Endocrine Disorders

Question 1

Give 3 examples of adrenal steroids

Answer 1

Mineralocorticoids (aldosterone)

Glucocorticoids (cortisol)

Adrenal androgens

Question 2

What are 2 types of adrenal hyper function?

Answer 2

Excess cortisol (Cushing’s)

Excess aldosterone (Conns syndrome)

Question 3

What are 2 types of adrenal insufficiency?

Answer 3

Hypocortisolism

Lack of aldosterone and cortisol (Addisons)

Question 4

What is aldosterone secretion activated by?

Answer 4

RAAS

Increased plasma [K+]

Question 5

How is RAAS activated?

Answer 5

Reduced renal perfusion

Increased sympathetic activity

Question 6

What can be used to diagnose primary hyperaldosteronism?

Answer 6

Aldosterone:Renin ratio is useful in diagnosis

Source of excess aldosterone is adrenal

Question 7

What effects does cortisol have on metabolism and other targets of cortisol action?

Answer 7

Brain

Bone

Cardiovascular system

Immune system

Kidney

Fetus

Skin/connective tissue

Question 8

What causes Cushing’s disease?

Answer 8

Iatrogenic
- excess ACTH secretion

1. Exogenous glucocorticoids activate cortisol receptor
2. At high doses will shut down HPA
3. Adrenal cortex atrophies with lack of ACTH stimulation
4. Several days may be required for adrenal to become response to ACTH again

Question 9

Describe the differential diagnosis of Cushing’s syndrome

Answer 9

Dexamthosone suppression test

Should be suppression with Cushing’s

High plasma ACTH

Question 10

Describe the differential diagnosis of Ectopic ACTH

Answer 10

No suppression with dexamethasone suppression test

Question 11

What is primary adrenal insufficiency?

Answer 11

Addisons disease

Insufficient cortisol and aldosterone

High ACTH and low cortisol

Progressive but can lead to adrenal crisis

Question 12

What is secondary adrenal insufficiency?

Answer 12

Pituitary or hypothalamic disease

Insufficient cortisol

Question 13

What are the clinical features of Addisons disease?

Answer 13

Hypotension

Plasma sodium: normal to low

Plasma pottasium: normal to high

High ACTH

Elevated plasma renin

Question 14

What dynamic test can help the diagnosis of Addisons disease?

Answer 14

ACTH stimulation test- Assess ability of adrenal to produce cortisol in response to ACTH

Question 15

Describe how to do a shot synthacthen test for ACTH stimulation

Answer 15

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

Question 16

Describe how to do a long synthacthen test for ACTH stimulation

Answer 16

NOT OFTEN NECESSARY since ACTH assay can distinguish

Adrenal cortex “shuts down” in absence of stimulation by ACTH - time needed to regain responsiveness

3 day stimulation by synacthen

In secondary adrenal insufficiency ONLY cortisol increases by >200 mmol/L over baseline