Why is metoclopramide contraindicated in pheochromocytoma?
Metoclopramide is contraindicated in patients with pheochromocytoma because the drug may cause a hypertensive crisis, probably due to release of catecholamines from the tumor. Such hypertensive crises may be controlled by phentolamine.
What drugs are contraindicated in pheochromocytoma?
Drugs that increase sympathetic tone such as ketamine, ephedrine, pancuronium, metoclopramide should not be used in patients with pheochromocytoma [22]. Histamine provoking drugs such as morphine and atracurium should also be avoided.
What do chromaffin cells release?
Chromaffin cells (CCs) of the adrenal gland and the sympathetic nervous system produce the catecholamines (epinephrine and norepinephrine; EPI and NE) needed to coordinate the bodily “fight-or-flight” response to fear, stress, exercise, or conflict.
Why is dopamine contraindicated in pheochromocytoma?
Dopamine (applies to dopamine) pheochromocytoma Major Potential Hazard, High plausibility. The use of dopamine is contraindicated in patients with pheochromocytoma. The catecholamine effects of dopamine may aggravate this condition.
Why are beta-blockers contraindicated in pheochromocytoma?
Beta-blockers must never be started prior to adequate alpha-blockade, since in the absence of beta-2-mediated vasodilation, profound unopposed alpha-mediated vasoconstriction may lead to hypertensive crisis or pulmonary edema.
What do chromaffin cells secrete?
Abstract. Chromaffin cells (CCs) of the adrenal gland and the sympathetic nervous system produce the catecholamines (epinephrine and norepinephrine; EPI and NE) needed to coordinate the bodily “fight-or-flight” response to fear, stress, exercise, or conflict.
Why are beta blockers not given in pheochromocytoma?
Beta blockers are not administered until adequate alpha blockade has been established, however, because unopposed alpha-adrenergic receptor stimulation can precipitate a hypertensive crisis.
What if a patient with pheochromocytoma is given a beta-blocker before alpha blocker?
What are chromaffin cells in adrenal gland?
A type of cell that makes neurohormones (chemicals that are made by nerve cells and used to send signals to other cells) and releases them into the blood. Chromaffin cells make epinephrine (adrenaline) and norepinephrine (noradrenaline). They are found in the adrenal glands or in groups of nerve cells called ganglia.
What is the function of the chromaffin cells in the adrenal medulla?
What do chromaffin cells secrete in adrenal medulla?
Is dopamine elevated in pheochromocytoma?
Introduction. ] report plasma or urinary dopamine and its metabolite (methoxytyramine) can be elevated in pheochromocytomas but are not routine for diagnostic purposes.
Why are beta blockers contraindicated in pheochromocytoma?
Why do you block alpha before beta in pheochromocytoma?
Alpha-adrenergic blockade, in particular, is required to control blood pressure and prevent a hypertensive crisis. High circulating catecholamine levels stimulate alpha receptors on blood vessels and cause vasoconstriction. Beta blockers are used if significant tachycardia occurs after alpha blockade.
Why beta-blocker is not given before alpha blocker in pheochromocytoma?
What is pheochromocytoma?
Pheochromocytoma is a tumor that arises from chromaffin cells present in the adrenal medulla or paraganglion cells. It named in this way as these tissues have a special reaction on the application of a chromium salt. Dr. Charles Mayo presented the first case of pheochromocytoma in 1937 with a clinical diagnosis and therapeutic surgical resection.
Is chromogranin A useful in the diagnosis of malignant pheochromocytoma?
Chromaffin granule transmitters such as chromogranin A and catecholamines have been used in the diagnosis of pheochromocytoma, but the diagnostic and prognostic value of chromogranin A have not been explored in malignant pheochromocytoma.
What is the role of metanephrines in the diagnosis of pheochromocytoma?
Because metanephrines are continuously produced and continuously leak from pheochromocytoma tumor cells, largely independent of catecholamine release, metanephrines have become the most optimal biochemical test in the diagnosis of this tumor ( 85 ).
How does Dr House diagnose the patient with pheochromocytoma?
Although the patient has a violent history of homicide, Dr. House suspects that his episodic rage and aggression may be caused by an adrenaline secreting tumor. Dr. House is able to locate the tumor and diagnoses the patient with pheochromocytoma.