Adrenal/Pituitary Flashcards
What conditions results from hyperfunction of the adrenal glands?
Cushings syndrome
Hyeraldosteronism
What conditions result from hypofunction of the adrenal glands?
Primary adrenal insufficiency- addisons disease
Secondary adrenal insufficiency
What is the adrenal gland regulation and function?
- Hypothalamus releases corticotropin releasing hormone (CRH)
- Stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary
- ACTH stimulates the adrenal gland to release cortisol (also releases aldosterone and androgens)
- As cortisol levels rise it inhibits further release of CRH and ACTH through negative feedback
- Renin is released from the kidney (In response to ↓ blood pressure, salt depletion, CNS excitation)
- Conversion of angiotensinogen to angiotensin I then II stimulates aldosterone synthesis (Renal sodium and water retention and increased BP occur as a result of aldosterone secretion)
- Negative feedback to turn off renin release
What is involved with cushings syndrome?
↑adrenal function =↑cortisol production
Excess of cortisol in the plasma- hypercortisolism
What is the cause of Cushing’s Syndrome?
ACTH-dependent:
Pituitary tumor: excess ACTH secretion
Stimulates adrenal glands to secrete excess cortisol
Ectopic disease: ACTH secretion from another tumor
ACTH-independent: abnormal adrenocortical tissues (ACTH is functioning fine but you are still releasing too much cortisol)
Adrenal adenoma: benign
Adrenal carcinoma
Exogenous Steroids
What is the clinical presentation of Cushing’s Syndrome?
- Altered Fat Distribution- Central obesity
- Purple striae along the lower abdomen
- Facial rounding- “moon face”
- Supraclavicular fat pads
- Fat accumulation in the dorsocervical area- “buffalo hump”-Fat accumulation over chest & abdomen
- Hypertension
- Glucose intolerance
- Muscle weakeness
- Osteoporosis
- Psychiatric changes
- Gonadal dysfunction- Amenorrhea
How is Cushing’s syndrome diagnosed (confirmation)?
- Elevated urinary free cortisol- confirms hypercortisolism
- Plasma ACTH concentrations determine the etiology
Pituitary dependent
Ectopic ACTH
Adrenal Adenoma
Adrenal Carcinoma
What is the treatment of choice for Cushing’s syndrome?
Dependent on the etiology
Surgery is the treatment of choice
Transphenoidal removal of the pituitary tumor
Removal of the adrenal glands
Patient will require life-long treatment with glucocorticoids and mineralcorticoids
Steroidogenic inhibitors (Metyrapone (Metopirone®))- indications
Used for non-surgical candidates with cushings disease
Steroidogenic inhibitors (Metyrapone (Metopirone®)) - MOA
Steroidogenic inhibitors: inhibit synthesis and secretion of cortisol from the adrenal gland
Metyrapone (Metopirone®)- MOA
inhibits 11-hydroxylase activity in the adrenal cortex
Sudden drop in cortisol levels can result in an increase in plasma ACTH levels → increased androgenic and mineralcorticoid levels
Metyrapone (Metopirone®) (steroidogenic inhibitor)- indications
Used for Ectopic ACTH (something is causing the release of ACTH and it cant be reverse and these people are not candidates for surgery)
Metyrapone (Metopirone®) (steroidogenic inhibitor)- adverse effects
N/V
Hypertension
Alopecia
Hirsutism
Aminoglutethimide (Cytadren®) (steroidogenic inhibitor)- MOA
inhibits conversion of cholesterol to pregnenolone in adrenal glands
Blocks conversion of androstenedione to estrone and estradiol in the peripheral tissues
↓ production of cortisol, aldosterone, and estrogens
Aminoglutethimide (Cytadren®) (steroidogenic inhibitor)- Indications
Used for ectopic ACTH syndrome
Aminoglutethimide (Cytadren®) (steroidogenic inhibitor)- Adverse effects
N/V
Sedation
Hypothryoidism- blocks synthesis of thyroxine
Can cause problems with amenorrhea and fertility due to estrogen suppression
Ketoconazole (Nizoral) (Steroidogenic inhibitors)- MOA
imidazole antifungal agent
Also inhibits androstenedione synthesis
Ketoconazole (Nizoral) (Steroidogenic inhibitors)- Indications
Used for adrenal adenoma
Ketoconazole (Nizoral) (Steroidogenic inhibitors)- Adverse effects
Hepatotoxicity (need to monitor LFTs)
Gynecomastia (due to decreased testosterone levels)
Nausea
Ketoconazole (Nizoral) (Steroidogenic inhibitors)- drug interations
Inhibits CYP3A4, 1A2, 2C9, 2D6, 2A6
Ketoconazole (Nizoral) (Steroidogenic inhibitors)- absorption
Absorption requires an acidic pH
Administer 2 hours before antacids to reduce chance of decreased absorption
What are the adrenolytic agents?
