Hypertension can be classified as either essential (primary) or secondary.
Hypertension is a chronic medical condition in which the blood pressure is elevated.
It is also referred to as high blood pressure or shortened to HT, HTN or HPN.
The word “hypertension”, by itself, normally refers to systemic, arterial hypertension.
Essential or primary hypertension means that no medical cause can be found to explain the raised blood pressure. It is common. About 90-95% of hypertension is essential hypertension.
Secondary hypertension indicates that the high blood pressure is a result of (i.e., secondary to) another condition, such as kidney disease or tumours (adrenal adenoma or pheochromocytoma).
Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure.
Even moderate elevation of arterial blood pressure leads to shortened life expectancy.
|Source: American Heart Association (2003).|
Resistant hypertension is defined as the failure to reduce blood pressure to the appropriate level after taking a three-drug regimen (include thiazide diuretic).
Excessive elevation in blood pressure during exercise is called exercise hypertension.
Exercise hypertension may be regarded as a precursor to established hypertension at rest.
Signs and symptoms
Mild to moderate essential hypertension is usually asymptomatic
Accelerated hypertension is associated with
headache, somnolence, confusion, visual disturbances, nausea and vomiting (hypertensive encephalopathy).
Retinas are affected with narrowing of arterial diameter to less than 50% of venous diameter, copper or silver wire appearance, exudates, hemorrhages, or papilledema.
Some signs and symptoms are especially important in infants and neonates such as
failure to thrive, seizure, irritability, lethargy, and respiratory distress.
While in childrens hypertension may cause headache, fatigue, blurred vision, epistaxis, and bell palsy.
signs and symptoms are especially important in suggesting a secondary medical cause of chronic hypertension, such as centripetal obesity, “buffalo hump,” and/or wide purple abdominal striae and maybe a recent onset of diabetes suggest glucocorticoid excess either due to Cushing’s syndrome or other causes.
Hypertension due to other secondary endocrine diseases such as hyperthyroidism, hypothyroidism, or growth hormone excess show symptoms specific to these disease such as
in hyperthyrodism there may be
weight loss, tremor, tachycardia or atrial arrhythmia, palmar erythema and sweating.
Signs and symptoms associated with growth hormone excess
such as coarsening of facial features, prognathism, macroglossia, hypertrichosis, hyperpigmentation, and hyperhidrosis.
hyperaldosteronism may cause less specific symptoms such as
numbness, polyuria, polydipsia, hypernatraemia, and metabolic alkalosis.
A systolic bruit heard over the abdomen or in the flanks suggests renal artery stenosis.
Also radio femoral delay or diminished pulses in lower versus upper extremities suggests coarctation of the aorta.
Hypertension in patients with pheochromocytomas is usually sustained but may be episodic.
The typical attack lasts from minutes to hours and is associated with
headache, anxiety, palpitation, profuse perspiration, pallor, tremor, and nausea and vomiting.
Blood pressure is markedly elevated, and angina or acute pulmonary edema may occur.
In primary aldosteronism, patients may have
muscular weakness, polyuria, and nocturia due to hypokalemia.
Chronic hypertension often leads to left ventricular hypertrophy, which can present with exertional and paroxysmal nocturnal dyspnea.
Cerebral involvement causes stroke due to thrombosis or hemorrhage from microaneurysms of small penetrating intracranial arteries.
Hypertensive encephalopathy is probably caused by acute capillary congestion and exudation with cerebral edema, which is reversible.
Signs and symptoms associated with pre-eclampsia and eclampsia, can be
proteinuria, edema, and hallmark of eclampsia which is convulsions,
Other cerebral signs may precede the convulsion such as nausea, vomiting, headaches, and blindness.
By definition, has no identifiable cause.
It is the more common type and affects 90-95% of hypertensive patients,
even though there are no direct causes, there are many risk factors such as
sedentary lifestyle, 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, aging, inherited genetic mutations.
Family history increases the risk of developing hypertension.
Renin elevation is another risk factor, Renin is an enzyme secreted by the juxtaglomerular apparatus of the kidney and linked with aldosterone in a negative feedback loop
Also sympathetic overactivity is implicated.
