102 terms

Endocrinology - Adrenal Cortex and Adrenal Medulla

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What hormones are secreted by the adrenal glands?
Cortisol, aldosterone, and androgens, and catecholamines
What are the androgens?
DHEA, DHEAS, testosterone, and androstenedione
Which of the hormones are secreted from the inner medulla?
Which of the hormones is a glucocortoid hormone?
Which of the hormones is a mineralocorticoid?
What does CRH (Corticotropin-releasing hormone) stimulate?
ACTH synthesis, Beta lipotrophin, Beta endorphins
In what situations is ACTH secreted?
Major illness, surgery, injury, exercise, hypoglycemia, starvation
What inhibits ACTH via negative feedback?
What time of day is highest amount of ACTH secreted?
early AM (0400-0600) in pulses
What time of day is the lowest amount of ACTH secreted?
night time
What is stimulated by increase in ACTH?
increase in cortisol, aldosterone and melanin secretion
What time of day is the greatest amount of cortisol secreted?
At wakening
What time of day is the lowest amount of cortisol secreted?
at bedtime
How does cortisol elevates blood glucose level?
Inhibits insulin secretion, inhibits glucose uptake by muscle and fat, increases protein breakdown for amino acid conversion to glucose and increases hepatic gluconeogenesis
How does cortisol affect fat metabolism?
increase lipolysis and quantity of free fatty acids
What is the name of group of glands that regulate the secretion of cortisol and adrenal androgens?
Hypothalamic-Pituitary-Adrenal Axis (HPA axis)
Is ACTH or the renin-angiotensin system the primary regulator of aldosterone secretion?
Renin-Angiotensin system
When cortisol inhibits glucose from being uptaken by muscles, what give muscles the energy to move?
Free fatty acids as a result of increased lipolysis, which was stimulated by cortisol
What is the major reason cortisol is used pharmacologically?
suppression of the immune system and inflammation
What are some effects of increased cortisol level?
Weight gain/truncal obesity
Inflammation/Immune System is suppressed
Sodium and water retention
growth failure in children
altered mood, behavior, and cognition
Suppresses bone formation and decreases calcium absorption (Osteoporosis)
Catabolic effects on bone, connective tissue, and muscle (loss of connective tissue, thin skin, easy bruising, development of abdominal striae, impaired wound healing)
What is the most common cause of Cushing's syndrome?
Long term use of high dose exogenous glucocorticoids
Name the glucocorticoids name in lecture.
Prednisone, dexamethasone, hydrocortisone
What is the 2nd most common cause of hypercorticolism?
ACTH-producing pituitary tumor
Do patients with Cushing's continue to have a diurnal rhythm of cortisol secretion.
No. Cortisol levels are high day and night.
Signs and Symptoms of Cushing's.
weight gain/truncal obesity, moon face, weakness, hypertension, abdominal stretch marks, easy bruising, osteoporosis, hyperglycemia/diabetes, buffalo hump, women-hirsutism and amenorrhea
Why would a patient with Cushing's have weak muscles?
Protein is being broken down to be converted to glucose.
Why would a patient with Cushing's have HTN?
Cortisol stimulates aldosterone which retains sodium and water, increases blood volume, and thus the blood pressure
Why would women develop hirsutism and amenorrhea?
Polycystic ovaries due to excess adrenal androgen production
What screening tests would you order if you suspect Cushing's syndrome?
24 hour UFC, 24 hour creatinine levels
How close should the results of the 24 hour creatinine levels be to confirm completeness of the urine collections?
within 10% of each other
What is the normal average level for 24 hour cortisol?
<55 mcg/24 h
What would be DDx of patient presenting with excess cortisol with an elevated ACTH level?
Pituitary tumor/adenoma, ectopic ACTH secretion
If there is an ectopic ACTH secretion, where is it most likely coming from?
small cell lung cancer
Can the normal regulatory mechanism control the ACTH released from an ectopic source?
What hormones does the small cell lung cancer usually secrete?
ACTH (Cushing's) and ADH (SIADH)
What lab results will you see in hypercortisolism with an ACTH-Independent cause?
High cortisol level and suppressed ACTH
What lab results will you see in hypercortisolism with an ACTH-dependent cause?
High cortisol level and elevated ACTH
What would be DDx of patient presenting with excess cortisol with an suppressed ACTH level?
Exogenous glucocorticoid use (duh!)
