Adrenal Gland physiology and disease

Question 1

what are some of the common symptoms and signs of Addison’s disease?

Answer 1

• tiredness
• weight loss
• skin pigmentation/vitiligo
• hypotension
• vomiting/diarrhoea
• hypoglycaemia

Question 2

is Addison’s disease hypoactivity or hyperactivity of the adrenal gland?

Answer 2

hypoactivity

Question 3

which endocrine gland is affected in Addison’s disease?

Answer 3

adrenal gland

Question 4

what tests should be done to diagnose Addison’s disease?

Answer 4

• routine blood tests (incl U&E, FBC, glucose)
• random cortisol sample
• short Synachten test
• serology for anti 21-hydroxylase antibodies

Question 5

what are some clues to a possibility of Addison’s disease?

Answer 5

• unexplained hypoglycaemia
• previous weight loss or depression
• mismatch between disease severity and symptoms
• other endocrine problems

Question 6

how is Addison’s disease managed?

Answer 6

• with glucocorticoid and mineralocorticoid replacement

Question 7

what drugs are used to replace low cortisol levels in Addison’s disease?

Answer 7

• hydrocortisone
• prednisolone
• dexamethasone

Question 8

what drugs are used to replace low aldosterone levels in Addison’s disease?

Answer 8

• fludrocortisone

Question 9

what should you do in case of severe illness (eg Addisonian crisis)?

Answer 9

• IV hydrocortisone 100mg
• 50-100mg IV hydrocortisone every 8 hours
• once symptoms pass, reduce by half each day until back at the normal replacement levels

Question 10

what are some of the possible causes of Addison’s disease?

Answer 10

• autoimmune
• iatrogenic
• infiltrative
• inflammation
• infection
• infarction

Question 11

what special care should be taken for Addison’s disease patients when they are unwell for other reasons (eg flu)?

Answer 11

double dose of cortisol replacement while they are ill

Question 12

what should patients with Addison’s disease never do?

Answer 12

stop their glucocorticoid replacement suddenly

Question 13

what are the risks of suddenly stopping glucocorticoid replacement?

Answer 13

Addisonian crisis due to atrophy of adrenal gland while patient has been on replacement therapy

Question 14

which antibodies should be tested for Addison’s disease?

Answer 14

anti 21-hydroxylase antibodies

Question 15

if Addison’s disease is secondary, will the plasma ACTH levels after Synachten test be low or high?

Answer 15

low

Question 16

if Addison’s disease is primary, will plasma ACTH levels after Synachten test be low or high?

Answer 16

high

Question 17

what hormones trigger the release of adrenal hormones?

Answer 17

CRH from hypothalamus

ACTH from pituitary

Question 18

what class of steroids are secreted in the adrenal glands?

Answer 18

cholesterol-derived steroid hormones

Question 19

what are the layers of the adrenal gland called, and what class and type of hormones do they secrete?

Answer 19

zona glomerulosa - mineralocorticoids (aldosterone)
zona fasciculata - glucocorticoids (cortisol)
zona reticulata - sex hormones
medulla - catecholamines (adrenaline/noradrenaline)

Question 20

what are the two commonest causes of hyperaldesteronism?

Answer 20

bilateral hyperplasia

unilateral adenoma

Question 21

name the main feature found in hyperaldesteronism, and explain why

Answer 21

hypertension, because excess of aldosterone causes excess sodium retention, and therefore water retention and increased blood volume

Question 22

what investigations are carried out to diagnose hypercortisolism?

Answer 22

dexamethasone suppression test
24hr cortisol urine test
cortisol-ACTH test
imaging

Question 23

what are the main questions to be answered when diagnosing hypercortisolism?

Answer 23

• confirm diagnosis
• determine if ACTH dependent or independent
• determine if pituitary related or not
• localise lesion

Question 24

list possible causes of ACTH-dependent hypercortisolism

Answer 24

• pituitary adenoma

- ACTH secreting tumour elsewhere in body

Question 25

list possible causes of ACTH-independent hypercortisolism

Answer 25

- adrenal tumour | - steroid medication

Question 26

list some signs of Cushing's disease

Answer 26

``` moon face buffalo hump wasting in arms/legs central obesity striae hirsutism bruising ```

Question 27

what is another name for hypercortisolism?

Answer 27

cushing's syndrome

Question 28

what is hyperaldosteronism called, and what are its main features?

Answer 28

conn's syndrome | hypertension and hypokalaemia

Question 29

would you expect cortisol levels to be high or low at night?

Answer 29

low

Question 30

explain why a dexamethasone suppression test is done to diagnose cushing's disease

Answer 30

because administration of corticosteroids would normally suppress ACTH and adrenal production of cortisol. if dexamethasone is not causing suppression of body's ACTH/cortisol, there is something wrong in the feedback system

Question 31

what test is used to determine which side of a pituitary is affected by an adenoma in cushing's disease?

Answer 31

ACTH tested in blood sample from petrosal sinuses on each side of pituitary

Question 32

what ratio is used to screen for conn's syndrome?

Answer 32

aldosterone/renin ratio 24hr urine aldosterone test adrenal vein sampling

Question 33

what aldosterone/ratio would be suggestive of conn's syndrome?

Answer 33

>20

Question 34

what imaging technique is preferred to test for an adrenal mass?

Answer 34

abdominal CT scan

Question 35

what is the main cause of congenital adrenal hyperplasia?

Answer 35

21 hydroxylase deficiency

Question 36

which hormones depend on 21 hydroxylase?

Answer 36

mineralocorticoids (aldosterone) | glucocorticoids (cortisol)