Insulin resistance which is a component of syndrome X, or the metabolic syndrome is also thought to cause hypertension.
Recently low birth weight has been questioned as a risk factor for adult essential hypertension.
Secondary hypertension by definition results from an identifiable cause
Many secondary causes can cause hypertension such as
Cushing’s syndrome, which is a condition where both adrenal glands can overproduce the hormone cortisol.
Hypertension results from the interplay of several pathophysiological mechanisms regulating plasma volume, peripheral vascular resistance and cardiac output, all of which may be increased. More than 80% of patients with Cushing’s syndrome have hypertension.]
Another important cause is the congenital abnormality coarctation of the aorta.
In primary aldosteronism there is a clear relationship between the aldosterone-induced sodium retention and the hypertension.
Another related disorder that causes hypertension is apparent mineralocorticoid excess syndrome which is an autosomal recessive disorder results from mutations in gene encoding 11β-hydroxysteroid dehydrogenase which normal patient inactivates circulating cortisol to the less-active metabolite cortisone. Cortisol at high concentrations can cross-react and activate the mineralocorticoid receptor, leading to aldosterone-like effects in the kidney, causing hypertension.
Frequently, if liquorice is the cause of the high blood pressure, a low blood level of potassium will also be present.
Yet another related disorder causing hypertension is glucocorticoid remediable aldosteronism, which is an autosomal dominant disorder in which the increase in aldosterone secretion produced by ACTH is no longer transient, causing of primary hyperaldosteronism, the Gene mutated will result in an aldosterone synthase that is ACTH-sensitive, which is normally not. GRA appears to be the most common monogenic form of human hypertension.
Compare these effects to those seen in Conn’s disease, an adrenocortical tumor which causes excess release of aldosterone, that leads to hypertension.
Cushing’s syndrome which is a disorder caused by high levels of cortisol. Cortisol is a hormone secreted by the cortex of the adrenal glands
Polycystic kidney disease which is a cystic genetic disorder of the kidneys,
PKD is characterized by the presence of multiple cysts (hence, “polycystic”) in both kidneys, can also damage the liver, pancreas, and rarely, the heart and brain.
It can be autosomal dominant or autosomal recessive, with the autosomal dominant form being more common and characterized by progressive cyst development and bilaterally enlarged kidneys with multiple cysts, with concurrent development of hypertension, renal insufficiency and renal pain
chronic glomerulonephritis which is a disease characterized by inflammation of the glomeruli, or small blood vessels in the kidneys.
Hypertension can also be produced by diseases of the renal arteries supplying the kidney. This is known as renovascular hypertension; it is thought that decreased perfusion of renal tissue due to stenosis of a main or branch renal artery activates the renin-angiotensin system
also some renal tumors can cause hypertension.
Juxtaglomerular cell tumor, Wilms’ tumor, and renal cell carcinoma, all of which may produce renin.
Neuroendocrine tumors are also a well known cause of secondary hypertension.
Pheochromocytoma (most often located in the adrenal medulla) increases secretion of catecholamines such as epinephrine and norepinephrine, causing excessive stimulation of adrenergic receptors, which results in peripheral vasoconstriction and cardiac stimulation
Medication side effects
NSAIDs (Motrin/Ibuprofen) and
steroids can cause hypertension
High blood pressure that is associated with the sudden withdrawal of various antihypertensive medications is called rebound hypertension., rebound hypertension may result in a hypertensive emergency.
Rebound hypertension is avoided by gradually reducing the dose (also known as “dose tapering”), thereby giving the body enough time to adjust to reduction in dose. Medications commonly associated with rebound hypertension include centrally-acting antihypertensive agents, such as clonidine and beta-blockers.
Few women of childbearing age have high blood pressure, up to 11% develop hypertension of pregnancy.
, it may herald three complications of pregnancy:
HELLP syndrome and
neurological disease called Binswanger’s disease, causing dementia; it is a rare form of multi-infarct dementia, and is one of the neurological syndromes associated with hypertension.
