pheochromocytoma Flashcards
what are S/S of pheochromocytoma?
excessive secretion of catecholamines (NE, epi, dopamine)
HTN (out of control)
diaphoresis
headache
tachycardia
orthostatic hypotension (2/2 vasoconstriction, volume depletion, impaired reflexes from receptor down-regulation)
how do you test for pheochromocytoma?
first line = free metanephrines in plasma
other tests: plasma catecholamines, urine vanillylmandelic acid / catecholamines / metanephrines
how do you optimize patient pre-operatively?
a-adrenergic blockade 7-10 days before surgery and normalize BP below 165/90 for at least 2 days
- give fluids (pts hypovolemic)
- initiate BB if needed (target HR 60 - 80)
- NEED ECHO –> causes catecholamine induced cardiomyopathy and CHF
What drugs should be avoided in patient’s with pheochromocytoma?
- succinylcholine
- histamine releasing drugs (morphine, atracurium, sux)
- drugs that increase sympathetic activity (atropine, pancuronium, ketamine, ephedrine)
- sensitize myocardium to catecholamines (halothane)
- avoid droperidol, metoclopramide, ephedrine – a/w HTN in pheochromocytoma
surgery continues and patient has increased in BP to 200/100, what do you do?
- verify BP, ask surgeon to stop manipulation, ensure adequate ventilation, etc..
- medications: sodium nitroprusside (potent direct vasodilator, fast on, short duration), phenolamine (a-blocker and direct vasodilator), nitroglycerine, esmolol, labetalol, MgSO4
post-op nurse says blood sugar is 58, why is that?
- plasma catecholamines cause increased release of insulin.
- fluid replacement after tumor removal should include dextrose-containing solutions
- closely monitor glucose post-op for at least 24hrs
what is the Bezold-Jarish reflex?
- stimulation of cardiac receptors by stretch, chemicals or drugs –> increased parasympathetic activity and inhibited sympathetic activity
- causes bradycardia, vasodilation, hypotension
what are signs of autonomic neuropathy?
patient's who have DM, HTN affects parasympathetic system first resting tachy GERD exercise intolerance early satiety, prolonged post-pradial fullness, bloating, postural hypotension, lack of sweating, silent MI, peripheral neuropathy
what do you do if someone has a pneumothorax?
- needle thoracostomy: 14g needle in 2nd intercostal space mid-clavicular line
- chest tube in 4th or 5th intercostal space anterior to mid-axillary line
how do you calculate BP of circle of willis if patient in a beach-chair position?
subtract 0.77mg from measured pressure for every 1cm gradient (10cm gradient –> subtract 7.7mm)