pheochromocytoma Flashcards

1
Q

what are S/S of pheochromocytoma?

A

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)

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2
Q

how do you test for pheochromocytoma?

A

first line = free metanephrines in plasma

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

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3
Q

how do you optimize patient pre-operatively?

A

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
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4
Q

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

A
  • 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
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5
Q

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

A
  • 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
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6
Q

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

A
  • 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
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7
Q

what is the Bezold-Jarish reflex?

A
  • stimulation of cardiac receptors by stretch, chemicals or drugs –> increased parasympathetic activity and inhibited sympathetic activity
  • causes bradycardia, vasodilation, hypotension
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8
Q

what are signs of autonomic neuropathy?

A
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
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9
Q

what do you do if someone has a pneumothorax?

A
  • needle thoracostomy: 14g needle in 2nd intercostal space mid-clavicular line
  • chest tube in 4th or 5th intercostal space anterior to mid-axillary line
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10
Q

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

A

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

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