HYPERTENSION:THE SILENT AND POTENT KILLER

The Advanced Learners Dictionary by A.S. Hornby defines hypertension as ‘abnormally high blood pressure’. Research has shown that a sustained diastolic pressure greater than 90mmHg or a sustained systolic pressure in excess of 140mmHg is considered to constitute hypertension.



Hypertension could be primary or essential, secondary, salt-induced respectively. Between 90-95% of hypertensive cases are idiopathic (of unknown origin).Secondary hypertension occurs in a small percentage of patients (between 5-10%) and also caused by renal disease. Detailed studies on single gene disorder have been interpreted to favour the hypothesis that defects in renal-sodium homeostasis are the primary cause of hypertension. Rise in blood pressure is directly correlated with increasing levels of sodium intake. Genetically predisposed animals given sodium loads develop hypertension. Sodium restriction lowers blood pressure in hypertensive humans.



Aetiology of hypertension can be successfully established in only 10-15% of patients. However, a meticulous investigation of autonomic nervous system function, rennin-angiotensin system and failure of the kidney to identify a primary abnormality resulting in elevated peripheral vascular resistance in hypertensive cases. The probability of offspring inheriting hypertension has been put at 30%.
Pathogenesis of hypertension has been associated to two factors viz; genetic influences and environmental factors. Mutations occurring in genes found in enzymes controlling aldosterone metabolism ultimately result in hypertension. Examples include aldosterone synthase, 11β-hydroxylase, 17α-hydroxylase and so on.



Environmental factors that could lead to hypertension include increased salt intake (sodium), obesity, occupation, serum cholesterol levels, cigarette smoking and so on. There is a correlation between obesity and arterial pressure. Obese persons usually have elevated arterial pressure which results in hypertension. Fundamental haemodynamic variables such as cardiac output and peripheral vascular resistance play key roles in the pathogenesis of hypertension.



Hypertension is a silent, potent killer disease which can adequately be cured by a qualified medical officer through the use of antihypertensive drugs and dietary discipline. The need to be adequately informed is very essential in treating and averting hypertension.