High blood pressure dangers: Hypertension's effects on your body

High blood pressure is a "silent killer." Learn how to stop its stealth attack on vital organs.

Often called the silent killer, high blood pressure can quietly damage your body for years before symptoms develop. Left uncontrolled, you may wind up with a disability, a poor quality of life or even a fatal heart attack.

Learn more about high blood pressure so that you know what's at stake and can gain a better sense of why successfully managing your high blood pressure is so important.

Here's a look at the complications high blood pressure (hypertension) can cause when it's not effectively controlled.

Damage to your arteries

Healthy arteries are flexible, strong and elastic. Their inner lining is smooth so that blood flows freely, supplying vital organs and tissues with adequate nutrients and oxygen. If you have high blood pressure, the increased pressure of blood flowing through your arteries gradually can cause a variety of problems, including:

• Arteriosclerosis and atherosclerosis. The excessive pressure in your arteries from high blood pressure alters the cells of the arteries' inner lining. That launches a cascade of events that make artery walls thick and stiff, a disease called arteriosclerosis (ahr-teer-e-o-skluh-RO-sis), or hardening of the arteries. Circulating fats pass through the altered cells and accumulate to start the process of atherosclerosis. These changes can affect arteries throughout your body, obstructing blood flow to your heart, kidneys, brain and extremities. The damage can cause chest pain (angina), heart attack, heart failure, kidney failure, stroke, peripheral arterial disease and aneurysms.
• Aneurysm. Over time, the constant pressure of blood coursing through a weakened artery can cause a section of its wall to enlarge and form a bulge (aneurysm). An aneurysm (AN-u-rizm) can rupture and cause life-threatening internal bleeding. Aneurysms can form in any artery throughout your body, but they're most common in the aorta, your body's largest artery.

Damage to your heart

Your heart is responsible for pumping blood to your entire body. Uncontrolled high blood pressure can damage your heart in a number of ways, such as:

• Coronary artery disease (CAD). This is a cluster of diseases involving the arteries that supply blood to your heart muscle. Changes to the cells lining these arteries reduce the ability of the arteries to dilate, which can cause chest pain (angina). CAD also occurs when blood flow through your arteries becomes obstructed, usually because of atherosclerosis. When blood can't flow freely to your heart, you can experience chest pain, a heart attack or irregular heart rhythms (arrhythmias). People with high blood pressure who have a heart attack are more likely to die of that heart attack than are people who don't have high blood pressure.
• Enlarged left heart. High blood pressure forces your heart to overexert itself. This causes the left ventricle to enlarge (left ventricular hypertrophy) — just as your biceps get bigger when you lift weights. This enlargement limits the ventricle's ability to expand sufficiently and to completely fill with blood. In turn, the ventricle can't pump out as much blood to your body. This condition increases your risk of heart attack, heart failure and sudden cardiac death.
• Heart failure. Over time, the added exertion demanded by high blood pressure can cause your heart muscle to weaken and work less efficiently. Eventually, your overwhelmed heart simply begins to wear out and fail. Damage from heart attacks adds to this problem.

Damage to your brain

Just like your heart, your brain depends on a nourishing blood supply to function properly and survive. But high blood pressure can cause several problems, including:

• Transient ischemic attack (TIA). Sometimes called a ministroke, a transient ischemic (is-KEM-ik) attack is a brief, temporary obstruction of blood supply to your brain. It's often caused by atherosclerosis or a blood clot — both of which can arise from high blood pressure. A transient ischemic attack is often a warning that you're at risk of a full-blown stroke.
• Stroke. A stroke occurs when part of your brain is deprived of oxygen and nutrients, causing brain cells to die. Uncontrolled high blood pressure can lead to stroke by damaging and weakening your brain's blood vessels, causing them to narrow, rupture, or leak. High blood pressure can also cause an aneurysm — a bulge in the blood vessel wall that can burst, causing life-threatening bleeding in the brain.
• Dementia. Dementia is a brain disease resulting in impaired thinking, speaking, reasoning, memory, vision and movement. Vascular dementia can result from extensive narrowing and blockage of the arteries that supply blood to the brain. It can also result from strokes caused by an interruption of blood flow to the brain. In either case, high blood pressure may be the culprit. High blood pressure that occurs even as early as middle age can increase the risk of dementia in later years.
• Mild cognitive impairment. Mild cognitive impairment is a transition stage between the cognitive changes of normal aging and the more serious problems caused by Alzheimer's disease. Like dementia, it can result from impaired blood flow to the brain when high blood pressure damages arteries. This condition can affect many areas of cognition, such as language, attention, critical thinking, reading, writing, reaction time and memory.

