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Acute Care II > Pheochromocytoma > Flashcards

Pheochromocytoma Flashcards

1
Q

Epinephrine
Synthesized and stored where?
what % of catecholamine released by the adrenal medula?

A

adrenal medulla
80%

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2
Q

Norepinephrine
Synthesized & stored where?

A

adrenal medulla and peripheral sympathetic nerves

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3
Q

Dopamine
Precursor for what?
stored where?
used as a neurotransmitter where?

A

Norepinephrine
adrenal medulla & peripheral sympathetic nerves
CNS

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4
Q

The biologic 1/2 life of catecholamines is what?

A

10-100 seconds

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5
Q

Concentrations vary d/t loose association with what?

A

albumin

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6
Q

Eliminated from circulation via what routes?
What is the most common?

A

reuptake by sympathetic nerve endings (most common)
Metabolized
Conjugated
renally excreted

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7
Q

Catecholamines affect what?

Actions are mediated by what?

A

HR
BP
contractility
conduction velocity

adrenergic receptors

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8
Q

Alpha 1 receptors mediate what?

A

vascular & smooth muscle contraction
stimulation = vasoconstriction and increased BP

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9
Q

Alpha 2 receptors mediate what?

A

the inhibition of NE release

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10
Q

Beta 1 receptor stimulation leads to what effects?

A

+ Inotropy
+ Chronotropy
Increased renin secretion from kidneys
Lipolysis in fat cells
bronchodilation
vasodilation in skeletal muscle
glycogenolysis
Increased NE release from sympathetic nerve endings

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11
Q

Beta 2 receptor stimulation leads to what effects?

A

Smooth muscle relaxation
Bronchodilation
Hepatic glycogenolysis
pancreatic release of glucagon

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12
Q

Beta 3 receptor stimulation leads to what effects?

A

regulates lipolysis & energy expenditure

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13
Q

Dopamine 1 (DA1) receptor are located where?
Stimulation leads to what?

A

Cerebral, coronary, mesenteric, & renal beds
vasodilation

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14
Q

Dopamine 2 (DA2) receptors are located where?
Stimulation leads to what effects?

A

presynaptic & localized to sympathetic nerve endings, sympathetic ganglia, & the brain
inhibition of NE

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15
Q

Types of Catecholamine secreting tumors from chromaffin cells

A

Pheochromocytoma (from adrenal medulla)
Extra-adrenal catecholamine-secreting paragangliomas (outside adrenal medulla)

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16
Q

Hereditary types of Pheochromocytomas
autosomal dominant
Constellation includes adrenal pheo, thyroid Ca, & hyperparathyroiidism

A

Multiple Endocrine Neoplasia (MEN) type 2a

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17
Q

Hereditary types of Pheochromocytomas
autosomal dominant
Pheo, thyroid Ca, mucosal neuromas, thick corneal nerves, intestinal ganglioneuromatosis, marfan features

A

Multiple Endocrine Neoplasia (MEN) type 2b

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18
Q

Hereditary types of Pheochromocytomas
Autoasomal dominant
neurofibromas, cafe au lait spots, freckling of axilla, inguinal areas, 2% develop adrenal pheo’s

A

Neurofibromatosis

19
Q

Clinical Manifestations
Result from?
May be spurred by?
“Spells” may occur at what frequency?
May be associated with?
May have what that can go unrecognized?

A

excess concentrations of catecholamines
anxiety, meds (reglan, anesthesia), postural change, exercise, increased abd. pressure
multiple times/day or q month & typically last 15-20 min
with co-secreted hormones (ACTH-Cushings, parathyroid hormone-hypercalcemia, vasopressin-SIADH, growth hormone-acromegaly)
cardiomyopathy & CHF

20
Q

“Spell” related clinical manifestations

A

HTN (chronic or episodic)
Anxiety
Diaphoresis
Epigastric/chest pain
Headache
N/V
Pallor
Palpitations
Tremor

21
Q

Chronic related clinical manifestations

A

Anxiet
Cold hands & feet
Constipation
Diaphoresis
Epigastric/chest pain
Fatigue
Fever
Retinopathy
Headache
Hyperglycemia
HTN
Pallor
Palpitations
Tremor
Wt. loss
Orthostatic hypotension

22
Q

Other disorders that could mimic Pheo include?

A

Idiopathic hypotension
Panic d/o
Withdrawal from adrenergic inhibitor (beta blocker)
Angina
Hyperthyroidism
Insulinoma
Menopause
PSVT
Pulmonary edema
Renovascular HTN
SAH

23
Q

Pheo should be suspected if the patient as 1 or more of the following

A

Severe, sudden, unexplained HTN
Hyperadrenergic spells
Resistant HTN
Family hx
Resected pheo with recurrent HTN or spells
Incidental adrenal mass
Early onset HTN (<20yrs)
Idiopathic Cardiomyopathy

24
Q

Physical Exam findings may include?

