DIABETES AND ENDOCRINE SYSTEM Endocrine System • Graves' disease • Hypoglycemia • Goiter • Male hypogonadism • Gestational diabetes • Type 1 diabetes • Hyperthyroidism • Hypothyroidism • Addison's disease • Hyperparathyroidism • Diabetic retinopathy • Cushing's syndrome • Acromegaly • Hypopituitarism • Thyroid nodules • Metabolic syndrome • Prolactinoma • Pituitary tumors • Dehydration • Primary aldosteronism • Hashimoto's disease • Pheochromocytoma • Type 2 diabetes • Prediabetes • Diabetic coma • Diabetic hyperosmolar syndrome • Diabetic ketoacidosis • Diabetes insipidus

Note: All links within content go to MayoClinic.com

A pheochromocytoma (fe-o-kro-mo-si-TOE-muh) is a rare tumor that develops in the core of an adrenal gland. You have two adrenal glands, one just above each of your kidneys. Your adrenal glands produce hormones that give instructions to virtually every organ and tissue in your body.

If you have a pheochromocytoma, your adrenal glands can produce too much of certain hormones, raising your blood pressure and heart rate. A pheochromocytoma may be life-threatening if unrecognized or untreated.

A pheochromocytoma can develop at any age, but most commonly occurs in people between ages 40 and 60. Most of the time, a pheochromocytoma is noncancerous (benign), and treatment can return blood pressure to normal.

A pheochromocytoma can result in excessive secretion of the hormones adrenaline (epinephrine) and noradrenaline (norepinephrine). The excess secretion can be either continuous or occur in shorter bursts, leading to persistent high blood pressure or wild fluctuations.

Many people have episodes of signs and symptoms related to the intermittent release of these hormones. In addition to high blood pressure, you may experience the following signs and symptoms:

• Rapid heart rate
• Irregular heartbeat (palpitations)
• Excessive sweating
• Chest pain
• Upper abdominal pain
• Severe headaches
• Shaking (tremors) of your hands
• Feeling of anxiety
• Feeling of extreme fright
• Pale skin

The signs and symptoms you experience are typically the same with each episode.

An attack of high blood pressure (hypertensive crisis) may be brought on by physical activities that press on the tumor, or other events, such as:

• Changes in body position
• Exercise
• Lifting
• Defecation
• Emotional distress or anxiety
• Receiving anesthesia

Other triggers include the use of drugs or stimulants that raise your blood pressure, such as nicotine, and eating foods rich in tyramine — an amino acid normally found in your body that helps regulate blood pressure — such as beer, wine and cheese. An episode of high blood pressure typically lasts 15 to 60 minutes and may occur several times a week.

Your adrenal glands are part of your endocrine system, which produces hormones that regulate processes throughout your body. Other parts of your endocrine system include:

• Pituitary gland
• Thyroid gland
• Parathyroid glands
• Pancreas
• Ovaries (in females)
• Testicles (in men)

Your adrenal glands are located on top of your kidneys. Each gland is about the size of the end of your thumb and is shaped like a boomerang. The adrenal gland consists of an inner core (medulla) and an outer layer (cortex). The medulla produces hormones called catecholamines. The most important of these are adrenaline (epinephrine) and noradrenaline (norepinephrine). Your body needs these hormones to maintain blood pressure and to help cope with stressful situations. Physical and emotional stresses usually trigger their release. When secreted into your bloodstream, catecholamines increase your heart rate and blood pressure and affect several other body functions.

Just what causes cells within the adrenal gland to develop into a tumor isn't clear. A pheochromocytoma begins in special cells called chromaffin cells, which are found in the core of the adrenal gland.

Pheochromocytomas usually affect only one adrenal gland. However, you may have more than one tumor in an adrenal gland or you may develop tumors in both adrenal glands. Because chromaffin cells are also located in nerve tissue throughout your body, sometimes pheochromocytomas arise outside of the adrenal glands (paraganglioma). Common locations for paraganglioma include the heart, bladder, back wall of the abdomen and along the spine.

About two in 10 pheochromocytomas runs in families or is associated with an inherited condition, such as:

• Multiple endocrine neoplasia, type II (MEN-II). In addition to a pheochromocytoma, people with MEN-II also have thyroid cancer. Other forms of MEN-II include pheochromocytoma with thyroid cancer and hyperparathyroidism (MEN-IIA), and pheochromocytoma with thyroid cancer and tumors of nerves in the lips, mouth, eyes and digestive tract (MEN-IIB).
• Von Hippel-Lindau (VHL) disease. People with this rare multisystem disorder are at high risk of pheochromocytoma, kidney cancer, and brain and eye tumors.
• Neurofibromatosis 1 (NF1). Pheochromocytomas can occur in a small percentage of people with NF1, a syndrome that includes multiple tumors in the skin (neurofibromas), pigmented skin spots, tumors of the optic nerve of the eye, and bone lesions.

Most pheochromocytomas are noncancerous (benign) and don't spread to other parts of the body. However, cancerous (malignant) pheochromocytomas can spread throughout the body, often to the brain, lungs or bone.

