Adrenal insufficiency

Question 1

what does CRH stand for?

Answer 1

corticotropin-releasing hormone

Question 2

what does ACTH stand for?

Answer 2

adrenocorticotropic hormone

Question 3

what is CRH, and hence cortisol release in response to?

Answer 3

circadian rhythm (light-dark), stress + other factors

Question 4

where does the eye convey info to (circadian rhythm) and what are glucocorticoid’s role?

Answer 4

eye –> SCN (suprachiasmatic nuclei)

glucocorticoids are the secondary messenger from central –> peripheral clock

Question 5

cortisol effects

Answer 5

Increase blood sugar through gluconeogenesis
Suppress the immune system
Aids in the metabolism of fat, protein, and carbohydrates
Decreases bone formation.
Na retention, increased renal K loss
Help body respond to stress

Question 6

what are synthetic steroids used in?

Answer 6

many inflammatory disorders and replacement therapy in adrenal insufficiency

e.g. cortisol, prednisolone, methylprednisolone + dexamethasone

Question 7

what is addison’s disease?

Answer 7

EMERGENCY

primary hypoadrenalism
rare
destruction of the entire adrenal cortex

Question 8

cause of addison’s disease

Answer 8

90% - destruction by organ-specific autoantibodies

rarer: adrenal gland TB, surgical removal, haemorrhage, malignant infiltration

Question 9

clinical presentation addison’s disease

Answer 9

postural hypotension (head rush)
hyper pigmentation
vitiligo + loss of body hair in women

Question 10

what is an addisonian crisis?

Answer 10

vomiting, abd pain, profound weakness, hypoglycaemia

Question 11

what causes postural hypotension?

Answer 11

salt + water loss

Question 12

what causes hyper pigmentation?

Answer 12

stimulation of melanocytes by excess ACTH in primary hypoadrenalism

Question 13

what causes vitiligo + loss of body hair in women

Answer 13

dependence on adrenal androgens

Question 14

3 principles of investigating/diagnosing hypoadrenalism

Answer 14

1. demonstrate low cortisol secretion
2. find out if its dependent/independent on ACTH secretion
3. specific cause of adrenal failure

Question 15

Investigations for diagnosis of addison’s disease

Answer 15

single cortisol measurements (not that useful)
***short ACTH (tetracosactide) stimulation test is KEY

plasma ACTH level

adrenal antibodies

hyponatraemia, hyperkalaemia

Question 16

results of plasma ACTH level and what they mean

Answer 16

if high with low/low-normal cortisol - confirms primary hypoadrenalism

Question 17

what may a CXR + AXR show for Addison’s disease

Answer 17

TB

calcified adrenals

Question 18

Mx Addison’s disease

Answer 18

lifelong steroid replacement (tablets)

• hydrocortisone: morning + eve –> mimics normal diurnal rhythm
• fludrocortisone: synthetic mineralocorticoid

Question 19

Additional Mx Addison’s disease

Answer 19

Medic Alert bracelet/necklace
Increase steroid dose in stress: trauma, surgery, infection

(as in a normal person, ACTH would be up-regulated in these situations)

Question 20

Causes of secondary adrenal insufficiency

Answer 20

1. hypothalamic-pituitary disease

2. long-term steroid therapy leading to hypothalamic-pituitary-adrenal suppression

Question 21

Clinical features secondary adrenal insufficiency

Answer 21

Same as Addisons

BUT no pigmentation because ACTH levels are low

Question 22

How does the long ACTH test help in the diagnosis of secondary adrenal insufficiency

Answer 22

differentiates between primary and secondary adrenal failure

• normal adrenal glands –> reach certain levels of plasma cortisol conc by 4hrs
• primary: cortisol response is impaired throughout
• secondary: delayed but normal response is seen

Question 23

Tx secondary adrenal insufficiency

Answer 23

hydrocortisone (?can be IV or s/c)

fludrocortisone is unneccssary

Question 24

what happens if adrenal failure is secondary to long-term steroid therapy?

Answer 24

they will recover if steroids are withdrawn very slowly

Question 25

effects of over-replacement in treatment of Addisons

Answer 25

weight gain, peripheral oedema, insomnia

Question 26

effects of under-replacement in treatment of Addisons

Answer 26

lethargy, nausea, poor appetite, weight loss, increased pigmentation

Question 27

short acth stimulation test

Answer 27

During the test, a small amount of synthetic ACTH is injected, and the amount of cortisol, and sometimes aldosterone, the adrenals produce in response is measured.