Endocrine - Online MedEd - Adrenals

Question 1

Adrenal gland sits on top

Answer 1

Of the kidney

Question 2

Adrenal medulla is in the middle. Produces…

Answer 2

Catecholamines

Question 3

Adrenal sits on kidney - has GFR… zones of adrenal

Answer 3

Glomerulosa - salt - aldosterone
Fasciculata - sugar - cortisol
Reticularis - sex - testosterone

Question 4

Cushing’s syndrome - pathophys (4 ways)

Answer 4

1) Lung tumour secretes ACTH (small cell)
2) Cushing’s disease - tumour on anterior pituitary that secretes ACTH
3) Ingesting steroids - i.e. treat autoimmune diseases (maybe taking too much)
4) Primary tumour of adrenal gland - produce cortisol
(ACTH driven will have elevated ACTH driving cortisol; those that are cortisol driven will have excess cortisol and low ACTH)

Question 5

Cushing’s syndrome cause by…

Answer 5

Cortisol excess

Some ACTH dependent, some ACTH independent

Question 6

Cortisol is responsible for

Answer 6

BP

Sugar control

Question 7

Cortisol excess causes

Answer 7

Hypertension
DM
Obesity
Look for: really bad acne, moon facies, truncal obesity (buffalo hump), stretch marks and purple striae on abdomen

Question 8

Work up of Cushing’s syndrome…

Answer 8

Need biochemical evidence of Cushing’s
Remember “low then high”!*
1) Do a low dose dexamethasone suppression test. First measure cortisol –> then give dexamethasone –> dexamethasone should suppress cortisol
*In this case, will fail to suppress –> gives you Cushing’ syndrome.
*Will also need to be sure it is excess cortisol - so get a 24 hour urine cortisol or a late night salivary cortisol
2) Next measure ACTH –> if ACTH is normal –> then the excess cortisol is coming from the adrenals –> do a CT/MRI and resect it.
But if ACTH is elevated –> now ACTH dependent, but not sure which one. NOW get high dose dexamethasone suppression
If got a pituitary tumour –> there will be some suppression –> so then it is Cushing’s disease –> resect it
IF fails to suppress –> now it is ectopic tumour –> go find it! very rare - do a pan scan (CT of chest and pelvis)

Question 9

Too little Cortisol is

Answer 9

Addison’s disease

Question 10

Addison’s disease…. what is it a problem of

Answer 10

Adrenal - Will also lose aldosterone!
Pituitary - RAS is intact
*Treatment is different

Question 11

Addison’s disease - what are the most common causes?

Answer 11

Adrenal destruction - autoimmune or TB related

Can also have dysfunctional anterior pituitary

Question 12

Patient presentation of addison’s

Answer 12

Acute - lose both cortisol (blood vessels) and aldosterone (hold onto Na) - will be hypotensive and N/V/coma - definitely ill!

Chronic - infiltrative, autoimmune, malignancy, orthostatic hypotension (not frank), hyper pigmentation (due to ACTH being made!), low Na and high K (no aldosterone)

Question 13

Diagnostic work up of Addison’s

Answer 13

1) S/S
2) Sufficient cortisol - do not do a random, want an early AM cortisol - if normal, then rule out; if Addison’s, low cortisol
3) Confirmatory - is it a deficient pituitary or adrenal. Do a cosyntropin stimulation test (give ACTH) - if cortisol rises, then problem is in the anterior pituitary –> now into pan hypo-pit –> do an MRI –> adrenal gland is intact, so just replace cortisol
Expect in Addison’s disease –> that the problem is in the adrenal gland –> so cortisol will not rise with administration of cosyntropin/ACTH –> do CT imaging/MRI of adrenal gland –> if adrenal gland is lost –> must replace both cortisol and aldosterone –> give cortisol and fludrocortisone

Question 14

Too much aldosterone is called

Answer 14

Conn’s syndrome

Question 15

RAS axis is independent of HPA axis… what is JG apparatus

Answer 15

Secrete renin

Question 16

Renin turns on

Answer 16

angiotensinogen

Question 17

Angiotensinogen converts

Answer 17

ANGI to ANGII

Question 18

ANGII turns on

Answer 18

Aldosterone

Question 19

Aldosterone activates

Answer 19

Channels in CD to reabsorb Na and excrete K
Which causes aquaporins to be inserted to reabsorb water
Esp with low flow through kidney system

Question 20

There could be a tumour that secretes too much aldosterone. Focus on which axis?

Answer 20

RAS axis

Not the HPA axis

Question 21

Pathology of Conn’s

Answer 21

1) Primary tumour is Conn
2) There could also be Renovascular hypertension/problem of renal artery - 1) Fibromuscular dysplasia in Female; 2) Atherosclerotic disease in old man
(Renovascular hypertension is considered appropriate response, but tumour is inappropriate)

Question 22

What is the presentation of Conn’s

Answer 22

HTN and hypoK*
Though not so much in real life…
Secondary hypertension (refractory to 3 or more meds)

Question 23

What is the first test to order for Conn’s

Answer 23

Aldo/renin ratio
If neither is elevated, there is a mimicker –> congenital adrenal hyperplasia and licorice ingestion
-If Aldo is elevated and so is renin –> renin is driving the aldo production so that aldo/renin<10 –> have renovascular hypertension –> fibromuscular dysplasia (stent), atherosclerotic disease (no stent, just deal with hypertension)
-If Aldo is elevated and renin is not! –> so autonomous secretion of aldo, so aldo/renin ratio > 30 –> now have Conn’s –> confirmatory test is salt supression

Question 24

For dx of Conn’s

Answer 24

Start with Aldo to renin ratio –> should be high (>30)
Next do a salt suppression test
Give a salt load –> what should happen is aldosterone is that aldosterone should decrease –> get MRI and cut it out
*Regardless, must get adrenal vein sampling before you go to resection
-Side without the mass is often hyper functioning so need to sample adrenal vein

Question 25

Pheochromocytoma - pathology

Answer 25

Catecholamine secreting tumour

From medulla

Question 26

Presentation of pheo

Answer 26

Ps
Paroxysmal
Pain/headache
Pressure/HTN
Palpitations/tachycardia 
Perspiration

Question 27

Diagnostic step of pheo

Answer 27

Plasma free catecholamines - for pheo crisis now

Or get 24 hour urine metanephrines - more sensitive, but not in crisis

Question 28

Once dx of pheo is confirmed… what to do?

Answer 28

CT/MRI abdomen

Adrenal vein sampling

Question 29

Pre-operative preparation of pheo…

Answer 29

Why? Because if poke pheo, can get massive release of catecholamines
Treatment is: Alpha blockade first, then beta blockade, then resect!

Question 30

Mass on adrenal gland is called

Answer 30

Incidentaloma

Question 31

Incidentaloma is…

Answer 31

Nothing, asymptomatic
What to do? Rule out Conn’s, Rule out Cushing’s, Rule out Pheo
How? 24 hour urine
Treatment?
Wait if <4cm
Resect if >4cm (because might be cancer or hyper functioning)