Hypertension

Synonyms :  High Blood Pressure

Clinical features, Diagnosis, Management, Prognosis, Nutrition, Herbs,

Hypertension is defined as an elevation of systolic and/or diastolic blood pressure above generally accepted normal level of up to 140/90 mm Hg for adults. However the average systolic and diastolic blood pressures gradually rise with age and some allowance has to be made for this when assessing suspected hypertension. 

Suggested guidelines for diagnosis of elevated blood pressure in adults (18 years and older) are as follows:

         Optimal blood pressure            < 120 systolic and <80 diastolic

         Normal blood pressure            <130 systolic and <85 diastolic

         High normal blood pressure            systolic 130-140 or diastolic 85-90

         Stage 1 hypertension (mild)             systolic 140-160 or diastolic 90-100

         Stage 2 hypertension (moderate)      systolic 160-180 or diastolic 100-110

         Stage 3 hypertension (severe)      systolic > 180 or diastolic > 110

Exercise, anxiety, discomfort and unfamiliar surroundings can all lead to a transient rise in blood pressure, and measurements should be repeated when the patient is resting and relaxed. For example office or white coat hypertension refers to blood pressure that is consistently elevated in the physician’s surgery but normal when measured at home. Patients who have a high blood pressure on first examination which subsequently settles with rest may not require treatment but should be kept under review because they are more likely to develop sustained hypertension. According to the guidelines, some 15% of general population (25% of adults) can be regarded as hypertensive, though only a proportion of these will be diagnosed or receive treatment.

In about 5-10% of cases, hypertension can be shown to be a consequence of a specific disease or abnormality, such as:

       Coarctation (narrowing) of the aorta, which can be a developmental abnormality or may occur in Turner’s syndrome in women (congenital chromosomal abnormality characterised by the absence of one X sex chromosome; therefore the genetic profile is 45 X0)

       Renal disease (chronic glomerulonephritis, chronic pyelonephritis, chronic renal failure, renal artery stenosis)

       Endocrine disorders

phaeochromocytoma (a benign tumour characterised by hypersecretion of 

adrenaline and noradrenaline); the main feature is occasional episodes of palpitations, tremor, sweating, flushing and throbbing headache

            Cushing’s syndrome (hypersecretion of glucocorticosteroids)

            Conn’s syndrome (hyperaldosteronism)

            acromegaly (hypersecretion of growth hormone)

            hyperthyroidism

       Excessive consumption of alcohol

       Drugs (oral contraceptives, corticosteroids, anabolic steroids) 

In the majority of patients with hypertension it is not possible to define a specific underlying cause, and they are said to have essential (idiopathic) hypertension. In 70% of such patients another member of the family is affected (positive family history). 

The pathogenesis of essential hypertension is not clearly understood. However, it is known that the underlying defect is increase in peripheral vascular resistance. Some believe that this is due to increase in sympathetic nervous activity while others believe that there is a fundamental defect in the vascular smooth muscle related to abnormal transport of ions across the cell membrane and increased sensitivity to sympathetic stimulation. Excessive water and sodium retention by the kidneys and deficiency of vasodilator substances (e.g., bradykinin) have also been suggested. 

Long-standing hypertension causes irreversible changes in peripheral blood vessels in form of arteriolosclerosis (concentric thickening of small arterial blood vessels) when high blood pressure is established permanently. This narrowing of blood vessels causes progressive ischaemia of tissues, which could be responsible for certain complications of hypertension especially in the retina and kidneys.

Clinical features:  < BACK TO TOP >

       Hypertension is often referred to as a “silent killer?because most patients initially remain asymptomatic, and the diagnosis is therefore usually made at routine examination.

       Occasionally headache or polyuria (abnormally large quantities of urine with frequent urination) appear; however most patients with hypertension do not get headaches.

