Endocrine Disorders Flashcards
Give 3 examples of adrenal steroids
Mineralocorticoids (aldosterone)
Glucocorticoids (cortisol)
Adrenal androgens
What are 2 types of adrenal hyper function?
Excess cortisol (Cushing’s)
Excess aldosterone (Conns syndrome)
What are 2 types of adrenal insufficiency?
Hypocortisolism
Lack of aldosterone and cortisol (Addisons)
What is aldosterone secretion activated by?
RAAS
Increased plasma [K+]
How is RAAS activated?
Reduced renal perfusion
Increased sympathetic activity
What can be used to diagnose primary hyperaldosteronism?
Aldosterone:Renin ratio is useful in diagnosis
Source of excess aldosterone is adrenal
What effects does cortisol have on metabolism and other targets of cortisol action?
Brain
Bone
Cardiovascular system
Immune system
Kidney
Fetus
Skin/connective tissue
What causes Cushing’s disease?
Iatrogenic
- excess ACTH secretion
- Exogenous glucocorticoids activate cortisol receptor
- At high doses will shut down HPA
- Adrenal cortex atrophies with lack of ACTH stimulation
- Several days may be required for adrenal to become response to ACTH again
Describe the differential diagnosis of Cushing’s syndrome
Dexamthosone suppression test
Should be suppression with Cushing’s
High plasma ACTH
Describe the differential diagnosis of Ectopic ACTH
No suppression with dexamethasone suppression test
What is primary adrenal insufficiency?
Addisons disease
Insufficient cortisol and aldosterone
High ACTH and low cortisol
Progressive but can lead to adrenal crisis
What is secondary adrenal insufficiency?
Pituitary or hypothalamic disease
Insufficient cortisol
What are the clinical features of Addisons disease?
Hypotension
Plasma sodium: normal to low
Plasma pottasium: normal to high
High ACTH
Elevated plasma renin
What dynamic test can help the diagnosis of Addisons disease?
ACTH stimulation test- Assess ability of adrenal to produce cortisol in response to ACTH
Describe how to do a shot synthacthen test for ACTH stimulation
Measure baseline cortisol
30 minutes after 250 micrograms of synacthen (synthetic ACTH)
Adrenal insufficiency is excluded by an increase in cortisol of >200 or a 30 minute value <550