The effects of hypertension.

Why bother to control hypertension? The statistics, and the numbers make a compelling argument. But even more convincing is a close examination of the damage done to organs. Here is a quick tour of the vital organs--and a graphic description of what hypertension does to them.

The Arteries

For reasons that are not completely clear, hypertension hastens hardening of the arteries, a process known as arteriosclerosis, or atherosclerosis. The terms are basically synonymous, although arteriosclerosis is the broader category and includes athetoscierosis. Atherosclerosis refers to a buildup of plaque on the inside lining, called the intima, of the artery.

One theory holds that the increased pressure of the blood flow damages the intima and makes it more susceptible to narrowing by deposits of plaque and cholesterol.

Regardless of the cause, the end result is a narrowing of the bore of the artery, with a subsequent reduction of blood flow and a resulting aggravation of the pressure problem.

Where atherosclerotic disease appears determines its precise impact. In coronary arteries the result can be angina explained below) or a heart attack. If atherosclerotic narrowing of the arteries occurs in the brain, stroke can result. In kidneys, atherosclerosis can result in a reduction of the organs' filtering capabilities. As will be shown, the eyes are also susceptible. Hypertension also has some effect on the hearing mechanism.

Hypertension and the Heart

Hypertension forces the heart to pump harder in order to force the blood through narrowed arteries. As a result, the heart actually enlarges. It increases in thickness because of the additional stress and also stretches because of the larger volume of fluid it must accommodate.

When the heart stretches too far, the muscle tissue is damaged, and the heart no longer pumps as efficiently. The damage is irreversible and unfortunately can easily be overlooked in a routine physical if no electrocardiogram is taken. Once symptoms are noticed, a great deal of damage may already have been done.

Hypertension is especially related to a type of heart disease known as congestive heart failure. In this case, the enlarged heart loses its capability to push blood out of its chambers, and fluid pressure builds up on the left side of the heart. The veins cannot take this kind of pressure, and as a result, fluid is forced back into the lungs. The heart may never return to normal.

Angina (pronounced either AN-ginuh or an-JIGH-nuh) means "pain." It is caused by a lack of blood flow to the heart, which in turn is caused by atherosclerotic disease of the coronary arteries.

When the coronary arteries become partially or fully blocked, the heart muscle does not receive enough blood and therefore not enough oxygen. It cries out in pain. This effect is particularly noticeable during exertion.

Angina is often described as a squeezing, crushing discomfort or pain in the chest. Angina itself can be crippling in severe cases, and it is a precursor of other heart disease. If the blockage becomes acute, the heart's supply of oxygen will be cut off. The result is the death of heart muscle tissue--a heart attack.

An important related point: Recent research indicates that about one third of all heart attacks are so-called silent heart attacks, meaning that they were not recognized as heart attacks at the time they occurred. Silent heart attacks are very often found in hypertensive individuals. Most silent heart attacks are discovered during electrocardiograms, where the tracings will indicate past damage. That is one reason having an EKG (electrocardiogram--it is abbreviated EKG because the term was taken from the German spelling) is so important. If nothing else, it establishes a baseline from which your physician can determine if any silent damage has been done since the time of the last exam.

Hypertension and the Kidneys

Nephrosclerosis is a combination of the direct effect of the highly pressurized blood pounding on the kidneys and the atherosclerotic reduction of blood flow to the kidneys.

The result is that the kidney loses its ability to filter toxins out of the body. Most victims of this problem have no symptoms until they start to retain large amounts of fluid. At this point, the damage is difficult to reverse or irreversible. The kidneys can withstand only a certain amount of stress before they wear out. When they wear out, they will not regenerate, and dialysis may be the only answer. And when kidneys are damaged, they often cause blood pressure to increase further, a vicious cycle.

Kidney disease is a particularly unpleasant fate, and is a tragic price to pay for untreated hypertension.

Hypertension and the Brain

One effect of hypertension is known as acute hypertensive encephalopathy, a swelling of the brain and a short-circuiting of the nervous pathways. The patient requires immediate emergency treatment with powerful pharmacological agents. This condition typically affects someone with long-term blood pressure problems who has been negligent in self-care.

Here is a typical case history: One night, after an evening out with the boys (drinking and lots of salty food raise blood pressure), several cups of coffee, and a pack of cigarettes, the blood pressure goes out of sight and the brain just cannot handle the rapid use. If treated in time, the brain can be returned to normal. If not, brain injury or death may result.

Another type of brain injury linked to hypertension is an intracranial hemorrhage, one type of stroke. This is usually, though not always, a disease of the older adult who has had longstanding hypertension. Typically, the victim is on his or her feet and suddenly is gripped by a violent headache, falls down, and is comatose within seconds. What has happened is that a damaged vessel has ruptured and leaked into the brain.

A more common type of stroke (called a thrombotic stroke) occurs when a damaged vesset becomes so narrowed that blood cannot flow to a section of the brain, and artery blockage results.

A third type of stroke linked to high blood pressure occurs when an area of atherosclerotic artery roughens, allowing blood to clot on it. When the blood clot breaks loose, it lodges in a smaller artery. This is known as an embolus, and when it occurs in the brain, it can result in death of a portion of this organ (called an embolic stroke).

Incidentally, new evidence points out that the brain has its own type of angina: a condition known as a transient ischemic attack or TIA. A TIA patient appears to have had a stroke (for example, cannot speak normally) but reverts to normal in 24 hours. That time frame is the arbitrary definition of a TIA. A TIA is thought to result from small emboli (plural of embolus) thrown into the brain. While a TIA by definition does not cause permanent damage, it seems to be a precursor of future problems and apparently has a relationship to hypertension. Here, the damage is atherosclerotic.

Hypertension and the Eye

An ophthalmologist looking into a healthy eye sees a pattern of blood vessels. Uncontrolled high blood pressure, though, produces a twisting and narrowing effect, cutting off some of the eye's blood supply. Ischemia in the eye damages the retina, resulting in a variety of vision problems, including so-called tunnel vision.

Excerpted from Sandy Sorrentino, M, D., Ph,D., and Cart Hausman, Coping With High Blood Pressure (New York: Red Dembner Enterprises Corp. .