Primary Adrenocortical Insufficiency

Question 1

What are the 2 distinct areas of the adrenal glands and what do each of these areas produce?

Answer 1

Adrenal cortex: (the deeper you go the sweeter it gets)

• ZG= aldosterone
• ZF= cortisol
• ZR- androgens

Adrenal medulla (specialised part of sympathetic nervous system) 
-Ad and NAd

Question 2

What stimulates the release of the different adrenal hormones?

Answer 2

Aldosterone:
RAAS system activated after decreased BP detected in renal afferents (juxtaglomerular apparatus) i.e. Ag2 binds to AT-1 receptors to stimulate aldosterone release

Cortisol and androgens:
CRF released from hypothalamus
Acts on anterior pituitary to release ACTH
ACTH acts on adrenal gland to stimulate release of cortisol and androgens

Question 3

What are the possible causes of primary adrenocortical insufficiency?

Answer 3

Addison’s disease= AI destruction of adrenal glands which affects all layers and leads to adrenal atrophy
TB
Metastatic malignancy
Adrenal haemorrhage
Congenital adrenal hyperplasia
Drugs= Ketoconazole, Mitotane, metyrapone, etomidate

Question 4

What is the difference between primary and secondary adrenocortical insufficiency?

Answer 4

Primary= damage to adrenal glands leads to decreased production of adrenal hormones

Secondary= problems in higher centres (hypothalamus or pituitary) leads to decreased ACTH which leads to decreased stimulation of adrenal glands to secrete hormones

Question 5

How would someone with primary adrenocortical insufficiency present and why?

Answer 5

Weakness + fatigue= due to low blood glucose
Nausea and vomiting
Non-specific abdominal pain
Hypotension= low cortisol in times of stress (Adrenal crisis)
Pigmentation of mucous membranes and skin creases (can be seen in buccal membrane and creases of hands)

Question 6

How would primary adrenal insufficiency affect serum biochemistry?

Answer 6

Hyponatraemia + hyperkalaemia
-due to decrease aldosterone leading to decreased sodium retention and potassium excretion
High urea
Hypoglycaemia

Question 7

What are the 3 main tests which can be done to diagnose adrenal insufficiency in a patient with the signs and symptoms? What imaging can be done to accompany the test results?

Answer 7

1. Measure ACTH
   - will be HIGH in primary due to lack of negative feedback leading to pituitary over producing to try and stimulate adrenals
2. Synacthen test (ACTH stimulation test) = 1st line
   - 250mcg of IV ACTH given and blood collected 30 and 60 mins after
   - cortisol measure: >450nmol/L= normal
3. Measure adrenal antibodies
   - non-specific way to indicate possible Addison’s

Imaging:

• CXR/AXR= look for TB which might be cause
• CT of adrenals
• MRI if pituitary cause considered

Question 8

How is primary adrenocortical insufficiency treated?

Answer 8

Hydrocortisone= replaces glucocorticoids (cortisol)

• 10mg on waking
• 5mg at lunch
• 5mg late afternoon (not after 6pm)

Fludrocortison= replaces mineralocorticoid (aldosterone)

Emergency hydrocortisone pack given in case of adrenal crises
-IM hydrocortisone

Patient education on sick day rule
-know to increase steroid use based on individual plan

Question 9

If patient has un-treated hypothyroidism AND primary adrenocortical insufficiency, when should their thyroxine be given in relation to their glucocorticoid replacement?

Answer 9

Glucocorticoid first, then thyroxine

-thyroxine increased metabolism and can precipitate adrenal crisis w/o glucocorticoid

Question 10

How would someone with an Adrenal/Addisonian Crisis present? What causes this? How is it managed?

Answer 10

Reduced consciousness 
Hyponatraemia + hypernatraemia
Pyrexia 
Hypoglycaemic 
Very unwell 

Infection/sepsis 
Surgery 
Adrenal damage 
Withdrawal from steroids 
Lack of sick day regimen 

Management:
IV hypdrocortison 100mg stat 
Fluid resuscitation 
Correct hypoglycaemia 
Monitor patient and electrolytes