ADRENAL STRUCTURE AND FUNCTION

Question 1

what is aldosterone under the control of?

Answer 1

renin

Question 2

what are glucocorticoids under the control of?

Answer 2

ACTH

Question 3

what are sex steroids under the control of?

Answer 3

ACTH

Question 4

what are noradrenaline and adrenaline under the control of?

Answer 4

sympathetic nervous system

Question 5

whats the most abundant hormone in the body?

Answer 5

dehydroepiandrosterone sulfate

Question 6

whats secreted in higher amounts… gluco or mineralocorticoids

Answer 6

glucocorticoids

Question 7

how do cortisol levels change throughout the day?

Answer 7

generally are higher in the morning when we wake up, and then fall throughout the day. This is called a diurnal rhythm (in people that do night shifts, this is reversed)

Question 8

how does the body stop corticosteroids binding to mineralocorticoid receptors (because they are so similar instructor)>

Answer 8

11 beta HSD2 can deactivate active steroids to produce inert steroids
(at high concentrations, corticosteroids can escape this mechanism and exert its effects)

Question 9

what is Addisons disease?

Answer 9

primary adrenal insufficiency

Question 10

what is primary adrenal insufficiency?

Answer 10

◦ A rare endocrine disorder that happens when the adrenal gland cortex is damaged and so isnt able to produce enough hormones such as aldosterone and cortisol

Question 11

what levels of cortisol, ACTH and CRH would you expect to see in primary adrenal insufficiency?

Answer 11

low cortisol, High ACTH and high CRH

Question 12

whats Waterhouse-friderichsen syndrome?

Answer 12

sudden increase in bp causes blood vessels in the adrenal cortex to rupture, filling up the adrenal glands with blood and causing tissue ischaemia and adrenal gland failure.- can cause primary adrenal insufficiency

Question 13

whats the most common cause of Addisons disease in HIC?

Answer 13

auto immune - where the cortex of the adrenal glands are attacked so cortisol and aldosterone cannot be produced.

Question 14

what are some causes of Addisons disease in LICs?

Answer 14

infections (TB, fungal, cytomegalovirus), infiltration by metastases, infarction, haemorrhage, adrenoleukodystrophy

Question 15

outline the significance of the adrenal cortex having a high functional reserve?

Answer 15

only a small amount of functional tissue can still do a pretty decent job of churning out enough hormones to meet the body’s needs. This means once there are symptoms, its usually a sign that the majority of the adrenal cortex has been destroyed.

Question 16

what symptoms and signs does Addisons disease cause?

Answer 16

hyponatremia
hyperkalaemia
hypobolemia
metabolic acidosis
salty food cravings
abdominal pain
fever
weight loss and anorexia
nausea, vomit
muscle and joint pain 
fatigue
dizziness worse on standing
disorientated
hyperpigmentation 
loss of pubic and armpit hair in women
decreased sex drive

Question 17

why can Addisons disease cause hyperpigmentation?

Answer 17

This decreased cortisol level causes the pituitary gland to become overactive so we end up producing pro-opiomelanocortin which is a precursor to melanocyte-stimulating hormone

Question 18

why doesnt the decrease in androgen production in Addisons disease cause issues for males?

Answer 18

because their primary site for producing androgens is the testes

Question 19

what is an adrenal crisis?

Answer 19

when the majority of the zona glomerulosa and zona fasciculata are destroyed. It can cause sudden pain on lower back, abdomen or legs with severe vomiting and diarrhoe, followed by dehydration, low bp and loss of consciousness. If left untreated this can be fatal.

Question 20

how can we diagnose Addisons disease?

Answer 20

random cortisol test
9am cortisol test
short synacthen test (diagnostic)

Question 21

what is the short synacthen test?

Answer 21

synacthen which stimulates the adrenal gland as its chemically similar to ACTH, if the adrenal glands are working normally then blood samples taken shortly after should show a rise in cortisol.

Question 22

what is secondary adrenal insufficiency?

Answer 22

lack of cortisol secretion due to lack fo ACTH release from pituitary gland

Question 23

whats the msot common cause of secondary adrenal insufficiency?

Answer 23

HPA axis suppression from long term steroid use

Question 24

how does secondary adrenal insufficiency present differently to Addisons disease?

Answer 24

no hyperpigmentation
no dehydation
no hyperalaemia
hypoglycaemia is more common

Question 25

what is tertiary adrenal insufficiency?

Answer 25

Decreased level of CRH released from the hypothalamus. decreased levels of ACTH = decreased cortisol

Question 26

what are some causes of tertiary adrenal insufficiency?

Answer 26

brain tumors, trauma to the base of the skull or sudden withdrawal from long-term use of exogenous steroids.

Question 27

what are some causes of causes of secondary adrenal insufficiency?

Answer 27

pituitary tumour

glucocorticoid use

Question 28

how is adrenal insufficiency treated?

Answer 28

3 x daily hydrocortisone

Question 29

what can you give a patient whos deficient in aldosterone?

Answer 29

fludrocortisone

Question 30

how should your dosing of steroids change when you have an illness or infection?

Answer 30

double the dose

Question 31

what is a steroid card?

Answer 31

Recently issued national guidance promotes a new patient-held Steroid Emergency Card to help healthcare staff identify patients with adrenal insufficiency and provide information on emergency treatment if the patient is acutely ill, experiences trauma, surgery or other major stressors

Question 32

what is cushings syndrome?

Answer 32

elevated levels of cortisol

Question 33

whats the most common cause of cushings syndrome?

Answer 33

exogenous corticosteroid use which causes suppression of HPA axis which can last as long as a year depending on the dose of the steroid.

other causes include pituitary adenomas, ectopic sources of ACTh

Question 34

what is cushings disease?

Answer 34

when ACTH producing pituitary adenoma causes hypercortisolaemia

Question 35

what are some signs and symptoms of cushings syndrome?

Answer 35

• thinning and bruising of the skin
• buffalo hump
• moon face
• cardiac hypertrophy
• hyperkalaemia
• muscle wasting
• osteoporosis
• dark facial hair on women
• abdominal striae which are purple and thick
• amenorrhoea
• central obesity
• hypertension
• which messes up normal ovarian and testicular function
• dampens the inflammatory and immune response
• impairs normal brain function

Question 36

why do patients with cushings syndrome get central obesity?

Answer 36

levated glucose -> elevates insulin -> actvates lipoprotein lipase so adipocytes can accumulate more fat molecules

Question 37

why can cushings syndrome cause hypertension?

Answer 37

cortisol can start cross-reacting with mineralocorticoid receptores because its structurally similar and so can ahve mineralocorticoid efefcts and retain fluid.

Question 38

why can cushings syndrome interfere with ovarian and testicular function?

Answer 38

• High levels of cortisol inhibit the secretion of gonadotropin releasing hormone from the hypothalamus

Question 39

what can put a patient in a pseudo-cushings state?

Answer 39

alcoholism
depression
obesity
anorexia
bulimia

Question 40

what are some tests for cushings syndrome?

Answer 40

24 hour urine free cortisol
1mg overnight dexamethasone suppression test
midnight serum cortisol
late night salivary cortisol

Question 41

outline how the 1mg overnight dexamethasone suppression test works?

Answer 41

give dexamethasone at 11pm and then chetck cortisol at 9am - should drop in normal cases