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Types of Hypertension

Physicians classify the different kinds of hypertension based on their causes and characteristics. Following are some of the most common types.

Essential hypertension

About 90%–95% of people with high blood pressure have what’s called essential hypertension or primary hypertension. This means the condition has no identifiable source. Most experts believe essential hypertension is caused by a variety of factors, many of them as yet unknown. If this hypothesis is correct, it may explain why certain treatments lower blood pressure in some people, but not in others. For example, people who are “salt sensitive” can usually control their blood pressure with a low-sodium diet alone, while others find sodium intake has little or no influence on their hypertension.

Isolated systolic hypertension

As people age, their arteries tend to lose elasticity and become less able to accommodate blood surges. The damage created in the vessel lining when blood flows through the arteries at high pressure can be sites of plaque buildup. Eventually, these deposits lead to arteriosclerosis (hardening of the arteries). Arteriosclerosis can elevate systolic blood pressure, while diastolic pressure stays in the normal range. A systolic pressure of 140 or greater coupled with a diastolic reading of 89 or below is called isolated systolic hypertension. This is the most common form of high blood pressure in the elderly. The Framingham Heart Study, which has tracked the health of participants since the late 1940s, found that 65%–75% of people over age 65 with elevated blood pressure had isolated systolic hypertension.

In the past, doctors considered isolated systolic hypertension to be normal in elderly patients and saw no reason to treat it. However, in 1991, the Systolic Hypertension in the Elderly Program (SHEP) study provided strong evidence to the contrary. SHEP tracked 4,736 patients with isolated systolic hypertension over five years. Half the participants were placed on drugs to reduce blood pressure, while the other half received a placebo. Those taking medication had significantly fewer strokes and heart attacks than the placebo group. The SHEP study has spurred doctors to treat isolated systolic hypertension more aggressively in older patients.

A common problem

There are 690 million people throughout the world with hypertension. Even if you have normal blood pressure at age 55, you have a 90% chance of developing hypertension later in life.

Secondary hypertension

As its name implies, secondary hypertension arises from some other, often treatable, condition.

Renal artery stenosis

A common cause of secondary hypertension is renal artery stenosis, the narrowing of an artery that supplies the kidney with blood. This condition can occur as a result of a deposit of fatty material on the artery wall (atherosclerotic plaque) or, in young women, from an overgrowth of muscular tissue in the artery wall (fibromuscular dysplasia). Some cases require bypass surgery, but most can be treated successfully by angioplasty. This procedure dilates the constricted artery with an inflatable balloon that’s attached to a catheter. Angioplasty is simple, fast (30 minutes to a few hours), and relatively painless, and it requires only a small incision in an artery near the groin. From there, the physician threads the catheter through the blood vessels to the narrowed artery, using fluoroscopic (x-ray-like) images projected on a monitor as a guide. After opening the narrowed artery with the balloon, the physician usually inserts a stent, a self-expanding wire mesh tube that widens the channel.

Hyperaldosteronism

Another cause of secondary hypertension is overproduction of aldosterone, the hormone made by the adrenal glands that helps the kidneys regulate potassium and sodium levels. This condition, called hyperaldosteronism, causes the body to retain sodium and lose potassium, leading to hypertension, weight gain, muscle weakness, and water retention. If a tumor in the adrenal gland is causing the overproduction, the usual treatment is surgery. In other cases, people with this condition need only to restrict their salt intake and take a medication that blocks the action of aldosterone.

Hyperthyroidism

While he was in office, former President George H.W. Bush developed hypertension and rapid heartbeat. As it turned out, the cause was hyperthyroidism; his thyroid gland was producing too much thyroid hormone. As happens with most people treated for an overactive thyroid, President Bush’s pulse and blood pressure returned to normal after he received treatment to suppress the activity of his thyroid gland.

Pheochromocytoma

A rare, usually noncancerous tumor called a pheochromocytoma secretes excessive amounts of epinephrine and norepinephrine, which constrict most arteries and raise blood pressure. Other symptoms may include tremors, palpitations, sweating, nervousness, headache, weight loss, and fainting. Treatment consists of medications that block the hormones’ effects and surgery to remove the tumor. Pheochromocytomas are typically confined to the adrenal glands, which lie on top of the kidneys. However, about 10% spread beyond the adrenals or arise at other sites in the body. If a surgeon cannot remove the tumor, radiation or chemotherapy is necessary.

