Hypertension

Overview
Signs/Symptoms
Causes
Tests
Treatments
Sources

What causes hypertension?
In most cases, the cause of hypertension is idiopathic. This form of high blood pressure is called essential or primary hypertension. It can affect anyone but is found more frequently in men, especially those of African descent, and it becomes very common in all Americans as they age. The National Heart, Lung, and Blood Institute estimates that as many as 1 in 3 Americans will develop high blood pressure, but about one-third of those affected do not know that they have it. In most cases, high blood pressure does not cause symptoms until it begins to damage body organs. For this reason, hypertension is sometimes referred to as the “silent killer,” quietly increasing the risk of developing stroke, heart disease, heart attack, kidney damage, and blindness. Because it is both a quiet and a common condition, blood pressure is usually evaluated each time a patient sees their doctor.

Although it may not be possible to identify the cause, there are several things that are known to increase the risk of developing hypertension and that are known to exacerbate it when it is present. These include:

Obesity
Sedentary lifestyle
Smoking
Excessive use of alcohol
Excessive dietary sodium
Use of oral contraceptives
Use of drugs such as steroids, cocaine, and amphetamines

Hypertension may also be due to an identifiable underlying condition. This form of high blood pressure is called secondary hypertension. It is important to identify the underlying conditions as they may be able to be resolved and/or controlled, allowing a person's blood pressure to return to normal or near normal levels. These conditions include:

Kidney disease or damage – decreases the removal of salts and fluids from the body, increasing blood volume and pressure. Since hypertension can also cause kidney damage, this can be a progressive problem if left untreated.
Heart disease – this may affect the force and rate of the heart’s contraction. This can also be progressive.
Diabetes – this condition can damage the kidneys and affect the integrity of the blood vessels over time.
Arteriosclerosis – a hardening of the arteries that limits their ability to dilate and constrict
Cushing’s syndrome – a disorder that involves increased production of the hormone cortisol by the adrenal gland
Hyperaldosteronism (Conn's syndrome) – a condition characterized by an overproduction of aldosterone, a hormone that helps regulate the retention and excretion of sodium by the kidneys; it may be due to an adrenal gland tumor (usually benign)
Pheochromocytoma – a tumor of the adrenal gland (rare and usually benign) that produces excessive amounts of epinephrine, a hormone that the body uses to help it respond to stress; affected patients often have severe episodes of hypertension
Thyroid disease – both excessive and deficient amounts of thyroid hormone production can cause increases in blood pressure
Pregnancy – hypertension may develop at any time during a woman’s pregnancy but is most common during the last trimester, when it can cause pre-eclampsia (toxemia), a condition characterized by increased blood pressure and retention of fluids.