Pheochromocytoma, Splenic, Carcinoid, Blah Blah Flashcards
What is a pheochromocytoma?
Cathecholamine secreting tumor from the chromaffin cells of the adrenal system
What do chromaffin cells produce?
Epinephrine and norepinephrine
Can pheochromocytoma be cured?
HTN can be cured by resection
Pheo patient demographics
- Equal male and female
- Usually 30-50 years old
- 10% in children
What is familial pheo associated with?
- Can be a part of Multiple Endocrine Neoplastic (MEN) syndrome
- Almost 100% of MEN II pts have or will have a pheo
In what part of the adrenal gland are most pheos found?
80% in the adrenal medulla
Are pheos malignant or benign?
Can be either
What do pheos secrete?
- Can secrete norepinephrine and/or epinephrine
- Usually secrete norepi 85% and epi 15% (normal ratio reversed)
How does neurogenic control of pheos occur?
It usually doesn’t
Pheos secrete catecholamines without neurogenic control
Hallmark symptom of pheo
Hypertension
How often do patients have symptoms with a pheo?
Infrequently to several times daily (very unpredictable)
Usually last a few minutes to several hours
S/S of pheo depend on what they are secreting the most
What are the signs of norepinephrine secretion?
- Increased SBP
- Increased DBP
- Reflex bradycardia
S/S of pheo depend on what they are secreting the most
What are the signs of epinephrine secretion?
- Increased SBP
- Decreased DBP
- Tachycardia
Effects of pheo on SVR, CO and plasma volume
- Increased SVR
- Normal CO
- Slightly decreased plasma volume
EKG changes with pheo
- ST changes (increased or decreased)
- Flat/inverted T waves
- Prolonged QT
- Peaked P waves
- L axis deviation
- Dysrhythmias
Cardiomyopathy is common with pheo..
Which chamber usually?
LV
blood glucose in pheo patients (prior to resection)
Increased due to inhibited insulin release
How do you diagnose a pheo?
What is most sensitive?
24 hours metanephrines and catecholamines
Most sensitive is plasma free metanephrines
What are the two plasma free metanephrines?
Metanephrine and normetanephrine
What is normetanephrine?
What is considered elevated?
Norepinephrine metabolite
>400 pg/mL
What is metanephrine?
What is considered an elevated level?
Epinephrine metabolite
>220 pg/mL
test to perform if plasma free metanephrines questionable?
clonidine suppression test or glucagon stimulation test (if DBP <100)
imaging for a pheo
- CT
- MRI
- PET scan
What pheo test may be done in the cath lab?
Taking catecholamine samples from adrenal vein
Differential diagnoses of pheo
- MH
- Thyroid storm
- Carcinoid crisis
Where are catecholamines from pheos metabolized?
What is the significance?
Metabolized within chromaffin cells
plasma free metanephrines are more accurate for diagnosing pheo than plasma epi and norepi levels
T/F - mosty pheos secrete more epi than norepi
false - most pheos secrete norepi more than epi
Effects of alpha blockade treatment for pheo
- Decrease BP
- Increase volume
- Prevent HTN episodes
- Re-sensitize receptors
- Decrease myocardial dysfunction
Most common alpha blocker for pheo
MOA?
Phenoxybenzamine (Dibenzyline)
MOA: non competitive, non-selective irreversible a-blocker
adverse effect of alpha blocker overtreatment
How to avoid in pheo pts?
Orthostatic hypotension
D/C 24-48 hours pre-op to avoid refractory intra-op hypotension
Two shorter acting pure alpha-1 blockers
Benefits vs. phenoxybenzamine
- Prazosin (Minipress) and doxazosin (cardura)
- Benefits: less tachycardia, easier to titrate
How do you treat phenoxybenzamine induced tachycardia?
With non-selective B-blockade
- Usually Propanolol
- Also atenonol, metoprolol, labetalol
When treating pheo, do you want to block alpha or beta first?
Alpha
Why would you want to use EXTREME CAUTION with beta-blockade prior to alpha-blockade?
Beta blockade–> unopposed alpha effects –> vasoconstriction and HTN crisis
adjunct treatments for pre-op pheo
- Metyrosine
- Ca++ channel blockers
- ACE inhibitors
How does metyrosine treat a pheo?
Metyrosine is a tyrosine inhibitor so it blocks catecholamine synthesis
2 primary intra-op goals for a pheo
- Avoid catecholamine release (drugs, stimulation)
- Maintain CV stability with short-acting drugs
What occurs with ligation of tumor-related vessels with pheo intraop?
Significant hypotension
Monitoring intraop for pheo
- Standard monitoring
- Arterial line
- Conisder CVP, PA, and TEE also
T/F You want your patient slightly hypovolemic for pheo
FALSE
Avoid hypovolemia
Would cause catecholamine release? maybe
drugs to avoid in a pheo pt
- Morphine
- Atracurium
- Atropine
- Succinylcholine
- Pancuronium
- Ephedrine
- Ketamine
Most common approach for pheo excision
Disadvantages?
- Laparoscopic adrenalectomy
- Insufflation and tumor manipulation cause HTN
What is required for excision of large pheos?
Open excision
Name some times during surgery that we would cause increased catecholamine release with pheo
- Laryngoscopy
- Incision
- Light anesthesia
- Emergence
Is pre-op alpha blockade always effective for preventing hypertension?
Nope
SBP >200 is common intra-op regardless of pre-op alpha blockade
Drugs to have prepared for pheo patient?
“Have potent, rapid onset drugs prepared and ready”
- Nipride - drug of choice
- Phentolamine
- Nitroglycerine
- Labetalol
- Mag sulfate
- Esmolol
- Diltiazem
caution with using increased anesthetic depth to treat HTN with pheo
Increases risk of hypotension with venous ligation
What drugs should you have available for ventricular dysrhythmias with pheo?
- Lidocaine
- Beta-blockers (propanolol, esmolol)
How to prevent and treat hypotension associated with venous ligation of pheo
- Prevent: pre-treat with cyrstalloids
- Treat: pressors and inotropes if needed
T/F Cell saver is a good option for pheo patients to prevent hypotension with venous ligation
False
Cell-saver is high in catecholamines
What happens to blood sugar after resection of pheo?
How do you treat?
- Increased insulin and decreased glucose
- Begin dextrose solution after resection
When does hypertension resolve after pheo resection?
Most patients eventually become normotensive
- Approximately 50% with be hypertensive for several days
- 25% remain hypertensive for life
- ?? about the other 25%
How long does it take for plasma catecholamine levels to normalize?
(after pheo resection or what?)
7-10 days
This doesnt make sense because she said plasma catecholamine levels are not what you really look at but okkkkk - i think theyre still elevated just not the most accurate for diagnosing?
Most frequent post-op cause of death after pheo resection
How to treat? (if they havent died yet)
Hypotension due to sudden decrease in catecholamines with refractory vasodilation
Treat with increased fluids, pressors if necessary
