Adrenal Flashcards
What is another name for the adrenal glands?
The Suprarenal glands
What cells make catecholamines?
Chromaffin cells in the adrenal medulla
All catecholamines are derived from what substance?
Tyrosine
Name the four catecholamines?
- DOPA
- Dopamine
- Epinephrine
- Norepinephrine
T/F: Epinephrine is made only in the adrenal cortex?
False; made only in the adrenal medulla
How much epinephrine is made in comparison to norepinephrine?
80%=Epinephrine
20% =Norepinephrine
What causes the body to initiate fight or flight response?
Pain, fear, hemorrhage, cold, hypoglycemia, hypotension, heat, exercise, surgery
Which areas of the body have increased/decreased CO?
Increased CO to heart and skeletal muscle.
Decreased CO to kidneys, skin, and mucosa
Is respiration increased or decreased with fight/flight response?
increased
Epinephrine and norepinephrine both act on which adrenergic receptor to cause arterial vasoconstriction?
Alpha-1
Which has a stronger Beta-1 effect?
Epinephrine
What causes norepinephrine to convert to epinephrine?
Phenylethanolamine N-Methyltransferase (PNMT)
PNMT expression is regulated by what?
Glucocorticoids (which helps account for glucocorticoids role in affecting blood pressure.
Pheochromocytoma is a tumor typically caused by what to types of tissue?
- Adrenal medullary hyperplasia
2. Extra-adrenal chromaffin tissue
What are symptoms of pheochromocytoma?
Paroxysmal HTN, tachycardia, H/A, sweating, anxiety, tremor, glucose intolerance.
Which type of pheochromocytoma tumor is most common?
85-90% are solitary tumors localized to single adrenal gland (Usually right)
10% of tumors are extra-medullary (mostly in the abdomen).
How are pheochromocytomas diagnosed?
1st by symptoms, then 24hrs VMA levels, then imaging
What substance are both epinephrine and norepinephrine degraded into?
Urinary Vanillylmandelic acid
Patient with diagnosed pheochromocytoma must first be started on beta blockers to lower HR?
False; Alpha Adrengergic antagonists must be started 10-14 days prior to surgery to normalize BP, then beta blockade can be started.
What is the risk of beginning beta blockers before alpha blockers on pheochromocytoma patients?
Risk of unopposed alpha mediated vasoconstriction
What are intraoperative risks associated with poorly controlled pheochromocytoma?
Large BP fluctuations, MI, CHF, dysrrhythmias, and CVA
What medications should be avoided intraoperatively with pheochromocytomas
Histamine releasing agents, metoclopramide, and glucagon
What can be expected changes in VS after pheochromocytoma removal?
Hypotension
How long does it take for catecholamine levels to return to normal after removal of pheochromocytoma?
Several days after and 75% of patients are normotensive within 10 days postop
Why is adrenal medullary hyposecretion not a serious problem?
Because the SNS compensates for cardiovascular regulation and other regulatory hormones compensate for metabolic effects.