Understanding Hypertension: Causes, Classification, and Prevention, Slides of Medicine

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S O N A L I K A P O O R R O L L N O . 3 2 HYPERTENSION INTRODUCTION • Hypertension is a chronic condition of concern due to its role in the causation of coronary heart disease, stroke and other vascular complications. • It is one of the major risk factors for cardiovascular mortality, which accounts for 20-50 per cent of all deaths. • Definition and classification of hypertension refer to adults not taking anti-hypertensive drugs and not actually ill, and based on the average of two or more readings on two or more occasions after initial screening. • When systolic and diastolic blood pressure fall into different categories, the higher category should be selected to classify the individual’s blood pressure. • Isolated systolic hypertension- defined as systolic blood pressure of 140 mm of Hg and a diastolic blood pressure of less than 90 mm of Hg. • CLASSIFICATION OF BLOOD PRESSURE MEASUREMENTS CATEGORY SYSTOLIC BLOOD PRESSURE (mm of Hg) DIASTOLIC BLOOD PRESSURE(mm of Hg) Normal <120 <80 Pre-hypertension 120-139 or 80-90 hypertension Stage 1 140-159 or 90-99 Stage 2 >=160 >=100 ORGAN DAMAGE • Rate of progression of organ damage varies from one individual to another depending on many influences, most of which are incompletely understood. • Therefore, blood pressure and organ damage should be evaluated separately. • But the presence of signs of organ damage confers an increased cardiovascular risk to any level of blood pressure. KIDNEY DISEASES, TUMOR OF ADRENAL GLAND, CONGENITAL NARROWING OF AORTA AND TOXEMIAS OF PREGNANCY. MAGNITUDE OF THE PROBLEM • Worldwide raised blood pressure is estimated to cause 7.5 million deaths, about 12.8% of all the total annual deaths. • It is a major risk factor for coronary heart disease and ischaemic as well as hemorrhagic strokes. • Globally, the overall prevalence of raised blood pressure in adults aged 25 years and over was around 40% in 2008. a lar = he t=] 2 i = bo il bad Bhadd | 45.54 26S | Medd | 5.54 Urban Rusral At adolescence, men display a higher average level. Later in life the difference narrows and the pattern may even be reversed. Post menopausal changes in women may contribute to this change. • GENETIC FACTORS: the inheritance for blood pressure is polygenic. Twin studies have shown the importance of genetic factors in hypertension. The blood pressure values of monozygotic twins are usually more strongly related than those of dizygotic twins. • Family studies have shown : the children of 2 normotensive parents have 3% possibility of developing hypertension. • ETHNICITY: population studies have consistently revealed higher blood pressure levels in black communities than other ethnic groups. MODIFIABLE RISK FACTORS: • OBESITY: risk factor for hypertension. Greater the obesity, greater the blood pressure. “central obesity” indicated by an increased waist to hip ratio has been positively correlated with high BP • SALT INTAKE: high salt intake increases blood pressure proportionately. • for example: there is higher incidence of hypertension in Japan where sodium intake is above 400 mmol/day while primitive societies ingesting less than 60 mmol/day have virtually no hypertension. • SATURATED FAT: saturated fat raises blood pressure as well as serum cholesterol. • Dietary fibre: risk of CHD and hypertension is inversely proportional to consumption of dietary fibre. PREVENTION OF HYPERTENSION • The WHO has recommended the following approaches in the prevention of hypertension: • Primary prevention Population strategy High-risk strategy • Secondary prevention PRIMARY PREVENTION • Primary prevention has been defined as “all measures to reduce the incidence of disease in a population by reducing the risk of onset”. • Population strategy : directed towards the entire population irrespective of risk levels. This involves multifactorial approach based on following factors: NUTRITION: dietary changes include: reduction of salt intake to an average of more than 5 g per day Moderate fat intake Avoidance of alcohol intake Restriction of energy intake appropriate to body needs. WEIGHT REDUCTION: the prevention and correction of weight/obesity is a prudent way of reducing the risk of hypertension. This is done by: EXERCISE PROMOTION BEHAVIOURAL CHANGES: reduction of stress and smoking, yoga and transcendental meditation. SECONDARY PREVENTION • The goal of secondary prevention is to detect and control high blood pressure in affected individuals. The control measures comprise: EARLY CASE DETECTION: the only effective method of diagnosis of hypertension is to screen the population. But it is emphasised that screening should not be insisted if health resources for treatment and follow up are not adequate. • TREATMENT: In essential hypertension, as in diabetes, we cannot treat the cause, because the cause is unknown. The aim of treatment: obtain a blood pressure below 140/90 and ideally a blood pressure of 120/80. Care of hypertension must involve attention to other risk factors such as smoking and elevated bllod cholesterol levels. • PATIENT COMPLIANCE: treatment of high BP is usually life long and this presents the problem of patient compliance defined as: the extent to which patient behavior coincides with clinical prescription. CONCLUSION • Studies have shown that control of hypertension in a population is feasible, that it can be carried out through the existing system of health services in different countries, and that the control of hypertension leads to a reduction of complications such as: stroke • Heart failure • Renal failure • Some countries have launched nationwide control programs in the field of hypertension.