adrenal histology

Question 1

Where is cortisol made?

Answer 1

Zona fasiculata

Question 2

How do you test for Addisons? (go through specifics, dose etc) + causes of Addisons

Answer 2

Measure serum cortisol and ACTH

Then give 250MICROGRAMS of synthetic ACTH, IM

Measure the cortisol levels after 30 minutes and then after 60 minutes.

If cortisol still less than 10nm/L, it’s like Addisons.

Causes: Autoimmune, TB

Question 3

Normal TSH levels

Answer 3

0.5-5mU/L

Question 4

Patients with hypothyroidism have normal renal handling. If a patient has primary hypothyroidism but

hyponatremia
hyperkalemia
hypoglycemia

Answer 4

They have Addison’s aka adrenal failure alongside hypothyroidism - this is called Schmidt’s syndrome (antibodies against both)

Question 5

State the normal ranges for:
Sodium
Potassium
Urea
Glucose - fasting and non fasting

Answer 5

Na - 135-145 mmol/L
K - 3.5-5.3
Urea 2.1-8.5mmol/L

Fasting glucose - 3.9-5.6mmol/L
Non -fasting/after eating: up to 7.8 mmol/L

Question 6

High blood pressure and adrenal mass - 3 differentials

Answer 6

Phaeochromocytoma (adrenal medullary tumour secreting adrenaline - can suddenly kill you)
Conn’s syndrome (adrenal tumour secreting aldosterone)
Cushings

Question 7

Conn’s syndrome vs phaeochromocytomas

Answer 7

Conn’s - aldosterone secreting tumour; slow increase in blood pressure

Phaeo - adrenal medullary tumour that secretes adrenaline; sudden increase in blood pressure

Question 8

Symptoms of phaeo

Answer 8

Severe hypertension, arrhythmias, headaches and death

Question 9

Urgent treatment for phaeos

Answer 9

phenoxybenzamine ALPHA blocker

then give beta blocker
surgery

Question 10

Urgent treatment for phaeos

Answer 10

phenoxybenzamine ALPHA blocker

then give beta blockers
then arrange for surgery

Question 11

What is another name for Conn’s?

Answer 11

Primary hyperaldosteronism

Question 12

Hallmark of conns

Answer 12

Hypertension with hypokalemia and hypernatremia

Question 13

Diagnosis of Conn’s

Answer 13

Renin to aldosterone ratio

if renin is low, it’s from the hypertension from teh aldosterone

Question 14

Treatment of conn’s

Answer 14

Spironolactone

Then adrenalectomy

But if it’s bilateral you can’t take out the whole adrenal gland so you have to just give spiranolactone

Question 15

Cushing’s diagnosis

Answer 15

9 am cortisol - should be high in EVERYONE
12am SLEEPING midnight cortisol - should be LOW in NORMAL people

But if it is HIGHHHHHHHHH it’s cushing’s

Question 16

If the midnight cortisol is high, what do you do next?

Answer 16

Dexamethasone suppression test

even 1 dose of dexamethasone will switch off your ACTH, therefore your cortisol will become undetectable.

But in patients with Cushing’s DISEASE, they will not switch it off so cortisol will remain high

Question 17

Cause of Cushing’s syndrome

Answer 17

oral steroids or green herbal

Question 18

Causes of Cushing’s

Answer 18

Pituitary dependent Cushing's DISEASE (pit tumour)
Ectopic ACTH (5 percent)
Adrenal adenoma (10 percent)

Question 19

What is the diagnostic dose of low dose dex?

Answer 19

0.5mg dex every 6 hours for 48 hours

Question 20

Distinguish between cushing’s syndrome vs cushing’s disease

Answer 20

Cushing disease - cortisol suppression during high dose dex

Cushing syndrome - no suppression during high dose dex

No cortisol suppression with dexamethasone if cushing’s syndrome present

Cushing’s disease (aka pituitary ACTH overproduction) will respond to high dose dex only

If no high response at high dose dex, the ACTH is coming from elsewhere (ectopic) or there is an adrenal tumour producing excess cortisol

Question 21

If there is an indeterminate cause of cushing’s syndrome, what do you do next?

Answer 21

Pituitary sinus blood sampling (IPSS inferior petrosal sinus sampling with CRH stimulation); high ACTH stimulates pituitary

Note - it used to be high dose dex

Note 20 percent of the general population with pituitary MRIs will have a pituitary tumour which is normal