Cushing’s syndrome

Cushing’s syndrome is a hormonal disorder characterized by a high level of circulating cortisol, a hormone produced by the adrenal glands. The disorder can cause hypertension, as well as weight gain, swelling of the face, excessive body hair, acne, osteoporosis, diabetes, and a fatty deposit on the upper back called a buffalo hump. Cushing’s syndrome may be caused by excessive stimulation by the adrenal gland or, more commonly, by a person’s taking corticosteroid drugs for extended periods to treat severe allergy or autoimmune disorders. In the first case, treatment generally involves surgery. In the second, attempts are made to reduce the corticosteroid dosage.

Narrowing of the aorta

Coarctation is a rare birth defect in which the aorta, the body’s largest artery, is abnormally narrow. This condition, which may not be discovered until adulthood, causes moderate hypertension in the arms, while blood pressure in the legs is considerably lower. Often, pulses in the groin and legs are very weak or altogether absent. Symptoms include headache, fatigue, and poor circulation in the legs. Surgically repairing the narrowed artery usually alleviates the symptoms of limited blood flow, but hypertension often persists.

Medications

Many drugs, including some over-the-counter preparations, can elevate blood pressure (see “Drugs that can raise blood pressure”). Certain medications prescribed for autoimmune diseases — such as glucocorticoids (also called corticosteroids), cyclosporine, and tacrolimus — constrict blood vessels throughout the body, as do some cancer-treating agents. Hypertension may also be a side effect of nasal decongestants, anabolic steroids, or MAO inhibitors (a class of antidepressants), as well as nonsteroidal anti-inflammatory drugs known as NSAIDs (Advil, Aleve) and COX-2 inhibitors (Celebrex), two popular classes of pain relievers. In addition, NSAIDs and COX-2 inhibitors can cause kidney dysfunction, and in some cases, cardiovascular effects so discuss your personal health risks with your doctor when considering the regular use of these medications.

The decongestants found in most over-the-counter cold, flu, and allergy medicines and many weight-loss supplements can also elevate blood pressure and interfere with medications used to treat hypertension. The FDA banned one of the most common of these decongestants, phenylpropanolamine (PPA), because it was linked to an increased risk of stroke, especially in women. Fortunately, some cold, cough, and flu remedies are specially formulated for people with high blood pressure. However, it’s always a good idea to talk to your doctor before taking any over-the-counter medications.

Shortly after birth control pills came on the market in the ’60s, researchers discovered they raised blood pressure, sometimes to dangerously high levels. As a result, they were found to increase a woman’s risk of having a stroke, particularly among smokers. However, these early oral contraceptives contained considerably higher doses of estrogen and progesterone than current formulations do. Today, it’s much less common for oral contraceptives to cause hypertension, and when it does occur, it’s usually among women who smoke, are obese, or are over 35. In these cases, blood pressure usually returns to normal after the woman stops taking the pill.

The ingestion of lead and cadmium can also cause hypertension.

Drugs that can raise blood pressure

Prescription drugs

anabolic steroids

bromocriptine

ergotamine

glucocorticoids or corticosteroids (such as prednisone)

COX-2 inhibitors (such as celecoxib)

cyclosporine

disulfiram

erythropoietin

estrogens

lithium

MAO inhibitors

tacrolimus

tricyclic antidepressants

Over-the-counter drugs

nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, ibuprofen, indomethacin, naproxen

phenylephrine (found in nasal sprays)

phenylpropanolamine (an FDA-banned substance once found in appetite suppressants and in over-the-counter cold and allergy medicines)

pseudoephedrine (found in cold and allergy preparations)

White-coat hypertension

Stress can elevate blood pressure. For this reason, some people whose blood pressure is usually normal can become hypertensive in the doctor’s office. This phenomenon is dubbed white-coat hypertension. In the past, doctors often dismissed these elevated readings as a reflection of the temporary anxiety many people experience at the clinic or hospital. But now some experts think white-coat hypertension is worth investigating because it might shed light on how stress influences blood pressure.

People who are habitually affected by stress — whether from losing a job, feeling pressure at work, or simply getting stuck in traffic — may develop temporary or longer-lasting hypertension that could inflict some of the same damage as full-time hypertension.

By figuring out how these people’s blood pressure varies throughout the day, doctors can determine how best to treat them — if at all.

