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Wednesday, March 16, 2011

Pheochromocytoma

Pheochromocytoma is a tumour of the adrenal gland. The tumour is generally a benign one. These tumours produce excess of hormones like adrenaline. They are very vascular. A patient may also have a special nuclear medicine scan. A CT scan, an x-ray that uses a computer to make a picture of the inside of a part of the body or an MRI scan, which uses magnetic waves to make a picture of the abdomen, may also be done. Most of the time, a pheochromocytoma is noncancerous (benign), and treatment can return blood pressure to normal. A pheochromocytoma can develop at any age, but most commonly occurs in people between ages 40 and 60. Basically, these cells secrete too much epinephrine, norepinephrine and dopamine, and that causes the clinical signs and symptoms we will discuss below. Pheochromocytomas may also develop in people who have von Hippel-Lindau disease and in those who have neurofibromatosis (von Recklinghausen's disease).
Pheochromocytoma is a tumor of the adrenal gland that causes excess release of epinephrine and norepinephrine, hormones that regulate heart rate and blood pressure. Because of excessive catecholamine secretion, pheochromocytomas may precipitate life-threatening hypertension or cardiac arrhythmias. 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. Pheochromocytomas often cause the adrenal glands to make too many hormones called catecholamines. The extra catecholamines cause high blood pressure (hypertension), which can cause headaches, sweating, pounding of the heart, pain in the chest, and a feeling of anxiety. Some people who develop pheochromocytomas have a rare inherited condition, called multiple endocrine neoplasia, that makes them prone to tumors in the thyroid, parathyroid, and adrenal glands (see Multiple Endocrine Neoplasia Syndromes ). They are responsible in part for that feeling of an “ad-renal-ine” rush you feel when you are afraid. It is these cells that are involved in a pheochromocytoma.
Pheochromocytoma is a rare catecholamine-secreting tumor derived from chromaffin cells. If the diagnosis of a pheochromocytoma is overlooked, the consequences could be disastrous, even fatal; however, if a pheochromocytoma is found, it is potentially curable. pheochromocytoma (fe-o-kro-mo-si-TOE-muh) is a rare tumor that develops in the core of an adrenal gland. A pheochromocytoma (also phaeochromocytoma , UK spelling) is a neuroendocrine tumor of the medulla of the adrenal glands originating in the chromaffin cells, which secretes excessive amounts of catecholamines , usually adrenaline and noradrenaline ( epinephrine and norepinephrine in the US). Cells in the adrenal glands make important hormones that help the body work properly. Usually pheochromocytoma affects only one adrenal gland. They are complex endocrine ( hormone secreting) glands. Depending on which area you focus on inside them, you find cells that do different things. There is an area where the cells secrete cortisol , a hormone similar to cortisone. A pheochromocytoma may be life-threatening if unrecognized or untreated.

Causes of Pheochromocytoma

The common Causes of Pheochromocytoma :
  • Dopamine antagonists
  • People with this rare multisystem disorder are at high risk of pheochromocytoma, kidney cancer, and brain and eye tumors.
  • Others occur randomly, or are a symptom of other syndromes as mentioned above.
  • Cold medications
  • Radiographic contrast media
  • 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
  • Drugs that inhibit catecholamine reuptake, such as tricyclic antidepressants and cocaine

Symptoms of Pheochromocytoma

Some common Symptoms of Pheochromocytoma :
  • Headaches
  • Palpitations
  • Nausea
  • Rapid heart rate
  • Changes in body position
  • Abdominal pain
  • Sweating
  • Vomiting
  • Flushing
  • Weight loss
  • Chest pain
  • Excessive sweating
  • Irregular heartbeat (palpitations)

Treatment of Pheochromocytoma

Here is the list of the methods for treating Pheochromocytoma :
  • The definitive treatment is removal of the tumor by surgery.
  • Start alpha blockade with phenoxybenzamine 7-10 days preoperatively to allow for expansion of blood volume.
  • After surgery, it is necessary to continually monitor all vital signs in an intensive care unit in the case of an inoperable tumor, management with medication is necessary. Radiation therapy or chemotherapy have not been effective in curing this kind of tumor.
  • Prior to surgical removal, the high blood pressure will need to be brought under control, using first the medication phenoxybenzamine, followed by beta-blocking antihypertensive agents.
  • Use an arterial line, cardiac monitor, and Swan-Ganz catheter administer stress-dose steroids if bilateral resection is planned.
  • 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.
  • Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells throughout the body.

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