Adrenal #2 Flashcards

1
Q

What is a pheochromocytoma?

A
  • Catecholamine secreting tumor of the adrenal medulla
    • Originates in adrenal medulla and is related to tissues elsewhere in the body
    • >95% found in abdominal cavity
    • 90% originate in adrenal medulla
    • 10% involve both adrenal glands
    • functional tumors in multiple sites are present in 20% of patients, especially children
    • most common in young to mid adult
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2
Q

What are the predominant symptoms of pheochromocytoma?

the associated symptoms?

A
  • Predominant symptoms:
    • HTN- continuous or paroxysmal
    • HA
    • Diaphoresis/Pallor
    • Palpitations/tachycardia
  • Associated symptoms:
    • orthostatic hypotension
    • anxiety
    • tremor
    • chest pain
    • epigastric pain
    • flushing
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3
Q

What is the duration and frequency of pheochromocytoma episodes?

A
  • Duration- one hour or less
  • frequency- daily to once every few months
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4
Q

How is Pheochromocytoma diagnosed?

A
  • Urine tests- useful for screening but unreliable for definitive diagnosis
  • Plasma levels
    • reliably reflects the presence of Pheo
    • done by measuring the amount of free plasma metanephrines
      • Normatanephrine >400 pg/ml (metabolite of NE)
      • Metanephrine >220 pg/ml (metabolite of Epi)
  • CT/MRI to locate tumor
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5
Q

How is pheochromocytoma treated?

A
  • Surgical excision
  • VERY difficult to manage in the OR
    • restore intravascular volume pre-op
    • phenoxybenzamine (alpha 1&2 block- longer acting) or Prazosin (alpha 1 block- shorter acting)
      • restore release of insulin with alpha block
      • may go right up to day of surgery, may stop a few days before–depending on provider
    • Beta block (esmolol) if persistant tachy occurs
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6
Q

In a pt with pheochromocytoma, do you Beta block or Alpha block first?

A
  • Alpha block first
  • If you BB first, the decrease HR and contractility will make it impossible for the heart to pump blood agains the constricted smooth muscle vasculature
    • unable to maintain CO
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7
Q

What can be optimized/worked up in a patient with pheochromocytoma?

A
  • Cardiac work up- increased PVR can lead to myocardial ischemia, ventricular hypertrophy, CHF, cardiomyopathy
  • Hyperglycemia- will have decreased circulating insulin with increased glycogenolysis
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8
Q

What are the pre-op criteria for a pt with pheochromocytoma?

A
  • BP < 165/90 for 48 hours prior to surgery
  • BP upon standing should not be <80/45
  • ECG should have no ST-T wave changes unless they are permanent
  • No more than 1 PVC q 5 minutes
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9
Q

What are anesthetic considerations for a pateitn with pheochromocytoma?

A
  • Must have good communication with the surgeon
    • must be warned if they are about to manipulate the tumor
  • Continue adrenergic blockade
    • be prepared for hypo OR hypertension
  • Fluid management
    • prehydrate to prevent hypovolemia
    • May have a falsely elevated HCT, get a type and cross
    • Assess renal function
    • Have a fluid replacement plan!
      • BIG iv! At least 2!
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10
Q

What medications/anesthetic technique would you use for a pt with pheochromocytoma?

A
  • Heavy premedication with benzos and opioids
  • Anesthetic:
    • combined GA/continuous lumbar epidural
      • O2/air/Sevo or Des
      • 1.5-2 MAC
      • muscle relaxant: Vec or Roc
    • Epidural prior to induction
    • Invasive monitoring: Aline, CVL, Swan if there is extensive cardiac effects
  • Prepare for hyperdynamic BP
    • lidocaine- 1-2 mg/kg
    • Opioid (avoid histamine!)
      • sufentanil 0.5-1 mcg/kg
      • Fentanyl 3-5 mcg/kg
    • Propofol 3 mg/kg
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11
Q

What do you need to prevent during induction of a patient with pheochromocytoma?

What drugs should you have ready, in line, with the pump already programmed?

A
  • SNS response to DVL
    • Licocaine 1-2 mg/kg
    • Fantanyl 100-200 mcg or Sufentanil 10-20 mcg
  • Ready drugs:
    • Nitroprusside 1-2 mcg/kg
    • Phentolamine
    • Esmolol
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12
Q

How can BP be controlled in Pheochromocytoma?

HR?

A
  • BP:
    • Nitroprusside (preferred)
    • Phentolamine- tachyphylaxis, tachycardia and longer duration
    • Magnesium sulfate- inhibits catecholamine release from adrenal medulla
    • CCB
  • HR
    • Esmolol (preferred)
    • Labetalol
    • Metoprolo
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13
Q

What should you expect to happen as the surgeon is ligating the tumor’s venous drainage?

A
  • decrease release of catechols–prepare for hypotension
    • stopy antihypertensives
    • decrease concentration of VA
    • Give volume first!
    • administer pressors
      • phenylephrine
      • NE
      • Dopamine
  • *persistant hypotension may require an infusion of NE until the vasculature can adapt to decreased levels of alpha stimulation
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14
Q

What drugs should be avoided in a pt with pheochromocytoma?

A
  • Histamine releasers: Morphine, meperidine, atracurium
  • Halothane- sensitizes myocardium to epi
  • succinylcholine- fasciculations of abdominal muscles may cause release of catecholes from tumor
  • Pancuronium
  • atropine
  • metoclopramide- causes catechol release?
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15
Q

What are the post operative considerations for a patient with pheochromocytoma?

A
  • Analgesia
  • 50% of patients will remain hypertensive
    • elevated catecholamine levels for 10 days postoperatively
    • continue antihypertensive therapy
  • Usually can extubate early- young with no lung problems
  • hypoglycemia from excess insulin release and ineffective lipolysis and glycogenolysis
  • Steroid supplementation- for bilateral adrenalectomies or hypoadrenalism
  • postoperative HTN
    • presence of occult tumors
    • volume overload
    • continue monitoring
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