Hypertension & its Cause

Hypertension

Hypertension is also called as high blood pressure. It is a condition in where the arteries have persistently elevated blood pressure. When the human heart beats then it pumps blood to the whole body through the arteries. The term blood pressure is the force of blood, pushing up against the blood vessel wall. The higher the pressure the harder the heart pump. The heart pumps blood into the arteries that carry the blood throughout the body. Hypertension is dangerous because it makes the heart work harder to pump blood to the body and contributes to hardening of the arteries, called atherosclerosis and to development of heart failure.

A blood pressure reading has a bottom number (diastolic) and top number (systolic). Hypertension can damage organs and cause several illnesses like heart failure, kidney failure, stroke and heart attack.

In American Academy of Neurology Journal, researchers reported that hypertension during middle age may raise the risk of cognitive decline later in life.

The normal level for blood pressure is below 120/80, here 120 represent the systolic measurement (peak pressure in arteries) and 80 represent the diastolic measurement (minimum pressure in arteries). Blood pressure between 120/80 and 139/89 is called prehypertension (to denote increased risk of hypertension). A blood pressure of 140/90 or above is called hypertension.

Hypertension can be classified as primary or secondary. Primary hypertension is the term for high blood pressure with unknown cause. It accounts for about 95% of cases. Secondary hypertension is the term for high blood pressure with a known direct cause, like-kidney disease, tumor, or birth control pill.

Person can have hypertension for many years without any symptom. Uncontrolled high blood pressure increases the risk of serious health problems.

Hypertension typically develops over many years. It affects nearly everyone eventually. Hypertension can be easily detected. Once people know that they have hypertension, they should consult to doctor immediately to control it.

Causes of Hypertension

The exact causes of hypertension are usually unknown; but there are several general factors that have been highly associated with the condition.

They are:

• Smoking
• Obesity or overweight
• Diabetes
• Sedentary lifestyle
• Lack of physical activity
• High levels of salt (sodium) intake.
• Insufficient potassium, calcium and magnesium consumption
• Vitamin D deficiency
• Aging
• Stress
• Tumors
• Medicines- birth control pills
• High levels of alcohol consumption
• Genetics and a family history of hypertension.  
• Chronic kidney disease
• Adrenal and thyroid problems

Based on the cause, Hypertension can be classified into two main types: 

Primary or Essential Hypertension

When a direct cause for high blood pressure can not be identified, the condition is described as primary hypertension. This hypertension makes up 90 to 95% of cases in adults, though scientists still aren’t sure exactly what causes this common form of hypertension.

Though essential hypertension remains mysterious, it has been associated to certain risk factors. Hypertension tends to run in families and affect men more than women. Age and race also play a role. In US, blacks are twice as like as whites to have hypertension.

Essential hypertension is also greatly influenced by diet and lifestyle. The relation between salt and hypertension is especially undeniable. By compare, people who do not add salt to their food show virtually no traces of essential hypertension.

The majority of all people with hypertension is "salt sensitive," that means, anything more than the minimal bodily need for salt is too much for them and increases their blood pressure. Some other factors that can raise the risk of having essential hypertension include overweight, stress, diabetes, insufficient intake of minerals like potassium, calcium or magnesium, lack of physical activity and excess alcohol consumption.

Primary hypertension is not directly attributable to one condition; it is caused by a combination of factors. Changes in the arteries over the years are often associated with hypertension. Such changes include:

• Buildup of fatty deposits inside arteries (atherosclerosis)
• Thickening of artery walls
• Excessive contraction of small arteries (arterioles)

Secondary Hypertension

When a direct cause for high blood pressure can be identified, the condition is called as secondary hypertension.  Kidney disease ranks first, among the known causes of secondary hypertension, Hypertension can also be triggered by tumors or other abnormalities that cause the adrenal glands (small glands, sit atop the kidneys) to secrete excess amounts of hormones that elevate blood pressure.

This form of hypertension makes up 5-10% of cases in adults as well as most cases in children age under 10. Secondary hypertension is the direct result of an underlying health condition that causes blood pressure to shoot up. This can have a number of causes including-

Kidney diseases

Kidney disease is the most common cause of secondary hypertension. Kidney regulates the amount of fluid in the body. If there is a kidney problem, the volume of blood can be increased. The more blood that must be pumped through artery, the higher the force that is needed.

Hypertension can be caused by several forms of kidney diseases. Diabetic nephropathy occurs when diabetes damages the kidneys’ filtering system. Polycystic kidney diseases is an inherited condition characterized by cysts in the kidney. Glomerular disease is characterized by swelling of microscopic kidney filters called glomeruli. Hypertension can also result from a blockage inside the kidney, called hydronephrosis or narrowing of arteries and leading to them renovascular hypertension.

Hormonal disorder

The adrenal glands produce hormones that affect blood pressure.  In case of Cushing’s disease, adrenal glands release too much cortisol that causes blood pressure to rise. In case of aldosteronism, they release too much aldosterone that can affect kidney function. Other glands and their hormones can play a role also. In hypothyroidism, the thyroid gland produces too little thyroid hormone that can raise blood pressure. In case of hyperthyroidism, the same gland releases too much thyroid hormone. That can also raise blood pressure by increasing the activity of two other hormones- epinephrine and nor-epinephrine. In hyperparathyroidism, the parathyroid glands secret parathyroid hormone that increase calcium in blood. So, in turn this can cause a blood pressure increase.

Birth control pills

Some birth control pills particularly those containing estrogen can raise blood pressure and also pregnancy can boost up blood pressure, because this medications can constrict blood vessels.