Adrenal adenoma or adrenal corticocarcinoma
What imaging test would confirm either an adrenal adenoma or adrenal corticocarcinoma?
What imaging test would confirm a pituitary tumor?
What treatment has the greatest cure rate of pituitary tumor producing ACTH?
transsphenoidal surgery (90%)
What is a serious complication of radiation treatment of a tumor producing ACTH?
If an MRI confirms a large pituitary tumor, what is your plan now?
Refer to neurosurgery
What is the life expectancy of patients with untreated Cushing's syndrome of moderate to severe degree?
Less than 5 years with death usually occurring from CV disease
If the tumor secreting ACTH cannot be resected or chemo is not effective, what is another alternative?
Pharmacologic therapy (metyrapone, aminoglutethimide or ketaconazole)
What is the most common cause of Addison's disease?
Autoimmune adrenalitis (80%)
What are causes of Addison's disease (besides autoimmune adrenalitis)?
TB, bilateral adrenal hemorrhage, congenital adrenal hypoplasia, or surgical removal of adrenal glands
Does the autoimmune adrenalitis affect the adrenal medulla?
How does the patient with Addison's present?
weakness, fatigue, HYPERPIGMENTATION, anorexia, n/v, orthostatic hypotension and anxiety
Why does hyperpigmentation present with Addison's?
Elevated ACTH stimulates melanocytes
What is primary adrenal insufficiency commonly called?
Addison's Disease (HYPOcortisolism)
Is Addison's often associated with other autoimmune endocrine disorders such as diabetes mellitus, Hashimoto's thyroiditis, and vitiligo?
What lab results do you expect to see in a patient with Addison's?
Low AM cortisol (<3 mcg/dl)
ACTH level is elevated (>200 pg/ml)
serum Na+ LOW
serum K+ elevated
(if chronic) chronic deficiency of cortisol and aldosterone
In which sex is Addison's more common?
What causes the hyponatremia and hyperkalemia in patient with Addison's?
aldosterone deficiency
Will you see elevated or suppressed secretion of ACTH in Secondary Adrenal Insufficiency?
Suppressed ACTH
What is the most common cause of Secondary Adrenal Insufficiency?
Sudden/rapid withdrawal of long-term exogenous corticosteriod treatment
What are causes of Secondary Adrenal insufficiency?
Sudden/rapid withdrawal of long-term exogenous corticosteriod treatment
Pituitary tumors causing suppression of pituitary function
postpartum pituitary infarction
pituitary irradiation or surgery
head trauma
Will you see hyperpigmentation in Secondary Adrenal insufficiency?
Will you see electrolyte imbalance in Secondary Adrenal insufficiency?
What screening tests would you use on a patient you suspect of Primary Adrenal Insufficiency?
cosyntropin (ACTH) stimulation test
What is the normal response to the cosyntropin (ACTH) stimulation test?
increased cortisol level (>20 mcg/dl)
What result to the cosyntropin stimulation test would you expect to see in a pt with Addison's?
<20 mcg/dl increase in cortisol level
Can the cosyntropin stimulation test be given any time of day?
What result to the cosyntropin stimulation test would you expect to see in a pt with Secondary Adrenal Insufficiency?
increased cortisol level (>20 mcg/dl)
How do you treat Addison's Disease?
Replace mineralcorticoids and corticosteroids to physiologic levels with hydrocortisone, prednisone
Treat with Florinef.
Sick day rules - double glucocorticoid dose for a short time as possible for stress, acute illness, trauma, surgery
Emergency steroid kit
MedicAlert Bracelet - Adrenal Insuff - takes hydrocortisone
What is an important side effect of Florinef?
potent sodium-retaining effect
How do you treat secondary adrenal insufficiency?
Glucocorticoid (cortisone, dexamethasone, etc)
Treat the underlying pituitary disorder
Sick day rules - double glucocorticoid dose for a short time as possible for stress, acute illness, trauma, surgery
Emergency steroid kit
MedicAlert Bracelet - Adrenal Insuff
What are symptoms of the acute adrenal insufficiency (adrenal crisis)?
Extreme weakness, dehydration, hypotension, fever, nausea, vomiting, hypoglycemia, HA, confusion, coma
What tests must you order to make a diagnosis if you suspect your patient is having an adrenal crisis
Blood sample for immediate cortisol assay to distinguish adrenal insuff from other causes of shock.
Perform ACTH, electrolyte, BUN, creatinine and glucose assays
Administer a simplified cosyntropin stimulation test
Will the cosyntropin be able to stimulate a normal increase in serum cortisol in an adrenal crisis?