Mitotane (Lysodren®)
Mitotane (Lysodren®) (adrenolytic agents)- MOA
cytotoxic drug that results in atrophy of the adrenal cells
Mitotane (Lysodren®) (adrenolytic agents)- indications
Used for adrenal carcinoma
Mitotane (Lysodren®) (adrenolytic agents)- adverse effects
Severely suppresses adrenal function (need to monitor urinary free cortisol)
N/V- administer w/ food
Lethargy and somnolence
Hypercholesterolemia
What causes primary hyperaldosteronism?
Abnormality is within the adrenal cortex
Aldosterone producing adenoma
Bilateral adrenal hyperplasia (BAH)
What do you screen with to detect primary hyperaldosteronism?
Screen with plasma aldosterone to plasma-renin activity ratio.
What causes secondary hyperaldosteronism?
Stimulation of the zona glomerulosa by an extraadrenal factor Usually the RAAS Other causes Excessive potassium intake Pregnancy CHF Cirrhosis Renal artery stenosis
What are the signs and sx of hyperaldosteronism?
Hypertension Hypervolemia Hypokalemia Hypernatremia- Leads to fluid retention Muscle weakness Fatigue Headache
What is the treatment for hyperaldosteronism?
Surgery if the cause is an adenoma
Spironolactone is the drug of choice : Aldosterone antagonist
Interferes with testosterone biosynthesis
What are the monitoring parameters with spirolactone?
Blood Pressure
Sodium and potassium
SCr
What are the adverse effects of spirolactone?
Hyperkalemia
Gynecomastia
Eplerenone (Inspra)
Hyperaldosteronism treatment
aldosterone antagonist
Less affinity for other steroid receptors
Use as an alternative for patients who can’t tolerate the anti-androgenic side effects of spironolactone
Monitor: Na, K, blood pressure, and renal function
Amiloride
Hyperaldosteronism treatment
potassium sparing diuretic
Not as effective as the aldosterone antagonists
Monitor: Na, K, blood pressure, and renal function
Typically need another agent for additional blood pressure control
What is Primary hypofunction of the adrenal gland (adrenal insufficiency) (addison’s disease) due to?
Destruction of the adrenal cortex
Deficiency in cortisol, aldosterone and androgens
What is secondary hypofunction of the adrenal gland (adrenal insufficiency) due to?
Suppression of the HPA axis from exogenous steroid use
ACTH deficiency
Deficiency in cortisol and androgens
Not mineralcorticoids
Which pathways does primary adrenal insufficiency block?
The glucocorticoids (cortisol) and mineralcorticoid (aldosterone)
What are the signs and sx of adrenal insufficiency?
- Weakness/fatigue
- Anorexia- Weight loss
- N/V, abdominal pain
- Can lead to adrenal crisis
- Hypotension- Postural dizziness
- Salt craving
- Hyperpigmentation
- Muscle/Joint symptoms
- Sexual dysfunction
What are the laboratory findings of chronic primary adrenal insufficiency?
Hyponatremia
Hyperkalemia
Hypercalcemia
Azotemia
How is adrenal insufficiency usually diagnosed?
COSYNTROPIN STIMULATION TEST FOR DIAGNOSIS
Cosyntropin is synthetic ACTH
In normal adrenal function you would expect plasma cortisol levels to rise after stimulation by ACTH
Administer 250 mcg cosyntropin IV or IM, draw serum cortisol levels at baseline and then at 30-60 minutes post dose
An increase in serum cortisol level ≥ 18 mcg/dL rules out adrenal insufficiency
What is another test that can be done for adrenal insufficiency diagnosis but is more specific and sensitive?
Low dose cosyntropin test
1 mcg cosyntropin IV with a baseline serum cortisol and a 30 minute post dose serum cortisol
Requires a more carefully timed sample
Administered IV
More sensitive than the 250 mcg dose test
Which side of the pathway needs replaced in primary adrenal insufficiency?
Both
What is the goal of treament with adrenal insufficiency?
Goal is to mimic endogenous cortisol production
What is diurnal variation?
More cortisol is produced in the early morning than in the evening (very little cortisol is produced from 6pm-3am)
What is the treatment for adrenal insufficiency?
Glucocorticoid replacement is needed in primary and secondary adrenal insufficiency
Endogenous secretion is ~5-10 mg/m2 of cortisol
Equivalent to 5 mg prednisone or 20 mg hydrocortisone
Short-acting glucocorticoid regimens:
Hydrocortisone
15-30 mg/day divided BID
Give ~ 2/3 of the total daily dose in the morning and 1/3 in the afternoon
What are the alternative glucocorticoid regimens?
Cortisone 25 mg in the am 12.5 in the pm
Prednisone 5 mg in the am 2.5 mg in the pm
Dexamethasone 0.5 mg in the am 0.25 mg in the pm
Prednisone and dexamethasone have longer half-lives
When should glucocorticoids be given?
In the morning.