pheochromocytoma

Question 1

what are S/S of pheochromocytoma?

Answer 1

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)

Question 2

how do you test for pheochromocytoma?

Answer 2

first line = free metanephrines in plasma

other tests: plasma catecholamines, urine vanillylmandelic acid / catecholamines / metanephrines

Question 3

how do you optimize patient pre-operatively?

Answer 3

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

Question 4

What drugs should be avoided in patient’s with pheochromocytoma?

Answer 4

• 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

Question 5

surgery continues and patient has increased in BP to 200/100, what do you do?

Answer 5

• 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

Question 6

post-op nurse says blood sugar is 58, why is that?

Answer 6

• 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

Question 7

what is the Bezold-Jarish reflex?

Answer 7

• stimulation of cardiac receptors by stretch, chemicals or drugs –> increased parasympathetic activity and inhibited sympathetic activity
• causes bradycardia, vasodilation, hypotension

Question 8

what are signs of autonomic neuropathy?

Answer 8

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

Question 9

what do you do if someone has a pneumothorax?

Answer 9

• needle thoracostomy: 14g needle in 2nd intercostal space mid-clavicular line
• chest tube in 4th or 5th intercostal space anterior to mid-axillary line

Question 10

how do you calculate BP of circle of willis if patient in a beach-chair position?

Answer 10

subtract 0.77mg from measured pressure for every 1cm gradient (10cm gradient –> subtract 7.7mm)