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Hypertension

Hypertension is defined as blood pressure that is higher than 140/90 mm Hg (below 120/80 mm Hg is considered normal). There are two types of hypertension—primary and secondary (which includes endocrine hypertension). Most hypertension is the primary type. Its cause is unknown, but genetics and risk factors such as eating too much salt, being obese, and using tobacco, alcohol, and certain medications contribute to it. Primary hypertension usually responds well to lifestyle changes and blood pressure medications. Secondary hypertension requires a different type of treatment. It is a result of (secondary to) another condition, and so the underlying cause must be identified and treated.

Secondary hypertension can be caused by an adrenal gland disorder, most often:

Renovascular hypertension is another form of secondary hypertension. This occurs when the arteries that carry blood to the kidneys become narrow (usually due to plaque buildup) and less blood flows to the kidneys. The kidneys mistakenly respond as if blood pressure is low, and release hormones that raise blood pressure.

Having either too much thyroid hormone (called hyperthyroidism)or too little (hypothyroidism), or having too much parathyroid hormone (hyperparathyroidism) are other endocrine conditions that can contribute to secondary hypertension.

Some medications can cause secondary hypertension, including birth control pills, menopausal estrogen therapy, and corticosteroids—anti-inflammatory drugs that treat arthritis, asthma, and other conditions.

Depending on its cause, secondary endocrine hypertension can be successfully treated by surgery or medications.

Primary Aldosteronism and Endocrine Hypertension

Primary aldosteronism (PA) is a condition that results when one or both of the adrenal glands—two small glands located above each kidney—make too much of the hormone aldosterone. Having high levels of aldosterone causes the body to retain sodium (salt) and lose potassium. Sodium retention causes fluid build-up, which raises blood pressure.

PA occurs in as many as one in ten people with high blood pressure. PA is more common in people with severe, uncontrolled high blood pressure or blood pressure that is resistant to drug treatment. People with PA have a higher risk of heart disease and stroke than other people with the same degree of high blood pressure but without PA.

Who should be tested for PA?

Certain groups of people are at high risk for PA and should be tested, including those with

  • moderate, severe, or resistant high blood pressure (resistant means that three medications taken at the same time fail to bring the blood pressure into the normal range)
  • high blood pressure and a low level of potassium in the blood
  • high blood pressure and an adrenal tumor
  • high blood pressure at a young age
  • family history of stroke at a young age
  • high blood pressure and a parent, sibling, or child with PA

Diagnosis of PA

A blood test called the aldosterone/renin ratio (ARR) is used to detect PA. Renin is a protein released by the kidneys to help regulate blood pressure. This test measures levels of aldosterone and renin in the blood. Diagnosis of PA is based on having both very high levels of aldosterone and low levels of renin.

Treatment of PA

Treatment of PA depends on the underlying cause.

  • Aldosterone-producing adenoma (a noncancerous tumor): If only one adrenal gland is making too much aldosterone, it can be surgically removed. Some people continue to have high, but less severe, blood pressure after surgery, but it can be managed with medication more easily than before surgery.
  • Hyperplasia (excessive growth of cells): If both adrenals are overactive, surgery is not usually recommended. Instead, PA is treated with a medication such as spironolactone can block the action of aldosterone in the body.

Cushing Syndrome and Endocrine Hypertension

Cushing syndrome (CS) occurs when there is too much cortisol in the bloodstream for a long time. Cortisol is a steroid hormone produced by the adrenal glands. Some of the signs and symptoms of CS are:

  • weight gain (especially around the abdomen)
  • rounded face
  • extra fat on the upper back and above the collarbones
  • thick reddish-purple stretch marks
  • easy bruising of the skin
  • high blood sugar (diabetes)
  • high blood pressure

In normal amounts, cortisol helps the body maintain blood pressure and the work of the cardiovascular system. But too much cortisol can cause hypertension.

There are two types of CS—exogenous and endogenous. Exogenous means the cause is external to the body; endogenous means the cause is internal. Exogenous (external) CS is caused by taking medication containing glucocorticoids (cortisol-like medications) such as dexamethasone or prednisone. It goes away when, under the direction of a physician, a person stops taking those medications.

Endogenous (internal) CS is caused by the body’s overproduction of cortisol. It usually develops slowly and can be hard to diagnose. The problem could be an adrenal gland tumor (usually noncancerous) that produces too much cortisol. More likely, it could be a pituitary gland tumor that produces too much adrenocorticotropic hormone (ACTH), the hormone that tells the adrenals to make cortisol. (The pituitary is a thumbnail-sized gland located at the base of the brain that controls the function of other endocrine glands.) Rarely, a non-pituitary tumor can cause CS by producing too much ACTH. In people with endogenous CS, about 80 percent of adults and about half of children and adolescents have hypertension.

Who should be tested for endogenous CS?

Certain people should be tested for endogenous CS:

  • People with unusual signs and symptoms for their age, such as osteoporosis (weak bones), high blood pressure, diabetes, or thin skin in younger people.
  • People with several symptoms of CS that are getting worse, such as reddish-purple stretch marks, extra fat on the upper back and above the collarbones, and weight gain around the belly.
  • Children with poor height growth and increasing weight.
  • People with a mass (tumor) on the adrenal gland.

Diagnosis of endogenous CS

Several tests measure cortisol levels in the urine, saliva, or blood. CS is diagnosed when levels of cortisol are high.

Treatment of endogenous CS

Surgery to remove the tumor is the usual treatment. For most people surgery is successful, but some may also need radiation therapy or drugs to lower cortisol production. Most people with CS have very good treatment results.

Pheochromocytoma and Endocrine Hypertension

Pheochromocytoma is a rare, usually noncancerous adrenal gland tumor that produces excess epinephrine (adrenaline) and norepinephrine (noradrenaline), hormones called catecholamines. The body needs norepinephrine to maintain blood pressure, but its overproduction causes a dangerous rise in blood pressure. The symptoms of pheochromocytoma include episodic severe headaches, excess sweating, racing heart, feelings of anxiety or nervousness, and trembling, among others.

Who should be tested for pheochromocytoma?

People with the symptoms of excess catecholamines should be tested for pheochromocytoma, particularly if they

  • have very hard-to-control hypertension
  • need more than three medications to normalize blood pressure
  • have hypertension that began before age 35

Diagnosis of pheochromocytoma

Diagnosis can be made by urine or blood tests. These tests measure levels of catecholamines and metanephrines, which are chemical compounds related to adrenaline. In pheochromocytoma, levels of these substances are too high.

Treatment of pheochromocytoma

Pheochromocytomas are usually removed surgically. Before surgery, alpha- and beta-blocker medications are needed to bring hypertension under control and prevent complications during surgery.

Editors:

Gordon H. Williams, MD
Brigham and Women's Hospital

William F. Young, Jr., MD
Mayo Clinic

Last revised: April 2013