Pathophysiology of Hypertension

Hypertension, is called 'the silent killer' as it often asymptomatic. It is one of the most common cardiovascular disease in America. There are approximately 74.5 million people who suffer from high blood pressure in the United States.

The normal blood pressure is calculated as 120/80 in a healthy adult. If the blood pressure reaches 140/90 or higher on two separate occasions, the person is said to suffer from hypertension. The blood pressure rises above 130/80 in diabetics, and they have higher risks of heart diseases.

This vascular disease occurs due to the abnormal functioning of the arterial pressure related to the central nervous system, renin-angiotensin-aldosterone system, endothelial dysfunction, genes and even due to certain environmental factors.

Those who develop a blood pressure of around 200/120, require immediate medical attention. When the blood pressure is slightly higher than 120/80, such condition is termed as pre-hypertension. This condition affects 50 million Americans and can cause damage of arteries the heart, brain and kidneys. Thus, early treatment is necessary for this condition, especially when caught during the early stages of the disease.

It is commonly observed in:

• People with family history of high blood pressure, diabetes and heart diseases
• People over 55 years of age
• Obese people
• People with very little physical activities

• Alcoholics
• Tobacco smokers
• Drug users such as cocaine
• People who eat junk food excessively

The pathophysiology of high blood pressure is unknown in 95% of the cases in America. Its pathogenesis is many times related to many factors that include excessive salt intake and genes. However, studies are carried out to establish its exact mechanism.

This type of blood pressure where exact cause cannot be pinpointed is known as essential hypertension (or primary hypertension). The hereditary factor may be one reason for essential hypertension. It is also observed that it affects more men than women.

Diet and lifestyle also play a role in the pathophysiology. Overweight people often suffer from it. Irregular sleep patterns also led to high blood pressure. It is seen in people with excessive salt intake in their diet. These people are known as 'salt sensitive'.

Their bodies exhibit high blood pressure, when the amount of salt in their blood is more than the body requirement. Low potassium and calcium intake, stress are also the causes of with high pressure.

Secondary hypertension is the condition when one can pinpoint the exact cause of hypertension. Kidney diseases is the most common factor for secondary hypertension. It can also be caused by tumors of the adrenal glands.

These tumors or abnormalities of the adrenal glands cause excessive secretion of hormones that led to hypertension. Estrogen, the hormone found in birth control pills can also cause the blood pressure to elevate. Pregnancy is another factor, that causes hypertension.

The development of arteriosclerosis and atherosclerosis are also affected by hypertension. It reduces the elasticity of arteries causing other secondary conditions which lead to decrease blood flow and ischemic diseases. Hypertension induced arteriosclerosis may led to atrophy of renal glomeruli and tubules.

This causes renal failure and may lead to death. Another serious complication arising due to hypertension is cerebrovascular diseases. Coronary diseases are the most common cause of death for hypertensive patients.

Autonomic nervous system also has a major role to play in development of hypertension. The autonomic nervous system helps in maintaining the cardiovascular homeostasis. If there is any disorder in the system, it can lead to increase in blood pressure.

The renin-angiotensin-aldosterone system helps in maintaining the extracellular fluid volume and the peripheral resistance. If this is disturbed in any way, it could lead to hypertension.

Renin is an enzyme that circulates itself to maintain the extracellular volume as well as vasoconstriction. This helps in regulating the blood pressure as it breaks down angiotensinogen secreted by the liver. Angiotensinogen is broken down to angiotensinogen I, that is further hydrolysed to angiotensin II.

This enzyme is a potent constrictor of blood vessels. It helps in raising the peripheral resistance and thus increases blood pressure. It has been found by studies, obesity increases the risk factor for activation of renin-angiotensin system. Thus, making obese people more prone to hypertension.

In order to control hypertension, you have to follow a healthy diet and maintain a balanced lifestyle. Hypertensive patients should take the following precautions:

• Quit smoking
• Reduce weight, if obese or overweight
• Eat less of junk food and more of fresh vegetables, fruits, low-fat dairy products

• Exercise regularly
• Consume about 2.3 gm of salt in your diet daily
• Reduce the intake of alcohol
• There are several medications such as diuretics, beta-blockers, calcium channel blockers which can be prescribed to keep hypertension in check

One should visit the doctor at least once a month to keep the blood pressure in check. It is not possible to prevent hypertension in many cases. But you can avoid it to an extent by following a healthy lifestyle. Prevention of the silent killer, will save you from many dreaded diseases in the future.