Adrenal - Basic Science & Hyperfunction

Question 1

What 3 things are produced in the adrenal cortex?

Answer 1

Glucocorticoids, mineralocorticoids and androgens

Question 2

What is the main glucocorticoid hormone produced by the adrenal cortex?

Answer 2

Cortisol

Question 3

What is the main mineralocorticoid hormone produced by the adrenal cortex?

Answer 3

Aldosterone

Question 4

What type of cells are found in the adrenal medulla?

Answer 4

Chromaffin cells

Question 5

What is produced by the adrenal medulla? Give two examples.

Answer 5

Catecholamines e.g. adrenaline and noradrenaline

Question 6

The synthesis of all the corticosteroids in the adrenal cortex begins with what?

Answer 6

Cholesterol

Question 7

Which type of steroid hormone is produced in the zona glomerulosa of the adrenal cortex?

Answer 7

Mineralocorticoids

Question 8

What regulates mineralocorticoid activity?

Answer 8

Angiotensin II (RAAS) and K+ level

Question 9

Which type of steroid hormone is produced in the zona fasciculata of the adrenal cortex?

Answer 9

Glucocorticoids

Question 10

Which type of steroid hormone is produced in the zona reticularis of the adrenal cortex?

Answer 10

Androgens

Question 11

What regulates glucocorticoid activity?

Answer 11

ACTH

Question 12

What regulates androgen activity?

Answer 12

ACTH

Question 13

What hormone is released from the hypothalamus in the hypothalamic-pituitary-adrenal axis?

Answer 13

Corticotropin releasing hormone

Question 14

What hormone is released from the pituitary gland in the hypothalamic-pituitary-adrenal axis?

Answer 14

ACTH

Question 15

RAAS is a major regulator of aldosterone production. It is activated in response to what?

Answer 15

Decreased blood pressure

Question 16

What is the effect of aldosterone?

Answer 16

Increase sodium reabsorption, and increase hydrogen and potassium excretion

Question 17

Are corticosteroid receptors intra or extracellular?

Answer 17

Intracellular

Question 18

What is the name for the clinical state of chronic glucocorticoid excess?

Answer 18

Cushing’s syndrome

Question 19

When is cortisol usually at its highest and lowest levels in the normal circadian rhythm?

Answer 19

Usually lowest at midnight and highest upon waking

Question 20

What is the most common cause of Cushing’s syndrome?

Answer 20

Use of oral steroids

Question 21

What is the most common endogenous cause of Cushing’s syndrome?

Answer 21

Cushing’s disease (ACTH secreting pituitary adenoma)

Question 22

What are the two main ACTH dependent (high ACTH) causes of Cushing’s syndrome?

Answer 22

Cushing’s disease and ectopic ACTH production

Question 23

What are the two main ACTH independent (low ACTH) causes of Cushing’s syndrome?

Answer 23

Adrenal pathology (adenoma/hyperplasia) and iatrogenic steroid use

Question 24

What effect does Cushing’s syndrome have on blood pressure?

Answer 24

Hypertension

Question 25

What effect does Cushing's syndrome have on blood glucose levels?

Answer 25

Hyperglycaemia

Question 26

If individuals with Cushing's syndrome have an acid-base disorder, what is this most likely to be?

Answer 26

Hypokalaemic metabolic alkalosis

Question 27

What is the first line screening test for Cushing's syndrome?

Answer 27

Overnight dexamethasone suppression test

Question 28

In the overnight dexamethasone suppression test, 1mg of dexamethasone is given at midnight and a cortisol level is taken at 8am. If the individual has Cushing's syndrome, the cortisol level will be greater than what?

Answer 28

50nmol/L

Question 29

If an overnight dexamethasone suppression test is not suitable, what is another screening test that can be used for Cushing's syndrome?

Answer 29

24h urinary free cortisol

Question 30

A normal 24h urinary free cortisol would be less than what value?

Answer 30

280nmol/L

Question 31

Once a screening test has confirmed Cushing's syndrome, what investigation should be done next to determine between ACTH dependent and independent causes?

