Exam 4: Adrenal Gland Flashcards
What two classes of hormones does the adrenal gland produce?
Steroids and catecholamines
Where in the adrenal gland are catecholamines and peptides made?
Medulla
Where in the adrenal gland are mineralocorticoids (aldosterone (salt)) made?
The cortex, specifically zona glomerulosa
What does aldosterone do?
Regulates salt balance and blood volume
What controls the release of aldosterone?
AT II and serum potassium concentrations
Where in the adrenal gland are glucocorticoids produced?
Zona fasciculata
What does cortisol do?
Increases blood sugar and has many metabolic effects
What controls the release of cortisol?
ACTH, CRH
Where in the Adrenal Gland are androgens made?
The cortex, specifically the zone reticularis
What controls the release of androgens?
ACTH, CRH
What controls the release of catecholamines?
Preganglionic sympathetic neurons
Cortisol has negative feedback on what two things? This results in decreased production of what?
Cortisol has negative feedback on the hypothalamus, so it does not secrete CRH, and it has negative feedback on the anterior pituitary so it does not secrete ACTH
What are the functions of cortisol?
Stimulates gluconeogenesis, decreases glucose uptake by tissues, anti-inflammatory effects, reduces bone formation, increases proteolysis, decreases plasma Ca, and inhibits collagen formation
When are cortisol levels the highest?
The morning
What results from prolonged exposure to excess glucocorticoids and androgens?
Cushing’s syndrome
What are the clinical features of Cushing’s syndrome?
Amenorrhea, strifes, hyperpigmentation, central obesity, HTN, proximal muscle wasting, signs of androgen excess, and emotional lability
What are the two different types of cushings disease?
ACTH dependent (80%) and ACTH independent (20%)
What is the most common cause of Cushing’s syndrome?
Pituitary hypersecretion of ACTH, responsible for most cases of Cushing syndrome. This is known as cushings disease
What is the most common case of ACTH independent Cushing syndrome?
Latrogenic or fictitious Cushing’s syndrome
Is ACTH elevated or lowered in ACTH dependent Cushing’s syndrome?
What about ACTH independent?
Dependent: High
Independent: low
What is the gold standard for diagnosis of Cushing’s syndrome? What other tests can be done?
24 hour urinary free cortisol excretion is gold standard.
Late night salivary cortisol and low dose dexamethasone suppression test may also be used
What must you rule out when diagnosing Cushing’s syndrome?
You must exclude exogenous glucocorticoids
How is the lose dose dexamethasone suppression test performed?
1mg oral dose of dexamethasone at 11pm and serum cortisol levels are measured at 8am the following morning
What is an abnormal result in the low dose dexamethasone suppression test?
Elevated cortisol of >5mcg/dL is an abnormal result.
This is highly suspicious for non-suppressive cortisol production from ACTH independent etiology
What is the management of cushings disease caused by exogenous corticosteroids?
Taper to the lowest therapeutic dose to control symptoms
What is the management of Cushing’s syndrome caused by pituitary adenoma?
Transsphenoidal resection
What is the management of Cushing’s syndrome caused by adrenal tumor?
Adrenalectomy
What is the management of Cushing’s syndrome caused by adrenal hyperplasia, inoperable tumor, or other malignancy?
Medial therapy is warranted
What is the first line medical management of Cushing’s syndrome?
Ketoconazole (at higher doses, it inhibits steroidogensis)
What drugs should you give for Cushing’s syndrome if ketoconazole was not effective?
Metyrapone
What medication can be given for Cushing’s syndrome to achieve a “medical Adrenalectomy”?
Mitotane
What are the functions of aldosterone?
Increase blood pressure, increase ECF volume, increase tubular reabsorption of sodium, promote excretion on potassium, and water retention
What are the most common etiologies of primary hyperaldosteronism (Conns syndrome)?
- Bilateral idiopathic adrenal hyperplasia is most common
- Unilateral aldosterone producing adenoma is second most common
What are the clinical features of primary hyperaldosteronism?
HTN, hypokalemia, muscle weakness, paresthesias, HA, polyuria, and polydipsia
How is primary hyperaldosteronism diagnosed?
