Pheochromocytoma


Pheochromocytoma

Description, Causes and Risk Factors:

A functional chromaffinoma, usually benign, derived from adrenal medullary tissue cells and characterized by the secretion of catecholamines, resulting in hypertension, which may be paroxysmal and associated with attacks of palpitation, headache, nausea, dyspnea, anxiety, pallor, and profuse sweating.

An adrenal gland is a small, orange gland. There are two adrenal glands in the human body: one on top of each kidney.

The center of the adrenal gland is called the “medulla.” The outer part of the gland is called the “cortex.” The medulla makes adrenaline (and adrenaline-like chemicals called catecholamines). The body needs adrenaline to maintain blood pressure and to help cope with stressful situations.

Researchers don't know exactly what causes cells within the adrenal gland to develop into a tumor. What they do know is that pheochromocytomas begin in special cells called chromaffin cells, which are found in the core of the adrenal gland. Your adrenal glands are part of your endocrine system, which produces hormones that regulate processes throughout your body.

The role of hormones: Your adrenal glands are located on top of your kidneys, and they produce hormones, including 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.

Multiple tumors possible: 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 also are situated in nerve tissue throughout your body, pheochromocytomas occasionally arise outside of the adrenal glands (paraganglioma). Common locations for paraganglioma include the heart, neck, bladder, back wall of the abdomen and along the spine.

Causes of hypertensive crisis associated with pheochromocytoma: An attack of high blood pressure (hypertensive crisis) associated with pheochromocytoma typically lasts less than an hour. Blood pressure may be normal or elevated between the episodic symptoms.

Symptoms:

Symptoms include headache (usuallysevere), excessive sweating, generalizedracing of the heart (tachycardia, palpitations), anxiety/panic attacks, nervousshaking, tremors, nausea, vomiting,weight loss, pain in the lower chestand upper abdomen, weakness, fever,heat intolerance, sugar intolerance, andsometimes low blood pressure whenstanding up.

Symptoms occur in discrete attacks at unpredictable intervals and usually last 15 to 20 minutes. The attacks may increase in frequency, length, and severity as the tumor grows. High blood pressure may occur only from time to time.

Diagnosis:

Reliable levels of adrenal hormones(adrenaline and noradrenaline) and theirbreakdown products (metanephrines)through blood or urine can usually helpyour doctor make a diagnosis.

There are three ways your doctor can dothis: blood tests, urine tests, and x-raytests such as computed tomography(CT), magnetic resonance imaging (MRI),and metaiodobenzylguanidine (MIBG or mIBG)scintigraphy.

Tests may include:

Blood tests: Special blood tests for pheochromocytomas measure how much adrenaline ornoradrenaline and their breakdown products (metanephrines) are in the blood orurine. Further tests include the glucagons stimulation test and clonidine suppression test.

Glucagon stimulation test: Because glucagon causes patients withpheochromocytomas to have symptomsof the disorder, this test is used forpatients who have occasional signs andsymptoms. Blood samples are drawn atspecific times to measure adrenaline andnoradrenaline levels. During this test,glucagon is injected into a vein whileblood pressure and heart rate are monitored. This test takes about 30 minutes.

Clonidine suppression test: The clonidine suppression test alsoinvolves measuring adrenaline andnoradrenaline as well as metanephrinesin the blood over time. Clonidine normallylowers blood levels of catecholamines,but if a tumor is present, catecholaminelevels do not decrease when clonidine isgiven. For this test, patients are asked toswallow a tablet of clonidine, and overthe next 3 hours, blood samples aretaken. Blood pressure and heart rate arechecked during this time period.

Treatment:

Pheochromocytoma can be treated by medications that lower blood pressure and/or surgery to remove the tumor.

The most common treatment for a pheochromocytoma is surgical removal of the entire affected adrenal gland. In most cases, signs and symptoms then disappear. Blood pressure usually returns to normal soon after 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 will need to take medication to replace the other hormones once produced by these glands.

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

Surgery may not be possible: Sometimes surgery is not an option because of the way the tumor is growing or because the tumor has spread (metastasized) to other parts of your 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.

High blood pressure may continue in about 1 in 4 patients after surgery. However, standard treatments can usually control high blood pressure. In about 1 in 10 people, the tumor may return. Patients who have been successfully treated for pheochromocytoma should have testing from time to time to make sure the tumor has not returned. Close family members may also benefit from testing, depending on the exact type of tumor.

NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.

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