Adrenal #2

Question 1

What is a pheochromocytoma?

Answer 1

• 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

Question 2

What are the predominant symptoms of pheochromocytoma?

the associated symptoms?

Answer 2

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

Question 3

What is the duration and frequency of pheochromocytoma episodes?

Answer 3

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

Question 4

How is Pheochromocytoma diagnosed?

Answer 4

• 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

Question 5

How is pheochromocytoma treated?

Answer 5

• 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

Question 6

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

Answer 6

• 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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

• 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

Question 9

What are anesthetic considerations for a pateitn with pheochromocytoma?

Answer 9

• 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!

Question 10

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

Answer 10

• 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

Question 11

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?

Answer 11

• 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

Question 12

How can BP be controlled in Pheochromocytoma?

HR?

Answer 12

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

Question 13

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

Answer 13

• 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

Question 14

What drugs should be avoided in a pt with pheochromocytoma?

Answer 14

• 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?

Question 15

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

Answer 15

• 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