Secondary Hypertension

What Is It?

In most cases of high blood pressure (hypertension), there is no known cause. About 6 percent of the time, however, high blood pressure is caused by another condition or disease. When this happens, it is called secondary hypertension.

Most of the conditions that cause secondary hypertension involve the overproduction of one of the body's hormones. Some of the medical problems that can cause secondary hypertension include:

• Kidney disease Secondary hypertension related to kidney (renal) disease is called renal hypertension. The most common kind of kidney condition that leads to secondary hypertension involves abnormal narrowing of a renal artery, one of the major blood vessels that bring blood to each kidney. When the kidney's blood supply is reduced, the kidney produces high levels of a hormone called renin. High levels of renin trigger the production of other substances in the body that raise blood pressure, particularly a molecule called angiotensin II.
• Adrenal disease The adrenal glands sit on top of the kidneys and produce several hormones that can raise blood pressure. Sometimes, tumors develop in the adrenal glands, which causes the gland to produce too much of these hormones. A tumor called pheochromocytoma overproduces the hormones epinephrine (adrenalin) and norepinephrine (noradrenalin). A tumor called an aldosteronoma or Conn's syndrome overproduces the salt-retaining hormone aldosterone. Tumors in the adrenal glands or elsewhere in the body can overproduce the hormone called cortisol, which also raise blood pressure. This is known as Cushing's syndrome.
• Hyperparathyroidism A hormone called parathormone is made by two tiny glands in the neck called parathyroid glands. If the glands produce too much hormone, calcium levels in the blood increase, and this can raise blood pressure

Other causes of secondary hypertension include:

• Acromegaly
• A tumor of the pituitary gland that causes the gland to produce too much growth hormone
• Coarctation of the aorta, a malformation of the major blood vessel that carries blood from the heart to the rest of the body
• The use of oral contraceptives (rarely)

Symptoms

In high blood pressure, the systolic blood pressure (the higher of the two blood pressure numbers) is 140 millimeters of mercury (mm Hg) or above, and the diastolic blood pressure (the lower blood pressure number) is 90 mm Hg or above. In secondary hypertension, there can be other symptoms related to the medical illness that is causing the hypertension. For example, a tumor of the adrenal gland called a pheochromocytoma can cause sweating, palpitations, severe anxiety and weight loss. In Cushing's syndrome, there may be weight gain, weakness, abnormal growth of body hair and loss of menstrual periods in women, and the appearance of purple "stretch marks" on the abdomen (abdominal striae). Hyperparathyroidism with elevated calcium levels can cause extreme tiredness, mental changes (depression or confusion), nausea and vomiting, increased urination and kidney stones.

Diagnosis

You doctor will ask you if you have any symptoms related to the medical illnesses that cause secondary hypertension. During a physical examination, your doctor will pay special attention to any sudden weight gain or weight loss, signs of extra fluid in your tissues, abnormal hair growth, and purple marks on your abdomen. You doctor also will check your abdomen for any abnormal masses, and he or she will use a stethoscope to listen for sounds of abnormal blood flow in your kidneys.

Depending on the results of your physical examination, your doctor will order additional tests to pinpoint the cause of your secondary hypertension. For suspected kidney disease, these tests may include blood tests for creatinine and blood urea nitrogen (BUN), urinalysis, an ultrasound examination of your abdomen to look for swollen kidneys, an intravenous pyelogram, measurement of the chemical renin in blood from your renal veins, or scans to take pictures of your kidneys and arteries. These scans could be magnetic resonance angiography (MRA), magnetic resonance imaging (MRI) or computed tomography (CT). Occasionally, a test called a renal arteriogram is ordered. For pheochromocytoma, your urine or blood may be analyzed for levels of catecholamines (the hormones epinephrine and norepinephrine). For Cushing's syndrome, urine or blood levels of cortisol are measured. For hyperparathyroidism, blood levels of parathormone, calcium and phosphate are measured. Coarctation of the aorta shows up on chest X-rays and physical examination.

Expected Duration

Secondary hypertension will last as long as the medical problem that is causing it remains untreated.

Prevention

Most of the medical problems that cause secondary hypertension can't be prevented. This makes secondary hypertension different from essential hypertension, which can be prevented by exercising regularly, restricting salt, following a healthy diet, watching your weight and avoiding smoking.

Treatment

The treatment of secondary hypertension depends on its cause. When secondary hypertension results from a tumor or a blood vessel abnormality, surgery may be recommended. However, the decision to perform surgery is often guided by the age and general health of the patient. For some patients, anti-hypertensive medications may be a safer option than surgery.

When To Call A Professional

Call your doctor whenever you have any of the symptoms associated with medical illnesses that cause secondary hypertension, especially unexplained weight change, palpitations, edema, mental changes, abnormal hair growth or abdominal striae.

Prognosis

In many patients with secondary hypertension, high blood pressure can be cured when their underlying medical illness is treated successfully.

Additional Info

National Heart, Lung, and Blood Institute (NHLBI)

P.O. Box 30105

Bethesda, MD 20824-0105

Phone: (301) 592-8573

TTY: (240) 629-3255

Fax: (301) 592-8563

E-Mail: nhlbiinfo@rover.nhlbi.nih.gov

http://www.nhlbi.nih.gov/

American Heart Association (AHA)

7272 Greenville Ave.

Dallas, TX 75231

Toll-Free: (800) 242-8721

http://www.americanheart.org/