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)

Question 11

How long to have alpha blockade prior to surgery for pheochromocytoma?

Answer 11

10-14 days

Question 12

How does Alpha-methylparatyrosine work? In which patient with pheochromocytoma is it used?

Answer 12

Inhibits tyrosine hydroxylase, of the catecholamine synthetic pathway resulting in 40-80% reduction in catecholamine synthesis. Reserved for those with metastatic disease

Question 13

What drugs to avoid in pheochromocytoma?

Answer 13

Desflurane, Metoclopramide, Ketamine, Succinylcholine, morphine, Atracurium, aTROPINE, PANCUROINUM, EPHEDRINE, halothane, droperidolw