Pheochromocytomas are rare. They cause high blood pressure in less than 1 percent of people who have high blood pressure. However, it's important to detect and treat pheochromocytoma to prevent serious complications. See your doctor if you:

• Experience severe increase in blood pressure (hypertensive crisis)
• Have difficulty controlling high blood pressure
• Take more than four medications for high blood pressure
• Experience any signs and symptoms of a pheochromocytoma
• Have a family history of pheochromocytoma, multiple endocrine neoplasia type II (MEN-II), Von Hippel-Lindau disease or neurofibromatosis 1 (NF1)

Genetic mutations may be responsible for pheochromocytoma and paraganglioma, and your doctor may suggest genetic testing. However, whether you need genetic testing and, if so, what type depends on the location of your tumor and related medical conditions. If you have a history of pheochromocytoma or an associated disease, seek genetic counseling before undergoing genetic testing.

Your doctor will likely conduct a number of tests to determine if a pheochromocytoma is the cause of your signs and symptoms. These may include:

• Blood and urine tests. These are used to reveal elevated levels of the hormones adrenaline (epinephrine) or noradrenaline (norepinephrine) or their breakdown products (metanephrines). If the results of these tests suggest a pheochromocytoma, the next step is to determine the location of the tumor.
• Scans. A computerized tomography (CT) scan of the abdomen can detect the tumor in most cases. However, it may be necessary to scan other areas of the body, such as the neck, chest and pelvis. Scanning with other diagnostic imaging techniques, such as magnetic resonance imaging (MRI) or an m-iodobenzylguanidine (MIBG) scan, may be done to detect the tumor.

Many adrenal gland tumors are discovered incidentally during imaging studies conducted for other reasons. For example, you might see your doctor because of abdominal pain, and a CT scan may reveal a mass on one of your adrenal glands. A small percentage of adrenal gland tumors found incidentally are pheochromocytomas, even when no signs or symptoms are present. The vast number of adrenal gland tumors are noncancerous (benign) and nonfunctioning, requiring only observation and no treatment.

If you have high blood pressure caused by a pheochromocytoma, excessive force on your artery walls can seriously damage many of your body's vital organs. The higher your blood pressure or the longer it goes uncontrolled, the greater the damage. Untreated high blood pressure may lead to heart attack, heart failure, stroke, kidney failure, dementia, visual impairment and premature death. Having high blood pressure may also lessen your ability to think, remember and learn as you age. Uncontrolled high blood pressure has also been linked to cognitive decline and dementia.

A severe increase in blood pressure (hypertensive crisis) as high as 250/150 millimeters of mercury may occur with sudden release of a large amount of adrenaline hormones from the tumor. This can lead to life-threatening conditions, such as stroke or abnormal heart rhythm (heart arrhythmia). Long-term exposure to these hormones can cause damage to your heart muscle and lead to congestive heart failure. Excessive adrenaline hormones can also increase your risk of diabetes.

A pheochromocytoma is one of the few causes of high blood pressure that can be cured. Your doctor may prescribe medications that lower blood pressure. However, the best treatment for most pheochromocytomas is surgery to remove the tumor.

Medications

• Alpha blockers. Alpha blockers, also called alpha-adrenergic blocking agents or alpha-adrenergic antagonists, relax certain muscles and help small blood vessels remain open. They work by keeping the hormone noradrenaline (norepinephrine) from stimulating the muscles in the walls of smaller arteries and veins. This stimulation makes the vessel walls constrict. Blocking that effect causes the vessels to remain open and relaxed. This improves blood flow and lowers blood pressure. Examples of alpha blockers include phenoxybenzamine (Dibenzyline), doxazosin (Cardura), prazosin (Minipress) and terazosin (Hytrin).
• Beta blockers. Beta blockers, also known as beta-adrenergic blocking agents, make the heart beat more slowly and with less force. They work by blocking the effects of the hormone norepinephrine. This action slows down the nerve impulses that travel through the heart. Consequently, the heart doesn't pump as hard because it needs less oxygen and blood. Beta blockers also slow down the release of the enzyme renin from the kidneys, helping keep blood vessels dilated. Examples of beta blockers include atenolol (Tenormin), carvedilol (Coreg), metoprolol (Lopressor, Toprol XL) and (Inderal, Inderal LA).

For a pheochromocytoma, alpha blockers are used first to return your blood pressure back to within normal limits. Once your blood pressure is lowered, beta blockers can help control a rapid or irregular heartbeat. Both alpha and beta blockers are used in preparation for surgery.

Surgery
The most common treatment for a pheochromocytoma is surgical removal of the entire affected adrenal gland. In most cases, signs and symptoms disappear. Blood pressure usually returns to normal within hours to a day following surgery. Before surgery, your doctor will prescribe medications to block the effects of the adrenal hormones and control blood pressure. If both adrenal glands are affected by pheochromocytoma and are surgically removed, you'll need to take medication to replace hormones once produced by these glands.

Depending on the size and location of the tumor, laparoscopic surgery may be performed. This type of surgery involves inserting instruments through several small incisions. This procedure may result in quicker recovery when compared with conventional surgery, which requires a larger incision. Laparoscopic surgery isn't for everyone, however. Talk to your doctor about this less invasive technique to see if it's an option for you.

Sometimes surgery isn't an option because of the way the tumor is growing or because the tumor has spread (metastasized) to other parts of the body. If a pheochromocytoma is cancerous (malignant), treatment may go beyond medication and surgery to include radiation, chemotherapy or destroying the function (ablation) of arteries that supply blood to the tumor.