Damage to your kidneys

Your kidneys are responsible for filtering and excreting excess fluid and waste from your blood — processes that are highly dependent on your blood vessels. High blood pressure can injure both the blood vessels in and leading to your kidneys, causing several types of kidney disease (nephropathy). Having diabetes in addition to high blood pressure can worsen the damage.

• Kidney failure. High blood pressure is one of the most common causes of kidney (renal) failure. That's because it can damage both the large arteries leading to your kidneys and the tiny blood vessels (glomeruli) within the kidneys. Damage to either disrupts the ability of your kidneys to filter waste products from your blood. As a result, dangerous levels of fluid and waste can accumulate. You might ultimately require dialysis or kidney transplantation.
• Kidney scarring (glomerulosclerosis). Glomerulosclerosis (glo-mer-u-lo-skluh-RO-sis) is a type of kidney damage caused by scarring of the glomeruli (glo-MER-u-li). The glomeruli are tiny clusters of blood vessels within your kidneys that filter fluid, waste and other substances from your blood. Glomerulosclerosis can leave your kidneys unable to filter waste effectively, ultimately leading to kidney failure.
• Kidney artery aneurysm. An aneurysm is a bulge in the wall of a blood vessel. When it occurs in an artery leading to the kidney, it's known as a kidney (renal) artery aneurysm. One potential cause is atherosclerosis, which weakens and damages the artery wall. Over time, the excessive pressure of blood coursing through a weakened artery can cause a section to enlarge and form a bulge — the aneurysm. Aneurysms can rupture and cause life-threatening internal bleeding.

Damage to your eyes

Tiny, delicate blood vessels supply blood to your eyes. Like other vessels, they, too, are vulnerable to the damage of high blood pressure:

• Eye blood vessel damage (retinopathy). High blood pressure can damage the vessels supplying blood to your retina. Damaged enough, the blood vessels can leak or become blocked, resulting in retinopathy. This condition can lead to bleeding in the eye, microaneurysms, swelling of the optic nerve, blurred vision and complete loss of vision. If you also have both diabetes and high blood pressure, you're at an even greater risk.
• Fluid buildup under the retina (choroidopathy). In this condition, fluid accumulates under the retina because of a leaky blood vessel in the choroid, a layer of blood vessels located under the retina. Choroidopathy (kor-oid-OP-uh-thee) can result in vision distortion or in some cases scarring that impairs vision.
• Nerve damage (optic neuropathy). This is a condition in which blocked blood flow damages the optic nerve. It can lead to the death or dysfunction of optic nerve cells, which may cause bleeding within your eye or vision loss.

High blood pressure emergencies

High blood pressure is typically a chronic condition that gradually causes damage over the years. In some cases, though, blood pressure rises so quickly and severely that it constitutes a medical emergency requiring immediate treatment, often with hospitalization.

In these situations, high blood pressure can cause:

• Brain dysfunction marked by memory loss, personality changes, trouble concentrating, lethargy, or progressive loss of consciousness. (encephalopathy)
• Stroke
• Severe damage to your heart's main artery (aortic dissection)
• Seizures in pregnant women (eclampsia)
• Unstable chest pain (angina)
• Heart attack
• Impaired pumping of the heart leading to fluid backup in the lungs resulting in shortness of breath (pulmonary edema)
• Sudden loss of kidney function (acute renal failure)

In most cases, these emergencies arise because high blood pressure hasn't been adequately controlled.

Other possible dangers of high blood pressure

Evidence is mounting that high blood pressure can also affect other areas of the body, leading to such problems as:

• Sexual dysfunction. Although the inability to have and maintain an erection (erectile dysfunction) becomes increasingly common in men as they reach age 50, it's even more likely to occur if they have high blood pressure, too. Evidence linking high blood pressure to sexual dysfunction in women isn't conclusive.
• Bone loss. High blood pressure can increase the amount of calcium that's eliminated in the urine. That excessive elimination of calcium may lead to loss of bone mineral density (osteoporosis), which in turn can lead to fractures. The risk is especially increased in older women.
• Trouble sleeping. Obstructive sleep apnea — a condition where your throat muscles relax causing you to snore loudly — occurs in more than half of those with high blood pressure.  It's now thought that high blood pressure itself may help trigger sleep apnea. Also, sleep deprivation resulting from sleep apnea can raise your blood pressure.

Prevention makes a difference

High blood pressure's complications are serious. But if your blood pressure is well controlled, you're more likely to keep the most severe problems at bay.

Adopting healthy lifestyle changes can help you manage your disease. For example, reducing your sodium (salt) intake and losing even a little weight can have a dramatic impact on your high blood pressure.

You may also need to take high blood pressure medications. Many of these medications have the added benefit of helping prevent specific complications, such as heart or kidney disease.

Working closely with your health care team, you can get a handle on your blood pressure and live a healthier life.