A

sustained/paroxysmal HTN
Generalized sweating
tachycardia
postural hypotension
Tremor
HTN retinopathy

25
Q

Labs to get for suspicion of pheo

A

Plasma metanephrine OR
24 hr urine for metanephrines

26
Q

24 hr urine for metanephrines positive results are

A

2.2mcg of total metanephrine/gm creatinine

135mcg total catecholamines/gm creatinine

27
Q

False (+) results are common, what can you do to confirm if you suspect a false positive?

A

Repeat sampling in supine position
Clonidine suppression test with measurement of plasma normetanephrine
Chromogranin & urinary fractionated metanephrines measurements

28
Q

Meds that may cause falsely elevated results include?

A

TCADs
levodopa
acetaminophen
cocaine
MAOIs
Amphetamines
buspar
labetalol

29
Q

What is the indication for a Clonidine Suppression test?

A

To discriminate patients with mildly elevated test results for plasma normetanephrine due to increased sympathetic activity from patients with elevated results due to a PPGL.

30
Q

What conditions must be met prior to a clonidine suppression test?

A

Withdraw sympatholytic drugs before testing (e.g. beta blocker) 48 hrs prior to testing
The test is carried out with patient in the supine position
The test is cancelled if baseline blood pressure is < 110/60 mmHg or in volume-depleted patients

31
Q

Clonidine Suppression Test procedure

A

A PIV is placed in the AC
After 20 min of supine rest, a first blood sample is drawn
Clonidine is administered 300 nanogram/70kg body weight
BP and HR are measured at regular intervals before and during the test
Three hours after drug administration a second blood sample is drawn
The tubes with blood samples must immediately be placed on ice
Blood samples are then analyzed for normetanephrines

32
Q

Interpretation of a Clonidine Suppression test

A

An abnormal test resulting in a PPGL includes an elevation of plasma normetanephrines at 3h after clonidine admin and a less than 40% decrease in levels compared with baseline

33
Q

When to get Imaging to confirm diagnosis?

A

obtain after labs

34
Q

1st line imaging is?

A

CT abdomen/pelvis

35
Q

MRI should be used for what?

A

metastatic PPGLs
Skull base & neck paragangliomas
Surgical clips in place
allergy to CT contrast
when XRT should be limited

36
Q

PET CT in patients with what?

A

mets

37
Q

Genetic Testing
Decision should be made how?
How many different genes are linked to PPGL?
Use what to determine need for genetic testing?

A

Shared decision making
14
clinical feature-driven diagnostic algorithm to determine genetic testing

38
Q

Consider what as prompts for the need of genetic testing?

A

Younger age of presentation
family hx
multifocal PPGLs
BL adrenal tumors

39
Q

Management
Personalized approach includes?
Treatment of choice?

A

testing, imaging, surgery, f/u
Surgical resection

40
Q

Pre-op medications management

A

Utilize Alpha & beta blockers for pre-op BP control
Phenoxybenzamine (dibenzyline) 10 mg BID up to 1mg/kg/d (start 7-14 days prior to surgery)
start before beta blocker therapy to avoid unopposed alpha stimulation & HTN crisis

41
Q

Beta-blocker therapy to use for pre-op management

A

Propranolol 20 mg tid up to 40mg TID
after @ least 3-4d of alpha blocker
nonselective beta blocers (blocks 1&2)

OR

Atenolol 25 mg qd up to 50mg qd
cardioselective (beta 1)

42
Q

Follow up
monitoring in immediate post-op period includes?
Biochemical testing to document successful tumor removal when?
Check plasma or urine metanephrines how often after surgery? why?

A

BP, HR, glucose monitoring
2-4 wks
annually d/t reports of high rates of recurrence or mets after resection

43
Q

Expected Outcomes
Symptoms/HTN usually do what?
Requires what?
Survival rate if malignant?

A

resolve or improve w/ tx
lifelong monitoring
<50%

44
Q

Pregnancy
Pheo + pregnancy = ?
Mortality rate for mom? baby?
what should be given as soon as dx is made?
Tumor resection is ideally done when?
If unable to complete resection during optimal time what must happen?
Spontaneous what is likely?

A

bad prognosis
48%; 55%
dibenzyline
1st or 2nd trimester
3rd trimester resection followed by C section
abortion

Acute Care II (5 decks)

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