Pheochromocytoma- Carroll Flashcards
What amino acid are catecholamines synthesized from?
What determines which catecholamines are found in which tissue?
Tyrosine
Enzyme expression
PNMT is not found in sympathetic nerves, but is found in the adrenal gland. Therefore, the adrenals produce mostly epinephrine and the sympathetic nerves produce mostly norepinephrine.
What is pheochromocytoma?
In what two tissues are they found?
A neuroendocrine tumor that secretes large amounts of catecholamines
Adrenal medulla (chromaffine cells) or Sympathetic nerves (extra-adrenal ganglia)
What can the catecholamine profile of a pheochromocytoma tell you about the tumor?
What biochemical tests should be done to test for pheochromocytomas?
What imaging tests should be done?
Location can be suggested by which catecholamines are released.
24-hour urine catecholamines
Plasma free metanephrines
MIBG or somatostain scintigraphy
What are some symptoms that might be seen in a pheochromocytoma? (it’s a long list!)
- Tachycardia
- Tachyarrhythmia
- Angina pectoris
- Hypertension
- Impaired intestinal motility
- Carbohydrate intolerance
- Sweating
- Free fatty acids
- Urine retention
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How are pheochromocytomas treated?
Why is the order of treatment extremely important?
- Give alpha blockers (until normal or hypotensive)
- Give beta blockers
- hydrate the patient
- surgically remove the tumor
Alpha blockers must be given to decrease blood pressure before beta-blockers to prevent hypertensive crisis. The patient must be medicated and hydrated before surgery because it is possible for catecholamine storms to occur during removal.