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:
- Inability of the kidneys to excrete sodium, resulting in natriuretic factors such as Atrial Natriuretic Factor being secreted to promote salt excretion with the side effect of raising total peripheral resistance.
- An overactive Renin-angiotensin system leads to vasoconstriction and retention of sodium and water. The increase in blood volume leads to hypertension.
- An overactive sympathetic nervous system, 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 have been postulated in the etiology of this condition.
physical examination to confirm a diagnosis of hypertension.
Characteristically, a “hypertensive headache” occurs in the morning and is localized to the occipital region.
Other nonspecific symptoms that may be related to elevated blood pressure include dizziness, palpitations, easy fatiguability, and impotence.
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.
Tests done are classified as follows:
|Renal||Microscopic urinalysis, proteinuria, serum BUN (blood urea nitrogen) and/or creatinine|
|Endocrine||Serum sodium, potassium, calcium, TSH (thyroid-stimulating hormone).|
|Metabolic||Fasting blood glucose, total cholesterol, HDL and LDL cholesterol, triglycerides|
|Other||Hematocrit, electrocardiogram, and Chest X-ray|
Creatinine (renal function) testing is done to identify both the underlying renal disease as a cause of hypertension and, conversely, hypertension causing the onset of kidney damage.
It is a baseline for monitoring the possible side-effects of certain antihypertensive drugs later.
Glucose testing is done to identify diabetes mellitus.
Additionally, testing of urine samples for proteinuria detection is used to pick up an underlying kidney disease or evidence of hypertensive renal damage.
Electrocardiogram (EKG/ECG) testing is done to check for evidence of the heart being under strain from working against a high blood pressure
A chest X-ray might be used to observe signs of cardiac enlargement or evidence of cardiac failure.
The degree to which hypertension can be prevented depends on a number of features including: current blood pressure level, changes in end/target organs (retina, kidney, heart – among others), risk factors for cardiovascular diseases and the age at presentation.
- Weight reduction and regular aerobic exercise (e.g., walking) are recommended as the first steps in treating mild to moderate hypertension. Regular exercise improves blood flow and helps to reduce resting heart rate and blood pressure.
- Reducing dietary sugar intake.
- Reducing sodium (salt) in the diet may be effective: It decreases blood pressure in about 33% of people (see above
- Diet which is rich in fruits and vegetables and low-fat or fat-free dairy foods
- In addition, an increase in daily calcium intake has the benefit of increasing dietary potassium, which theoretically can offset the effect of sodium and act on the kidney to decrease blood pressure.
- Discontinuing tobacco use and alcohol consumption has been shown to lower blood pressure.
- Reducing stress, for example with relaxation therapy, such as meditation and other mindbody relaxation techniques
- by reducing environmental stress such as high sound levels and over-illumination can be an additional method of ameliorating hypertension.
- Jacobson’s Progressive Muscle Relaxation and biofeedback are also used,[ particularly, device-guided paced breathing, although meta-analysis suggests it is not effective unless combined with other relaxation techniques.
Lifestyle changes such as the DASH diet,
and weight loss have been shown to significantly reduced blood pressure in people with high blood pressure.
UK Hypertension guidelines
Thresholds for starting treatment
Target of treatment
|>160/100||all those with such persisting readings||<140/90|
|>140/90||If also: Cardiovascular risk >20% per 10 years
Or have established cardiovascular disease
Or have evidence end organ damage
Or chronic kidney disease without high levels albuminuria
|>130/80||Type 2 Diabetes alone||<130/80|
|>135/85||Type 1 Diabetes alone||<130/80|
|>130/80||Type 1 Diabetes with microalbuminuria
Or Type 2 Diabetes with kidney, eye or cerebrovascular damage
|>130/80||chronic kidney disease with high levels albuminuria||<125/75|
Biofeedback devices can be used alone or in conjunction with lifestyle changes or medications to monitor and possibly reduce hypertension. One example is Resperate, a portable, battery-operated personal therapeutic medical device, sold over the counter (OTC) in the United States. However, claims of efficacy are not supported by scientific studies. Testimonials are used to promote such products, while no real evidence exists that the use of resperate like devices lowers any morbidity associated with hypertension.
