Essential hypertension is a disorder that results from a disruption in the normal neural, cardiovascular, endocrine, and renal systems that regulate blood pressure. Due to the complexity of factors involved in blood pressure regulation, the exact cause of essential hypertension is unknown. Disruptions among local vascular feedback mechanisms, autonomic nervous system activity, endocrine secretions from the adrenal gland, renal function of the kidney, or baroreceptor feedback and related systems within the central nervous system all represent potential etiologic agents involved in essential hypertension.
As the most prevalent condition associated with physician office visits, essential hypertension represents a major public health problem confronting most industrialized nations. Diagnosis is made based upon existing consensus reports by groups like the Joint National Committee on Prevention, Evaluation, and Treatment of Blood Pressure or the International Society of Hypertension. While all clinical researchers agree that risk for cardiovascular disease and stroke increases with increased arterial pressures, there is often disagreement regarding at which level of measured blood pressure intervention is warranted.
For example, the diagnosis of ‘pre-hypertension’ described in the JNC-7 represents a condition over which there is considerable controversy.
Prevalence rates for hypertension increase with age, and the condition is more common among African American than Caucasian patients.
Males are more likely to be diagnosed with hypertension than females prior to menopause; however, afterward hypertension among women is diagnosed at higher rates than among men. Genetics plays a role in the etiology of hypertension, and it is commonly associated with obesity, diabetes, and physical inactivity.
Epidemiologically, high blood pressure is linked to increased risk for both cardiovascular disease and cerebrovascular disease. This link appears to be the result of damage to a number of organ systems caused by sustained high blood pressure, including the enlarging of the heart muscle, called left ventricular hypertrophy, and damage to the vasculature, as evidenced by damage to the retina, peripheral blood vessels, and the microcirculatory vessels in the kidney. Obviously, hypertensive individuals who have already sustained damage to these target organs are at greater risk for subsequent heart disease and stroke than hypertensives with no target organ damage.
Unfortunately, despite the serious physiological problems and diseases associated with hypertension, the condition often goes unnoticed and undiagnosed. Part of the problem, as evident in the case of Franklin described in the Introduction to this site, is that hypertension is asymptomatic. As in Franklin’s case, the side effects of anti-hypertensive medications are often more noticeable to the patient than the condition itself, which creates complications in adhering to the treatment for this problematic medical condition.