To get this information, patients take a portable device home with them and check their blood pressure periodically over the course of a week or two. Another option is a blood pressure monitor and cuff that you wear for 24 hours. The device automatically takes a blood pressure reading every 15–30 minutes while you go about your daily activities. This technology isn’t covered by most insurers, although a Medicare advisory committee recommended that Medicare pay for such monitoring for people who are believed to have white-coat hypertension. (See “Monitoring blood pressure at home.”)

Labile hypertension

Labile means ever-changing, and in labile hypertension, blood pressure fluctuates far more than usual. Your blood pressure might soar from 119/76 mm Hg at 10 a.m. to 170/104 mm Hg at 4 p.m. These fluctuations can spring from a variety of sources, such as too much caffeine, anxiety attacks, or stress overload. Whatever the cause, these transient episodes of hypertension can be dangerous and should be treated. As with white-coat hypertension, home blood pressure monitoring over a 24-hour period helps determine the best treatment strategy (see “Monitoring blood pressure at home”). You’re most likely to experience labile hypertension when you are in transition from normal to high blood pressure. Its duration can range from a few weeks to many years.

Resistant hypertension

Hypertension is often treated by adopting healthier habits and taking drugs to lower blood pressure, called antihypertensives. The first drug prescribed, however, doesn’t always work. Your doctor may have to increase the dose, prescribe an additional drug, or substitute a different drug. Sometimes, though, your blood pressure remains persistently elevated in spite of these efforts.

In some instances, resistant hypertension results from drug interactions. For example, antihypertensive drugs may lose their effectiveness if you’re also taking certain antidepressants or even some over-the-counter drugs, such as pain relievers, cold preparations, and diet aids. Caffeine and excessive alcohol and licorice (either as candy or as found in some chewing tobaccos) intake can also contribute to persistently high blood pressure. Other causes include panic attacks, chronic pain, sleep apnea, fluid retention, kidney damage, weight gain, and inflammatory artery disease (arteritis).

Give your doctor as much information as possible about the medications you take, the foods and drinks you consume, and any conditions you may have. There are often simple ways to avoid the interactions that render blood pressure medications ineffective.

Malignant hypertension

Though rare, malignant hypertension is the most ominous form of high blood pressure. It’s marked by an unusually sudden rise in blood pressure to dangerous levels, often with the diastolic reading reaching 130 mm Hg or higher. However, it may also occur at lower, seemingly more normal blood pressure levels if the rise is particularly abrupt. Unlike other kinds of hypertension, it’s usually accompanied by dramatic symptoms such as severe headache, shortness of breath, chest pain, nausea and vomiting, blurred vision or even blindness, seizures, and loss of consciousness.

Malignant hypertension is a medical emergency. It places people at immediate risk for heart attack, stroke, heart failure, permanent kidney damage, and bleeding in the brain. Anyone who develops the condition must be hospitalized immediately.

Malignant hypertension develops in less than 1% of people who already have high blood pressure. In rare cases, the appearance of malignant hypertension is the first sign that a person has high blood pressure. While the cause of this condition is unknown, you should never stop taking antihypertensives without your doctor’s supervision. Doing so might cause a precipitous increase in your blood pressure.

Hypertension during pregnancy

Pre-eclampsia, or hypertension during pregnancy, may appear as early as the 20th week of pregnancy and occasionally as late as one week after delivery. Occurring in about 5%–8% of all pregnancies, it’s most common among women experiencing their first pregnancy and women who already have high blood pressure. Most cases of hypertension that develop during pregnancy disappear soon after the child’s birth. Hypertension that persists is called pregnancy-induced hypertension.

The cause of pre-eclampsia is unknown. Signs of pre-eclampsia include swelling of the hands and face, blood-clotting abnormalities, and protein in the urine. For most women, pre-eclampsia never proceeds beyond the mild stage. For some women, though, the disease develops rapidly, moving from mild to severe in a matter of weeks or sometimes days. Doctors usually recommend bed rest. But if the problem remains or worsens, hospitalization and antihypertensive medications are often necessary to prevent pre-eclampsia from progressing to eclampsia, a serious medical condition. Eclampsia can cause dangerously high blood pressure, seizure, coma, and even the death of the mother, the fetus, or both. Since eclampsia frequently disappears once the baby is born, doctors often induce labor. They may also prescribe anticonvulsant medications. If the woman still has hypertension after giving birth, she may need medication. Little is known about the effects of antihypertensive agents in breast milk, however, so breast-fed infants must be closely monitored.