Answer 31

9am and midnight plasma ACTH and cortisol

Question 32

What is the first line diagnostic test for Cushing's syndrome?

Answer 32

48h low dose dexamethasone suppression test

Question 33

How much dexamethasone is given every 6 hours in the low and high dose dexamethasone suppression tests?

Answer 33

Low = 0.5mg / high = 2mg

Question 34

When performing 48h dexamethasone suppression tests, when should plasma cortisol levels be measured?

Answer 34

At time 0, and 6 hours after the last dose

Question 35

In individuals with Cushing's syndrome, in the 48h low dose dexamethasone suppression test, plasma cortisol levels will be greater than what 6 hours after the last dose?

Answer 35

50nmol/L

Question 36

What is the advantage of the 48h high dose dexamethasone suppression test over the low dose version?

Answer 36

High dose can differentiate between pituitary and non-pituitary causes of Cushing's syndrome

Question 37

If cortisol is suppressed after the 48h high dose dexamethasone suppression test, this suggests that the pathology is where?

Answer 37

Pituitary gland

Question 38

If cortisol is not suppressed after the 48h high dose dexamethasone suppression test, this suggests that the pathology is where?

Answer 38

Adrenal gland or ectopic

Question 39

If ACTH levels are low in someone with Cushing's syndrome, what is the first line imaging investigation?

Answer 39

Adrenal CT

Question 40

If ACTH levels are low in someone with Cushing's syndrome but there is no mass on adrenal CT, what investigations could be tried next?

Answer 40

Adrenal vein sampling or adrenal scintigraphy

Question 41

If tests indicate that Cushing's syndrome is likely of pituitary origin, what imaging investigation should be considered?

Answer 41

Pituitary MRI

Question 42

If tests indicate that Cushing's syndrome is likely of ectopic origin, what imaging investigation should be considered?

Answer 42

Contrast CT chest/abdo/pelvis

Question 43

If corticotropin releasing hormone causes cortisol to rise in someone with Cushing's syndrome, the underlying cause is most likely what?

Answer 43

Pituitary adenoma (Cushing's disease)

Question 44

If corticotropin releasing hormone doesn't cause cortisol to rise in someone with Cushing's syndrome, then the underlying cause is most likely what?

Answer 44

Ectopic ACTH production

Question 45

How should Cushing's syndrome caused by a pituitary adenoma be treated?

Answer 45

Trans-sphenoidal surgical removal of the adenoma

Question 46

How should Cushing's syndrome caused by an adrenal adenoma be treated?

Answer 46

Adrenalectomy

Question 47

Untreated Cushing's syndrome has increased mortality because of what?

Answer 47

Increased risk of vascular disease

Question 48

Pseudo-Cushing's syndrome is most commonly caused by one of what two things?

Answer 48

Alcohol excess or severe depression

Question 49

What are the 3 main features of primary hyperaldosteronism?

Answer 49

Hypertension, hypokalaemia, alkalosis

Question 50

What are the two main causes of primary hyperaldosteronism?

Answer 50

Adrenal adenoma (Conn's syndrome) or adrenal hyperplasia

Question 51

What is the first line investigation for primary hyperaldosteronism?

Answer 51

Plasma aldosterone to renin ratio

Question 52

What happens to aldosterone and renin levels in primary hyperaldosteronism?

Answer 52

Raised aldosterone, low renin

Question 53

Once a plasma aldosterone to renin ratio has confirmed primary hyperaldosteronism, what further investigations should be performed to identify the underlying cause?

Answer 53

CT abdomen and adrenal vein sampling

Question 54

How is primary hyperaldosteronism caused by Conn's syndrome treated?

Answer 54

Adrenalectomy

Question 55

How is primary hyperaldosteronism caused by adrenocortical hyperplasia treated?

Answer 55

Potassium sparing diuretic e.g. spironolactone

Question 56

What causes secondary hyperaldosteronism?

Answer 56

High renin levels as a result of low renal blood flow