Скачать или смотреть Oral Boards: Pheochromocytoma

What is a pheochromocytoma?
It is a catecholamine-secreting tumor that is made up of chromaffin tissue, meaning it can grow anywhere chromaffin tissue is found. They are most commonly found in the adrenal medulla (80-90%) and occasionally extra-adrenal in the sympathetic paraganglia (10-20%). In all patients who present with hypertension, pheo’s account for 1 in 1000 patients.

Describe the adrenal gland.
There are two adrenal glands positioned superior to each kidney. There are two distinct zones: the cortex and the medulla. They shave separate embryologic origins and secrete different substrates. The adrenal medulla secretes catecholamines: epinephrine, norepinephrine, and dopamine. The cortex secrete various corticosteroids: mineralocorticoids, glucocorticoids, and sex hormones.

What are some clinical features of pheo’s?
The classic triad is severe headaches, diaphoresis, and palpitations. You can also see weight loss, stroke, new-onset diabetes, or acute renal failure.

What meds are taken before surgery?
Alpha-blockers are the mainstay for treatment, 1 to 3 weeks prior to surgery. These include phenoxybenzamine, terazosin, prazosin, and doxazosin. You can see reflexive tachycardia from these treatments which may require beta-blockade as well. However, you never want to have beta-blockade without alpha-blockade - this can lead to severe vasoconstriction. Calcium channel blockers are emerging as a potentially safer alternative to alpha-blockers.

What are potential postop concerns?
Postop hypotension should be treated with IV fluids and vasopressors like norepinephrine or vasopressin if needed. Occasionally you may notice your patient to be more somnolent from the abrupt removal of the catecholamine source. You can also see hypoglycemia chronically elevated insulin levels.

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