, but then turned out to have a different mode of action and was shown to lower blood pressure. ACE inhibitors were developed through rational drug design
Drug design
Drug design, also sometimes referred to as rational drug design or structure-based drug design, is the inventive process of finding new medications based on the knowledge of the biological target...
; the renin-angiotensin system was known to play an important role in blood pressure regulation, and snake venom from Bothrops jararaca
Bothrops jararaca
Bothrops jararaca is a venomous pit viper species found in southern Brazil, Paraguay and northern Argentina. The species name is derived from the Tupi words yarará and ca, which means "large snake." Within its range it is often abundant and is an important cause of snakebite...
could lower blood pressure through inhibition of ACE. In 1977 captopril
Captopril
Captopril is an angiotensin-converting enzyme inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first ACE inhibitor developed and was considered a breakthrough both because of its novel mechanism of action and also because of the...
, an orally active agent, was described; this led to the development of a number of other ACE inhibitors.
Economics
The National Heart, Lung, and Blood Institute (NHLBI) estimated in 2002 that hypertension cost the United States $47.2 billion.High blood pressure is the most common chronic medical problem prompting visits to primary health care providers, yet it is estimated that only 34% of the 50 million American adults with hypertension have their blood pressure controlled to a level of <140/90 mm Hg. Thus, about two thirds of Americans with hypertension are at increased risk for heart disease. The medical, economic, and human costs of untreated and inadequately controlled high blood pressure are enormous. Adequate management of hypertension can be hampered by inadequacies in the diagnosis, treatment, and/or control of high blood pressure. Health care providers face many obstacles to achieving blood pressure control from their patients, including resistance to taking multiple medications to reach blood pressure goals. Patients also face the challenges of adhering to medicine schedules and making lifestyle changes. Nonetheless, the achievement of blood pressure goals is possible, and most importantly, lowering blood pressure significantly reduces the risk of death due to heart disease, the development of other debilitating conditions, and the cost associated with advanced medical care.,
Awareness
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...
. The World Hypertension League (WHL), an umbrella organization of 85 national hypertension societies and leagues, recognized that more than 50% of the hypertensive population worldwide are unaware of their condition. To address this problem, the WHL initiated a global awareness campaign on hypertension in 2005 and dedicated May 17 of each year as World Hypertension Day
World Hypertension Day
World Hypertension Day is a day designated and initiated by The World Hypertension League , which is itself an umbrella to organizations of 85 national hypertension societies and leagues. The day was initiated to increase the awareness of hypertension. This was especially important because of the...
(WHD
World Hypertension Day
World Hypertension Day is a day designated and initiated by The World Hypertension League , which is itself an umbrella to organizations of 85 national hypertension societies and leagues. The day was initiated to increase the awareness of hypertension. This was especially important because of the...
). Over the past three years, more national societies have been engaging in WHD and have been innovative in their activities to get the message to the public. In 2007, there was record participation from 47 member countries of the WHL. During the week of WHD, all these countries – in partnership with their local governments, professional societies, nongovernmental organizations and private industries – promoted hypertension awareness among the public through several media
Mass media
Mass media refers collectively to all media technologies which are intended to reach a large audience via mass communication. Broadcast media transmit their information electronically and comprise of television, film and radio, movies, CDs, DVDs and some other gadgets like cameras or video consoles...
and public rallies. Using mass media
Mass media
Mass media refers collectively to all media technologies which are intended to reach a large audience via mass communication. Broadcast media transmit their information electronically and comprise of television, film and radio, movies, CDs, DVDs and some other gadgets like cameras or video consoles...
such as Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
and television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
, the message reached more than 250 million people. As the momentum picks up year after year, the WHL is confident that almost all the estimated 1.5 billion people affected by elevated blood pressure can be reached.
External links
- The Framingham Heart Study
- Video showing how to measure blood pressure
- High Blood Pressure from the Heart and Stroke Foundation of Canada
- A guide to lowering high blood pressure from the National Heart, Lung, and Blood Institute
- High Blood Pressure (from the American Heart Association)
- Pulmonary Hypertension from Cleveland Clinic Online Medical Reference
- The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure