ABSTRACT
The level of blood pressure gradually increases from birth to age 18 years. The dividing line between a normal and an abnormal blood pressure is arbitrary. However, there is a continuous relationship between the level of blood pressure and various cardiovascular events, including myocardial infarction, strokes, congestive heart failure, renal failure, and mortality. An optimal blood pressure is a systolic blood pressure less than 120 mmHg and diastolic blood pressure less than 80 mmHg. Hypertension is defined by the average of multiple measurements with either a systolic blood pressure
≥
140 mmHg or a diastolic blood pressure
≥
90 mmHg. The hallmark of hypertension is an elevated systemic vascular resistance. Hypertension
may be caused by various adrenal tumors producing cortisol, aldosterone, and norepinephrine, hyperthyroidism, hypothyroidism, hyperparathyroidism with increased parathormone and calcium, acromegaly with increased growth hormone, renal failure, renal artery stenosis resulting in renal ischemia and increased renin, and various drugs that cause salt and water retention, increase renin, or activate the sympathetic nervous system. The majority of patients with arterial hypertension do not have a known cause.