What will the cosyntropin stimulation test indicate in an adrenal crisis?
If the patient has primary adrenal disease (ACTH will be >200 pg/ml
How do you treat an adrenal crisis?
High doses of glucocorticoid
Broad-spectrum antibiotics (empiric therapy)
Treat the cause of the underlying stress if possible
Would you use Florinef with secondary adrenal insufficiency?
No. (Aldosterone should not be affected.)
What hormones increase in a normal HPA axis?
CRH, ACTH, and cortisol
What stimulates normal aldosterone release?
Increase in plasma potassium concentration
low renal perfusion pressure due to either hypovolemia or renal artery stenosis
Increased SNS activity
Eating real licorice
Taking oral contraceptives
What symptoms would clue you in to hyperaldosteronism?
Not taking diuretics
hypokalemia (unexplained)
Metabolic acidosis
What might cause excessive aldosterone production from the adrenal gland?
unilateral adrenocortical adenoma
bilateral adrenal hyperplasia
adrenal cancer
T/F. Excessive ACTH production causes adrenal hyperplasia.
What are secondary causes of hyperaldosteronism?
Most common cause - renal artery stenosis
Excess renin production by the kidneys
hypovolemia and CHF
What differentiates primary hyperaldosteronism from secondary hyperaldosteronism?
Plasma renin activity (primary-suppresses and secondary involves excessive)
How would you treat a unilateral adrenocortical adenoma?
unilateral adrenalectomy
How would you treat a bilateral adrenal hyperplasia?
Aldactone (aldosterone antagonist and diuretic)
How would you treat renal artery stenosis?
Revascularization procedures
What are common etiologies of hypoaldosteronism?
diabetic nephropathy
hypertensive nephrosclerosis
Are deficiencies of adrenal androgens in adults clinically important?
What symptoms occur as a result of excess adrenal androgens?
acne, hirsutism, and virilization
Catecholamine-secreting tumor of chromaffin cells arising from the adrenal MEDULLA or any location along the sympathetic nervous chain (paragangliomas)
Is pheochromocytoma rare?
What ages is peak prevalence of pheochromocytoma?
30-40 year olds with HTN
What are the rule of the 10s for pheochromocytoma?
10% are NOT associated with HTN
10% are extra-adrenal
10% are extra-abdominal
10% are malignant
10% occur in children
10% are bilateral adrenal tumors
10% are familial
What is the classic symptom triad for pheochromocytoma?
HA, sweating, and palpitation
***HTN (sustained or paroxysmal) is number one symptom but not in the triad
Clinical presentation of pheochromocytoma
HTN (sustained or paroxysmal)
HA, sweating, and palpitation
Facial pallor with mottled CYANOSIS, then flushing
Tachycardia with or without precordial pain
Abdominal pain
What may cause intermittent catecholamine release?
Exertion/postural change
Meals, alcohol use, smoking
Urination/straining at stool
Emotional stress, trauma, pain
GENERAL ANESTHESIA and barbiturates
Hormones/drugs: glucagon, ACTH, histamine
What tests would you order if you suspect your patient has pheochromocytoma?
Get labs on free T4, TSH, CBC, ESR, glucose
24 hr Urine for catecholamines
24 hr urine for metanephrines (metabolites of catecholamine) - VMA
When is the best time to obtain urine samples in a patient you suspect of having pheochromocytoma who is experiencing paroxysmal episodes?
During or immediately following an episode
Should you order direct blood and urine assays for epi and norepi if the patients is experiencing PAROXYSMAL hypertension?
No. Likely to be abnormal
Should you order plasma free metanephrine or plasma free catecholamines if the patients is experiencing PAROXYSMAL hypertension?
No. Likely to be abnormal
What are some complications from pheochromocytoma?
stroke and/or sudden blindness
cardiac arrhythmias
How would you treat pheochromocytoma?
TOC - Surgery (laparoscopic removal)
Pre-op alpha blocker or calcium channel blocker
Use beta blocker for persistent tachy or arrhythmias
For the HTN crisis: IV labetalol, Na nitroprusside or phentolamine
Why do you have to use a beta blocker AFTER an alpha blocker has been administered?
Use of a beta-blocker can initially INCREASE the blood pressure
How would you treat pheochromocytoma if you cannot operate on pheochromocytoma or it is metastatic?
Metyrosine (reduces catecholamines synthesis)