Hypertension

Introduction
Cause and Pathogenesis
Symptoms and Signs
Investigations and Diagnosis
Treatment and Prognosis
Prevention

Hypertension is an intermittent or persistent elevation of the blood pressure (systolic blood pressure above 140 mm Hg or diastolic blood pressure above 90 mm Hg) or (a systolic and diastolic pressure of 20 mm Hg above the normal baseline pressure). Hypertension has recently increased in incidence throughout the world. It is thought that the stresses of everyday life with a change in the dietary habits and lack of exercise has led to the increasing incidence of hypertension. Previously hypertension was predominant only in industrialized and developed countries. However, of late there has been a sudden increase in the number of cases in developing countries.

The cause of primary (essential) hypertension is not known. It is thought to be due to multiple risk factors. Known risk factors include a familial history of the disease, race, obesity, tobacco smoking, stress, and a high-fat or high-sodium diet in genetically susceptible individuals.
Extremely nervous and highly emotional people also tend to develop hypertension more readily. Secondary hypertension is related to an underlying disease process such as renal parenchymal disorders (kidney failure which is both a cause and an effect of hypertension), renal artery disease, endocrine and metabolic disorders, central nervous system disorders, and narrowing of the aorta (coarctation). It is estimated that millions of people throughout the world suffer from hypertension, that is a major causative factor in strokes, cardiac and renal disease.

Hypertension often remains asymptomatic until complications develop. It is usually discovered on blood pressure measurement during routine examination. Sometimes the patient may suffer from severe headaches, fainting attacks, dizziness, nausea and vomiting for which they seek medical attention. The chief risk of untreated hypertension is the development of complications like heart disease and strokes. Hypertensives have a much higher risk of developing strokes, heart attacks, kidney failure. They also have the risk of going blind due to damage to the eyes. Complications include atherosclerotic heart disease, cerebro vascular insufficiency with or without strokes, retinal haemorrhage in the eyes and renal failure. When the pathologic process is accelerated, malignant hypertension may result and the blood pressure becomes extremely high and nephrosclerosis, encephalopathy, and cardiac failure rapidly ensue.

For a diagnosis of hypertension, elevated blood pressures (systolic above 140mm HG or diastolic above 90 mm HG) on at least two occasions from measurements taken on three separate days are required. Secondary causes are then ruled out to make a determination of primary hypertension. Tests to rule out renal causes like a renal angiogram, blood renin levels, an ultrasound of the kidneys, and renal function tests etc. are often done especially in younger hypertensives. Hormonal tests to detect the presence of certain substances called catecholamines may be done as also tests to elicit the presence of other endocrine diseases. The aim in investigating a hypertensive is to rule out the presence of a secondary cause for the disease. E.C.G (Echocardiograms) are essential to form a baseline assessment of the patient and for follow up.

Drug therapy of hypertension is most often effective. Diuretics, beta-adrenergic blocking agents, or other types of antihypertensives like Angiotensin converting enzyme inhibitors or Calcium Channel Blockers are used to reduce blood pressure and are effective in producing good control of blood pressure. Treatment of underlying disease in secondary hypertension, exercise, restriction of dietary salt intake, decreased alcohol intake, avoidance of smoking, stress reduction, and weight reduction in obese individuals need to be attended to. Blood pressure must be monitored regularly and counselling regarding the importance of taking medications consistently should be given. Warning of the potential long-term complications of the disease is also necessary. Medications for hypertension often have to be taken life long. It has been proven that the better the control of blood pressure, the lesser the risk of complications.

As the precise cause of essential hypertension is still to be established, avoiding the known, risk factors is extremely important. Ensuring a low salt diet, avoiding high-cholesterol and fatty foods, adequate regular exercise, reduction of stress and anxiety by counselling, avoiding smoking and reducing the consumption of alcohol are the ways by which the risk factors can be avoided.