Endocrine (Altose): Adrenals and Pituitary Flashcards
What are two classes of hormones that the adrenal Cx releases?
Give one example of each (that we went over)
Mineralocorticoids (Aldosterone)
Glucocorticoids (Cortisol)
Describe the pathway of Aldosterone release.
Renin (kidney) –> Angiotensin I (liver) –> ACE lung –> Angiotensin II
Angiotensin II + serum K –> Aldosterone release (adrenal Cx)
What are the effects of aldosterone?
Save Sodium, Pee Potassium
(Na retention, K excretion)
What os Conn’s Syndrome?
Hyperaldosteronism due to adenoma
What are some symptoms of hyperaldosteronism?
HTN
HypoK metabolic alkalosis
Weakness
Fatigue
How can we treat hyperaldosteronism?
Treatment for Conn’s syndrome:
Replace potassium (0.5 mg/kg/hr central line; 4x slower in peripheral IV due to venal irritation)
Sx removal of adenoma
Note: If K > 2.8, cancel non-related elective case! (low serum potassium reflects much larger deficit since K is usally mostly sequestered in cells)
What are some symptoms of hypoaldosteronism?
HoTN, Severe hyperK, metabolic acidosis
How can we treat hypoaldosteronism?
Administer fludrocortisone
Describe the pathway to cortisol release.
CRF (hypothalamus) –> ACTH (ant pituitary) –> Cortisol (adrenal Cx)
CRF: corticotropin releasing factor
ACTH: adrenal corticotropic hormone
According to Dr. Altose, would a year of 5 mg prednisone overpower the body’s ability to make sufficient cortisol for surgical stress?
What is the threshold for stress dose administration with prednisone intake?
A year of 5 mg of prednisone should not overpower body’s adrenal gland’s ability to make sufficient cortisol even if taken over a year - this is because body produces 20 mg/day of cortisol normally and can produce up to 300 mg a day under stress.
HOWEVER, 20 mg of prednisone over 5 days can seriously impair the body’s ability to respond to surgical stress for up to 9-12 months (length of time to recover full adrenal cx function)!
What are the effects of cortisol on your body?
Increases blood glucose
Catabolic reactions (breakdown)
Anti-inflammatory
Anti-immune
Why does Cushing’s syndrome develop?
Develops due to chronic high levels of cortisol due to the intake of oral glucocorticoids/steroids.
What are some signs of Cushing’s syndrome?
Truncal obesity
Buffalo hump
Abdominal striae
Hyperglycemia
Osteopenia
HTN
Volume overload
Hypokalemic metabolic alkalosis (hyperaldosteronism)
Immunosuppression
PUD
Emotional changes
What is Addison’s diseases?
Disease state of adrenal insufficiency
How should we manage Cushing’s syndrome intraoperatively?
Manage HTN
Monitor volume status
Careful with bones
Watch for Addisonian crisis (acute adrenal insufficiency that can occur as a rebound)
What are some primary causes of adrenal insufficiency/Addison’s disease?
Idiopathic
Autoimmune
Infection
What are secondary causes of adrenal insufficiency?
HPA suppression
HypoACTH
What is our primary intra-op concern with adrenal insufficiency?
HoTN
How is Addison’s disease diagnosed?
Serum cortisol < 18 mcg/dL
Increase of < 9 mcg/dL after admin of 250 mcg ACTH
During acute stress, a normal pt’s plasma cortisol should be.. (#)
>22 mcg/dL
25 mg of cortisol is equivalent to how much hydrocortisone?
Prednisone?
Decadron?
Fludrocortisone?
20 mg Hydrocortisone
5 mg Prednisone
0.75 mg Decadron
2 mg Fludrocortisone (use to treat hypoaldosteronism)
What is the primary precursor for all catecholamines?
Tyrosine
What is the rate limiting step in catecholamine production?
Tyrosine hydroxylase
Tyrosine –> Tyrosine hydroxylase+Tyrosine –> DOPA
What are the roles of COMT and MAO?
Enzymes that breakdown catecholamines into metanephrine, nor-metanephrine, and vanillylmandelic acid
How is pheochromocytoma traditionally diagnosed?
Look for catecholaminergic breakdown products in the urine (metanephrine, normetanephrine, vanillylmandelic acid)
What are the symptoms of pheochromocytoma?
HTN
Palpitations
Tremor
Sweating
(Similar to MH and Thyroid Storm)
How do we pre-operatively manage a pt that has pheochromocytoma?
Alpha block first (phentolamine, phenoxybenzamine, prazosin)
Beta block second
When managing a pt with pheochromocytoma, why must we give alpha blockers before beta blockers?
Beta blockers decrease CO via negative inotropy, etc..
Alpha blocks will drop BP
Drop in BP may be too much for the beta-blocked heart to handle, which may result in heart failure.
This is why we drop BP / alpha block first, so that we can titrate in beta blockers to the point where CO is still maintained.
What pressors should we avoid, if we can, in pts with pheochromocytoma?
Ephedrine (due to its indirect mechanism of action, it’s difficult to maintain tighter control of Norepi levels)
What is the goal of pre-op preparation for a pt with pheochromocytoma?
BP management
Volume expansion
This can take ~2 weeks
In patients with pheo, what are some intra-op considerations? (monitors, drugs)
A-lines
CVP (potential for big boluses and infusions)
Avoid halothane (increases epi, may cause arrhythmias)
Phenylephrine > ephedrine for HoTN
NTG, SNP, nicardipine, Ca-channel blockers for HTN
Avoid histamine release
What are post-op complications after removal of an adrenal mass for a pheochromocytoma pt?
Rebound HoTN
Renal injury (surgical site close to kidney)
Residual tumor
Rebound hypoglycemia (lots of epi = hyperglycemia)
What is the first line treatment for cocaine toxicity?
Benzodiazapenes (like Ativan)
What structure regulates/stimulates the pituitary gland to release its hormones?
Hypothalamus
What hormones are released by the anterior pituitary gland? The posterior pituitary gland?
Anterior: Prolactin, GH, FSH, LH, TSH, ACTH
Posterior: Vasopressin/ADH, Oxytocin
What is the most common reason for patients to undergo a trans-sphenoidal resection of pituitary tumor?
Often due to an adenoma
What are some common symptoms of pituitary tumors/adenomas?
Headaches
Visual problems (pituitary sits on top of optic chiasm)
Other than pituitary adenoma, what are some other commonly seen pituitary diseases?
Acromegaly (excess release of GH)
DI (diabetes insipidis)
SIADH (syndrome of inappropriate ADH)
What is acromegaly caused by?
What are some anesthetic considerations to keep in mind with these patients?
Usually caused by excess GH secretion (Growth Hormone)
Usually accompanied by HTN and DM
Anticipate difficult airway
Veins and arteries may be enlarged (do Allen’s test if A-line will be used)
What is SIADH characerized by?
What are common causes of SIADH?
SIADH is characterized by excess release of ADH. This will lead to hyponatremia due to serum dilution from water retention
Common causes: head injuries, tumors, small cell carcinoma of lungs
What causes Diabetes Insipidus? What is it characterized by?
DI causes: neurogenic (pituitary stops making it), nephrogenic (ADH stops working in the kidneys)
Characerized by hypernatremia and hypovolemia due to loss of water
How would you treat SIADH intra op?
Fluid restriction
Lasix
How would you treat DI intra op?
Replace losses of water
