Pheochromocytoma - Causes, symptoms and treatment. MF.
Jun 09, 2018
Pheochromocytoma is a hormone-active tumor of adrenal medulla( more than 90% of all cases).This formation produces a large number of specific substances - catecholamines( adrenaline, norepinephrine).
Similar tumors in the histological structure can be observed outside the adrenal glands. Then the nodes of the sympathetic department of the autonomic nervous system can be considered as a source of pheochromocytoma. The localization of the tumor in this case can be different. Most often, neoplasms can be located in the abdominal and thoracic cavities, in the small pelvis, along the vessels of the head and neck.
Histological section of pheochromocytoma tissue
Pheochromocytoma can be considered a rare enough disease. The incidence rate is about 2-3 cases per 10 000 population. In adulthood women are more often sick, but in children - boys. Of all the diseased, up to 20% have a clear hereditary burden on the pheochromocytoma, including within the syndromes of multiple tumor cells of the diffuse endocrine system.
The role of catecholamines in the body
Adrenaline and norepinephrine are secreted in the human body all the time. Their concentration increases sharply after a load of any kind. Catecholamines are rightly called "stress hormones".Any active work, especially physical labor, contributes to the release of noradrenaline and adrenaline. The manifestation of such a reaction can be considered an increase in body temperature, increased heart rate, redistribution of blood flow.
Adrenaline is considered a hormone of "fear".Emission of adrenaline occurs with strong excitement, fear, strong physical activity. Adrenaline raises blood pressure, increases the utilization of carbohydrates and fats. The physiological response to stress under the influence of adrenaline is an increase in endurance.
Norepinephrine is the hormone of "fighting".Under its action, muscle power increases significantly, an aggressive reaction arises. Norepinephrine is produced by bleeding, physical exertion, stress. Excess formation of catecholamines is possible with chronic stress.
Symptoms of pheochromocytoma
Pheochromocytoma is the source of adrenaline and noradrenaline secretion in large doses. Symptoms of the tumor are associated with the action of these hormones. Develops hypertension, its crisis course, orthostatic hypotension, loss of body weight, impaired glucose tolerance. Some patients come with complications of arterial hypertension. For example, stroke, myocardial infarction, left ventricular failure, hypertensive damage to the vessels of the fundus.
Typical paroxysms with pheochromocytoma
In pheochromocytoma, arterial hypertension is of a crisis( paroxysmal) nature in 40-85% of cases. Typically, the presence of a constantly elevated level of pressure with the development of periodic crises in blood pressure. Arterial hypertension in crisis is accompanied by other signs of excess adrenaline and norepinephrine. Such signs can be sweating, pallor of the skin, urination with a large volume of urine, a tremor in the muscles, a violation of the heart rhythm, an increase in blood sugar. In the classical case pheochromocytoma is manifested by increased pressure, profuse sweating, and tachycardia. This combination has a high sensitivity( 91%) and specificity( 94%).During the crisis, cramps, headache, severe anxiety, panic, fear of death are possible.
Methods for diagnosis of pheochromocytoma
It is rather difficult to detect excess adrenaline and norepinephrine in the blood. These substances disintegrate within a few minutes after entering the blood.
Excessive secretion of catecholamines is confirmed by by determining the concentration of catecholamine exchange products in blood and urine .These substances are quite stable. The level of their content is significantly increased within a day after the paroxysm of hypertension. First of all, it is recommended to investigate the concentration of conjugated metanephrine and normetanephrine.
Sometimes the level of excretion of vanillmundalic acid is determined. This analysis is simpler, but its accuracy is not high. A number of drugs and food products distort the results of the survey.3-5 days before the analysis it is desirable to exclude from the supply of citrus fruits, nuts, beets, carrots, bananas, chocolate, vanillin.2 weeks before the test, it is necessary to abolish tricyclic antidepressants, reserpine, clonidine, analgin, paracetamol.
Currently conducting provocative tests is considered inexpedient.
After the increased production of catecholamines in the body is proven, the patient is given visualization methods to determine the location of the tumor. Pheochromocytomas are usually detected when performing computer or magnetic resonance imaging of the abdominal cavity of .
Sagittal Shot MRI of the abdominal cavity. Arrows show bilateral adrenocortical pheochromocytomas, in combination with carcinomas.
The ultrasound examination of the is less accurate. Difficulties in detecting neoplasms are associated with the intra-adrenal localization of the pheochromocytoma. It happens in 10% of all cases. To detect the focus, scintigraphy with methiodibenzylguanide( radioisotope study) can be used.
Treatment of pheochromocytoma
The main method of treating pheochromocytoma is surgical operation .Medications are used to prepare the patient for such an intervention. Preparation should take at least 6 weeks to eliminate dehydration and restore reduced plasma volume. Most often preoperative preparations use the alpha-blocker Phenoxybenzamine( 20 mg orally every 8 hours).Highly effective is selective alpha-1-adrenoceptor of long-acting doxazosin( 1-16 mg orally every 12-24 hours).
During the operation itself, for the normalization of pressure, drugs may be needed to increase and to lower the pressure. In consequence of anesthesia or damage to the tumor tissue, many catecholamines can enter the blood. To reduce pressure, sodium nitropurside and phentolamine( short-acting alpha antagonist) are used. After the operation, hypotension may develop. It may be necessary to replenish the volume of circulating blood.
Well-prepared patients rarely face such complications of surgery. The tumor is carefully examined by a histologist after the operation under a microscope. Single benign tumors occur in 50-70% of cases. The forecast in this case is favorable. Repeatedly occur pheochromocytomas only in 10-15% of patients.
In 10% of cases, tumor cells turn out to be malignant. In this case, additional monitoring and treatment is required from the oncologist. Foci of metastasis occur in 3-14% of cases. Usually metastases are detected in regional lymph nodes, hepatic tissue, bones, lungs and muscles. The prognosis for malignant tumors is not very favorable.44 of 100 patients die in the first 5 years after confirmation of the diagnosis. Metastases often grow slowly and are detected several years after the operative treatment of the pheochromacitoma itself. The effectiveness of radiation and chemotherapy for the treatment of metastases is small. The most common surgical removal of the focus of metastasis and the intake of methylthyrosine( a false precursor of catecholamines).Recently, the possibility of using modern targeting drugs in the case of a malignant pheochromacytoma is being considered.
Conservative treatment of with pheochromocytomas is performed in case of inability to perform operative treatment. Long-term therapy with the drug methylthyrosinome can disrupt the work of the gastrointestinal tract and the stability of mental processes.
Doctor of the endocrinologist Tsvetkova IG.