Benign hypertension

This type of hypertension has no clearly identifiable cause, but is thought to be linked to genetics, poor diet, lack of exercise and obesity. Most people won’t notice any symptoms of essential hypertension. They usually discover that their blood pressure is high during a regular medical checkup.

Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats, it pumps blood into the arteries and presses against the artery walls. High blood pressure occurs when the walls of the arteries exert a stronger oppositional force, which requires the heart to work harder in order to move blood through the body. This results in an increase in the pressure of blood in the arteries.

Benign hypertension that runs a relatively long and symptomless course, as many as 90% to 95% of all cases of hypertension are benign (primary or essential hypertension). The remaining cases of hypertension are secondary hypertension. Secondary hypertension is high blood pressure that has an identifiable cause, such as kidney disease.
Benign hypertension

Essential hypertension - 95% of all cases of hypertension

Essential hypertension remains a major modifiable risk factor for cardiovascular disease (CVD). The current definition of hypertension (HTN) is systolic blood pressure (SBP) values of 130mmHg or more and/or diastolic blood pressure (DBP) more than 80 mmHg. There is a strong positive and continuous correlation between BP and the risk of CVD (stroke, myocardial infarction, heart failure), renal disease, and mortality, even in the normotensive range.

Essential, primary, or idiopathic hypertension is defined as high BP in which secondary causes such as renovascular disease, renal failure, pheochromocytoma, aldosteronism, or other causes of secondary hypertension or mendelian forms (monogenic) are not present.

The pathophysiology of essential hypertension depends on the primary or secondary inability of the kidney to excrete sodium at a normal blood pressure. The central nervous system, endocrine factors, the large arteries, and the microcirculation also have roles in the disorder.

Essential hypertension accounts for 95% of all cases of hypertension. Essential hypertension is a heterogeneous disorder, with different patients having different causal factors that lead to high BP. Hypertension affects more than 29% adult Americans and is the most common reason for office visits to physicians in the United States.

Essential hypertension is currently understood as a multifactorial disease arising from the combined action of many genetic, environmental, and behavioral factors.

A number of factors increase BP, including obesity, insulin resistance, high alcohol intake, high salt intake (in salt-sensitive patients), aging and perhaps sedentary lifestyle, stress, low potassium intake, and low calcium intake. Furthermore, many of these factors are additive, such as obesity and alcohol intake. Lifestyle changes are recommended for all patients: weight loss, exercise, decreased sodium intake, Dietary Approaches to Stop Hypertension (DASH) diet, and moderation of alcohol consumption.

The prevalence of hypertension is expected to increase largely due to the epidemic of obesity and the aging population in the United States.

In case the blood pressure is extremely high, there may be certain symptoms to look out for, including: severe headaches, nosebleed, fatigue or confusion, vision problems, chest pain, difficulty breathing, irregular heartbeat, blood in the urine.
Essential hypertension - 95% of all cases of hypertension

Primary and secondary hypertension

Patients with hypertension have some underlying mechanism that elevates their blood pressure. Conceptually, it is useful to think of patients with hypertension as having either essential hypertension (systemic hypertension of unknown cause) or secondary hypertension.

Approximately 90% of hypertension is idiopathic and it is specifically seen as primary (essential) hypertension. 10% of the rest is secondary for most renal diseases and coarctation of the renal artery (renovascular hypertension) which is generally caused by an atheroma plaque. Secondary hypertension develops as a result of primary aldosteronism at a low rate, and some surrenal disorders such as Cushing’s syndrome and feochromositoma.

Secondary hypertension is elevated blood pressure that results from an underlying, identifiable, often correctable cause. The prevalence of secondary hypertension is around 5-6% of all hypertensives. Because of low prevalence, routine screening for secondary hypertension is not essential and cost effective. Renal disease constitutes the major group of secondary hypertension.

Hypertension, after diabetes mellitus, is the second leading cause of end-stage renal disease (ESRD) and together these entities account for over 60% of ESRD patients.

Essential hypertension is characterized by a sustained systolic pressure of greater than 140 mm Hg and a diastolic BP at greater than 90 mm Hg. The pathophysiology of essential hypertension depends on the primary or secondary inability of the kidney to excrete sodium at a normal blood pressure. The central nervous system, endocrine factors, the large arteries, and the microcirculation also have roles in the disorder.
Primary and secondary hypertension

Risk factors for essential hypertension

One of the concepts derived from the field of epidemiology which are essential to an understanding of the etiology of illness is risk factor. A risk factor is any variable which reliably contributes to the prediction of a disorder.

By definition, the cause of essential hypertension is unknown but a number of factors are related to its development:
*Age

*Family history
The role of heredity in the etiology of essential hypertension has long been suspected. The evidences in support are the familial aggregations, occurrence of hypertension in twins, epidemiologic data, experimental animal studies and identification of hypertension susceptibility gene.

*Race
Surveys in the United States have reveled higher incidence of essential hypertension in African Americans than in whites.

*Hyperlipidaemia
*Being overweight
In both children and adults, greater body weight and increases in body weight correlate with higher blood pressure. Essential hypertension in children is frequently associated with obesity, which appears to be a contributory factor because even a modest reduction excess adiposity is associated with a reduction in blood pressure.

*Not being physically active

*Using tobacco

*Too much salt (sodium) in diet
*Too little potassium in diet
Sodium and potassium are the main extra- and intracellular ions. Interaction between the two as compared to sodium alone is associated with hypertension and increased cardiovascular risk.

*Insulin resistance

Epidemiological studies have found that low birth weight infants are at a greater risk of developing hypertension, obesity, metabolic syndrome, and diabetes as adults.
Risk factors for essential hypertension

The nature of essential hypertension

Essential or primary hypertension was considered to have no obvious cause. It comprises 90%-95% of all hypertension, with secondary hypertension (renal, endocrine and vascular) comprising the remainder.

The concept that essential hypertension has its root in childhood can be inferred from blood pressure tracking data, which demonstrate that children with elevated blood pressures will continue to have elevated blood pressures as adults.

In developed countries, the risk of becoming hypertensive during a lifetime, defined for adults as pressures greater than 140/90 mm Hg, exceeds 90%.

Essential hypertension is commonly associated with other cardiovascular risk factors such as ageing, being overweight, insulin resistance, diabetes and hyperlipidaemia.

There is a strong genetic component in essential hypertension. Essential hypertension in human is also associated with increased sodium transport in the renal proximal tubule and medullary thick ascending limb, although increased distal tubular transport has also been reported.
The nature of essential hypertension