pheochromocytoma Flashcards
signs and symptoms of pheo
paroxysmal HTN, sweating, nausea, vomiting, pallow, orthostatic hypotension, HAs, palpatations
pheo and the heart
catecholamine induced cardiomyopathy or CHF 2/2 to sustained HTN can occur
additionally pheo is related to what in other systems of body
stroke, MI, sugar intolerance, ARF
diagnosing pheo tests
free metanephrines in the plasma is most reliable
plasma catecholamines, plasma chromagrin A, total urinary catecholamines, urinary metaneprhines, urinary VMA
what is the clonidine suppression test
can help diagnose pheo
in pts without pheo clonidine will lower plasma catecholamines in pts with HTN but not with pheo
what evaluation would you want prior to surgery
EKG: look for LVH
CXR to look for cardiomegaly or COPD (smoker)
echo (due to decreased energy)
CBC for potential anemia
alpha blockade and beta blockade if needed
what is the optimal duration of a blockade prior to surgery
10-14 days
some docs like to DC 24-48 hours prior to surgery, others continue it
some give half dose morning of
how does a-methylparatyrosine work
inhibits tyrosine hydroxylase (RLS enzyme) of catecholamine synthesis pathway
limited to pts with metastatic disease and requiring long term therapy (not surgical candidtate)
AEs: anxiety, diarrhea, sedation, extrapyramidal side effects crystaluria
factors that stimulate catecholamine release
fear, stress, pain, shivering, hypoxia, hypercarbia
mor
drugs that can potentially exacerbate catecholamine release
morphine and atracurium (histamine)
atropine, pancuronium, sux (vagolytic or sympathomimetic drugs that can stimulate the sympathetic nervous system)
what would be the best drugs to treat intraop HTN
nitroprusside
labetalol would be good for predominanlty epinephrine secreting tumors
MgSO4 inhibits catecholamine release, is direct vasodilator and antidysrhythmic but suboptimal in controlling HTN during tumor mainuplation
best drug to use for dysrhythmias
these dysrhytmias are usually __ in origin
ventricular in origin
lidocaine or b blocker, specifically esmolol
amiodarone can be used if needed with SVT from hypercatecholaminemia
what should be done prior to tumor vein ligation
volume expansion with LR or NS to prevent precipitous hypotension
vasopressors and inotropes are viewed as 2/2 modality bc won’t work as well with a blockade
decrease in catecholamine levels immediately following resection ___ levels increase and ___ may occur so may need ___
insulin levels increase, hypoglycemia, dextrose