       Complications occur in long standing cases giving rise to relevant symptoms:

1. Central nervous system

stroke (a major cause of death in hypertensive patients) caused by cerebral infarction or haemorrhage

hypertensive encephalopathy, a rare condition characterised by a very high    

blood pressure that leads to cerebral oedema and serious neurological symptoms such as severe headache, nausea, vomiting, transient disturbances of speech and vision, paraesthesiae (tingling), paresis (weakness) of muscles, convulsions and loss of consciousness

2. Retina

hypertensive retinopathy (progressive irreversible changes in the retina of the eye causing eventually visual field defects or even blindness)

3. Heart

left ventricular hypertrophy due to increased cardiac workload and in time left ventricular failure (so called hypertensive heart disease)

                    increased incidence of atherosclerosis and coronary artery disease

4. Kidneys

proteinuria and progressive chronic renal failure (the most common cause of chronic renal failure is diabetes mellitus, followed by long-standing hypertension)

Diagnosis:  < BACK TO TOP >

       Regular measurements of the blood pressure are necessary to establish the existence of hypertension with certainty; at least two blood pressure determinations should be taken on each of 3 consecutive days before a patient is diagnosed as hypertensive.

       Urine analysis for proteins (may indicate renal disease) and glucose (diabetes may coexist and is a risk factor for vascular disease) is routinely carried out; plasma urea/creatinine and creatinine clearance are measured to assess renal function.

       Plasma electrolytes can also provide important clues; hypokalaemic alkalosis may indicate primary (Conn’s syndrome) or secondary hyperaldosteronism (found in heart failure, liver cirrhosis and treatment with diuretic drugs).

       Plasma total cholesterol, LDL and HDL are also ordered because hypercholesterolaemia is an important risk factor for vascular disease.

       Chest X-ray can be used to detect cardiomegaly (enlargement of the heart) or heart failure; ultrasound can be used to check for cardiac hypertrophy or signs of weakening of the heart.

       ECG can reveal left ventricular hypertrophy (hypertensive heart disease) and myocardial ischaemia in coronary heart disease.

       24-hour urine collection for metanephrine or vannylmandelic acid excretion (adrenaline metabolites) can be done if history suggests phaechromocytoma.

       Intravenous urogram (administration of a contrast medium which is excreted through the kidney and recording X-ray during this process) may be scheduled if renal disease is suspected.

       Radionuclide renography (similar to urogram but a radionuclide is given and radiation is detected by a gamma camera) is used to assess renal function.

Management  < BACK TO TOP >

       The object of treating systemic arterial hypertension is to reduce the risk of complications and to improve patient survival.

       General measures such as reducing alcohol consumption and intake of salt, correcting obesity, stopping smoking, taking regular exercise, avoiding stress, relaxation techniques, massage and aromatherapy alone may be sufficient in certain number of patients.

       Thiazide diuretics (bendrofluazide [Aprinox], hydrochlorothiazide [Diclotride] and cyclopenthiazide [Navidrex]) are effective but may take up to a month for the maximum effect to be observed (warning: these drugs may cause reversible male impotence, and also can worsen type II diabetes and gout).

       b₁-adrenoceptor antagonists (atenolol [Tenormin, Anselol] and metoprolol [Betaloc, Lopressor]) reduce blood pressure by reducing cardiac output; a₁/b-antagonists (e.g., carvedilol [Dilatrend]) work by reducing both cardiac output and peripheral vascular resistance.

       Angiotensin converting enzyme (ACE) inhibitors (captopril [Capoten], enalapril [Renitec], lisinopril [Prinvil], fosinopril [Monopril], ramipril [Tritace, Ramace], perindopril [Coversyl]) have been a major advance in the treatment of hypertension (sometimes cause dry cough).

       Angiotensin II antagonists (losartan [Cozaar], irbesartan [Avapro] and telmisartan [Pritor, Micardis]) are the latest addition to antihypertensive treatment (their advantage over ACE inhibitors is that they don’t cause cough).

       Calcium antagonists (nifedipine [Adalat, Nifecard], verapamil [Isoptin, Cordilox, Veracaps], felodipine [Plenidil, Agon] and amlodipine [Norvasc]) are particularly useful when hypertension coexists with angina.

       a₁-adrenoceptor antagonists such as prazosin [Minipress, Pressin], doxazosin [Carduran] and terazosin [Hytrin] reduce blood pressure by causing peripheral vasodilation.

Prognosis  < BACK TO TOP >

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Nutrition < BACK TO TOP >

Nutrition that alleviate or prevent Hypertension :-
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Herbs < BACK TO TOP >

Herbs that alleviate or prevent Hypertension :-
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