The aim of treatment should be blood pressure control to <140/90 mmHg for most patients, and lower in certain contexts such as diabetes or kidney disease (some medical professionals recommend keeping levels below 120/80 mmHg).
Commonly used drugs include the typical groups of
ACE inhibitors such as captopril, enalapril, fosinopril (Monopril), lisinopril (Zestril), quinapril, ramipril (Altace)
- Angiotensin II receptor antagonists may be used where ACE inhibitors are not tolerated: eg, telmisartan (Micardis, Pritor), irbesartan (Avapro), losartan (Cozaar), valsartan (Diovan), candesartan (Amias), olmesartan (Benicar, Olmetec)
- Calcium channel blockers such as nifedipine (Adalat) amlodipine (Norvasc), diltiazem, verapamil
- Diuretics: eg, bendroflumethiazide, chlorthalidone, hydrochlorothiazide (also called HCTZ).
Other additionally used groups include:
- Additional diuretics such a furosemide or low-dosages of spironolactone
- Alpha blockers such as prazosin, or terazosin. Doxazosin has been shown to increase risk of heart failure, and to be less effective than a simple diuretic.
- Beta blockers such as atenolol, labetalol, metoprolol (Lopressor, Toprol-XL), propranolol.
- Direct renin inhibitors such as aliskiren (Tekturna).
Choice of initial medication
For mild blood pressure elevation,
consensus guidelines call for medically-supervised lifestyle changes and observation before recommending initiation of drug therapy.
If lifestyle changes are ineffective, then drug therapy is initiated, often requiring more than one agent to effectively lower hypertension.
thiazide-type diuretics are better and cheaper than other major classes of drugs at preventing cardiovascular disease, and should be preferred as the starting drug.
Thiazide diuretics are effective
. Hydrochlorothiazide is perhaps the safest and most inexpensive agent
Doses in excess of 25 milligrams per day of this agent incur an unacceptable risk of low potassium or Hypokalemia.
Patients with an exaggerated hypokalemic response to a low dose of a thiazide diuretic should be suspected to have Hyperaldosteronism, a common cause of secondary hypertension.
Adverse effects of thiazide diuretics include hypercholesterolemia,
and impaired glucose tolerance with increased risk of developing Diabetes mellitus type 2.
The thiazide diuretics also deplete circulating potassium unless combined with a potassium-sparing diuretic or supplemental potassium.
Current UK guidelines suggest starting patients over the age of 55 years and all those of African/Afrocaribbean ethnicity firstly on calcium channel blockers or thiazide diuretics,
whilst younger patients of other ethnic groups should be started on ACE-inhibitors.
Subsequently if dual therapy is required to use ACE-inhibitor in combination with either a calcium channel blocker or a (thiazide) diuretic.
Triple therapy is then of all three groups and should the need arise then to add in a fourth agent, to consider either a further diuretic (e.g. spironolactone or furosemide), an alpha-blocker or a beta-blocker.
It is based upon several factors
and overall lifestyle choices
Hypertension is a risk factor for all clinical manifestations of atherosclerosis since it is a risk factor for atherosclerosis itself.
It is an independent predisposing factor for heart failure, coronary artery disease, stroke, renal disease, and peripheral arterial disease.
it is the most important risk factor for cardiovascular morbidity and mortality in industrialized countries. The risk is increased for:
- Cerebrovascular accident (CVAs or strokes)
- Myocardial infarction (heart attack)
- Hypertensive cardiomyopathy (heart failure due to chronically high blood pressure)
- Left ventricular hypertrophy – thickening of the myocardium (muscle) of the left ventricle of the heart.
- Hypertensive retinopathy – damage to the retina
- Hypertensive nephropathy – chronic renal failure due to chronically high blood pressure “benign nephrosclerosis”.
- Hypertensive encephalopathy – confusion, headahe, convulsion due to vasogenic edema in brain due to high blood pressure.