1) increased plasma aldosterone concentration (PAC)
2) Decreased plasma renin activity (PRA) or plasma renin concentration (PRC)
3) Spontaneous hypokalemia
What imaging can be obtained for primary hyperaldosteronism and why?
CT abdomen to evaluate for adrenal adenoma or adrenal hyperplasia
If a patient being worked up for primary hyperaldosteronism does not have spontaneous hypokalemia, what must be done?
Confirmatory testing is required to establish diagnosis
What is the management for a patient with primary hyperaldosteronism caused by a unilateral adrenal adenoma?
Surgical removal
What is the management of a patient with primary hyperaldosteronism caused by bilateral idiopathic adrenal hyperplasia?
- Mineralocorticoid receptor antagonist (Spironolactone is first line!!)
- Antihypertensives
- Monitor serum K, creatinine, and BP during first 4-6 weeks of therapy
What disease results in decreased synthesis of all adrenocortical hormones, including cortisol, aldosterone, and androgens, however ACTH is high?
Primary adrenocortical insufficiency AKA Addison’s disease
What causes secondary adrenocortical insufficiency?
Failure of the corticotrophs to adequately secrete ACTH
What causes tertiary adrenocortical insuffiency?
Insufficient CRH from the hypothalamus
What is the difference between primary adrenocortical insufficiency (AI) vs secondary and tertiary?
Secondary and tertiary AI clinical features are related to cortisol and androgen deficiency. Aldosterone is normal and hyperpigmentation does not occur
What is the most common etiology of primary AI?
Autoimmune destruction of the adrenal cortex
What is the most common cause of secondary AI?
Suppression of the HPA axis through abrupt cessation of exogenous steroids
What is the one labs that is high in primary AI?
ACTH
What lab is normal with secondary AI?
Aldosterone
What lab is normal and what is lab is low in tertiary AI?
Aldosterone is normal and CRH is low
What are the clinical features of primary AI?
Hyperpigmentation, salt craving, postural hypotension, depression/anxiety, and decreased pubic and axillary hair in females
How is AI diagnosed?
- Serum AM cortisol
- cosyntropin (ACTH) stimulation test
- ACTH, renin, and aldosterone
What is an abnormal result of the cosyntropin stimulation test?
Cortisol fails to increase by 7mg/dL above baseline, OR to >18mcg/dL
What are the management options of AI?
- Short acting glucocorticoids ( Hydrocortisone BID to TID)
- Long acting glucocorticoids (dexamethasone, prednisone)
- MIneralocorticoid (Fludrocortisone)
- Consider oral DHEA replacement in women
What is it called when a patient has a catecholamine secreting tumor that arises from chromaffin cells of the adrenal medulla?
Pheochromocytoma
What is the clinical presentation of pheochromocytoma?
Classic triad: Episodic headache, tachycardia, and sweating
-paroxysmal HTN
What are the most common etiologies of pheochromocytoma?
- 60% are sporadic
- 40% are familial
Are pheochromocytomas usually malignant or benign?
90% are benign
What do most catecholamine secreting tumors arise from?
The adrenal medulla
Patient presents with classic paroxysmal “attacks”, refractory HTN, and an abdominal mass. What should you suspect?
Pheochromocytoma
How is pheochromocytoma diagnosed?
- Plasma metanephrines
- 24 hour urine catecholamines, metanephrines, and VMA
- Clonidine suppression test
- thyroid function tests
- plasma epi and NE
What imaging should be ordered to diagnose pheochromocytoma?
CT abdomen without contrast
What is the management of pheochromocytoma?
- Chemical sympathectomy stabilizes patient until surgery
- Surgery is definitive
- B blocker and alpha blocker
What is it called when a patient has an adrenal mass lesion greater than 1cm in diameter, serendipitously discovered by radiologic exam?
Adrenal incidentaloma
What is the management for an adrenal incidentaloma that has a negative work up, is likely benign, and is <2cm?
Repeat imaging at 6 months and repeat dexamethasone supression test every year for 4 years
What is the management for an adrenal incidentaloma that has a negative work up, is likely benign, and is >2cm?
Consider surgical resection