It is estimated that nearly one billion people are affected by hypertension worldwide, and this figure is predicted to increase to 1.5 billion by 2025
Over 90-95% of adult hypertension is of the essential hypertension type.
being higher in blacks and lower in whites and Mexican Americans ;
second it changes with age,
; also geographic patterns, because hypertension is more prevalent in the southeastern United States;
another important one is gender, because hypertension is more prevalent in men (though menopause tends to abolish this difference);
and finally socioeconomic status, which is an indicator of lifestyle attributes and is inversely related to the prevalence, morbidity, and mortality rates of hypertension.
For the secondary hypertension its known that primary aldosteronism is the most frequent endocrine form of secondary hypertension
The incidence of exercise hypertension is reported to range from 1 to 10% of the total population.
Hypertension often is part of the metabolic “syndrome X” its co-occurring with other components of the syndrome.
The other components are, diabetes mellitus, combined hyperlipidemia, and central obesity.
Children and adolescents
The epidemic of childhood obesity,
Renal parenchymal disease is the most common (60 to 70%) cause of hypertension.
Adolescents usually have primary or essential hypertension, making up 85 to 95% of cases
. Medical students commonly suffer from hypertension especially mature students.
Some cite the writings of Sushruta in the 6th century BC as being the first mention of symptoms like those of hypertension.
Our modern understanding of hypertension began with the work of physician William Harvey (1578–1657).
It was then recognized as a disease a century later by Richard Bright (physician) in (1789–1858).
The first ever elevated blood pressure in a patient without kidney disease was reported by Frederick Mahomed (1849–1884).
- Hypertension (High Blood Pressure)
Food/Diet Therapy for Hypertension
Vegetarians, in general, have lower blood pressure levels and a lower incidence of hypertension and other cardiovascular diseases. Experts postulate that a typical vegetarian’s diet contains more potassium, complex carbohydrates, polyunsaturated fat, fiber, calcium, magnesium, vitamin C and vitamin A, all of which may have a favorable influence on blood pressure.
A high-fiber diet has been shown to be effective in preventing and treating many forms of cardiovascular disease, including hypertension.
The types of dietary fiber is important. Of the greatest benefit to hypertension are the water soluble gel-forming fibers such as oat bran, apple pectin, psyllium seeds, and guar gum. These fibers, in addition to be of benefit against hypertension, are also useful to reduce cholesterol levels, promote weight loss, chelate out heavy metals, etc.
Sucrose, common table sugar, elevates blood pressure. Underlying mechanism is not clearly understood. It is possible that sugar increases the production of adrenaline, which in turn, increases blood vessel constriction and sodium retention.
Reduce Salt and Sodium in Your Diet
A key to healthy eating is choosing foods lower in salt and sodium
Excessive consumption of dietary sodium chloride (salt), coupled with diminished dietary potassium, induces an increase in fluid volume and an impairment of blood pressure regulating mechanisms. This results in hypertension in susceptible individuals.
A high potassium-low sodium diet reduces the rise in blood pressure during mental stress by reducing the blood vessel constricting effect of adrenaline. Sodium restriction alone does not improve blood pressure control; it must be accompanied by a high potassium intake.
Beneficial Vegetables and Spices for Hypertension
Celery (Apium graveolens). Oriental Medicine practitioners have long used celery for lowering high blood pressure.
Garlic (Allium sativum). Garlic is a wonder drug for heart. It has beneficial effects in all cardiovascular system including blood pressure.
Onion (Allium cepa). Onions are useful in hypertension. What is best is the onion essential oil. Two to three tablespoons of onion essential oil a day was found to lower the systolic levels by an average of 25 points and the diastolic levels by 15 points in hypertension subjects.
Tomato (Lycopersicon lycopersicum). Tomatoes are high in gamma-amino butyric acid (GABA), a compound that can help bring down blood pressure.
Broccoli (Brassica oleracea). This vegetable contains several active ingredients that reduce blood pressure.
Carrot (Daucus carota). Carrots also contain several compounds that lower blood pressure.
Saffron (Crocus sativus).
Saffron contains a chemical called crocetin that lowers the blood pressure.
Spices such as fennel, oregano, black pepper, basil and tarragon have active ingredients that is beneficial in hypertension