Disorders of the Adrenal Gland (McLeod)

Question 1

Name the 4 zones of the adrenal gland going superficial to deep

Answer 1

1. Zona glomerulosa (mineralcorticoids-aldosterone)
2. Zona fasciculata (glucocorticoids-cortisol)
3. Zona reticulata (androgens [DHEA])
4. Medulla (catecholamines

Question 2

What effect does aldosterone have on body fluid volume?

Answer 2

• Increased resorption of Na+ and water

- Increased excretion of K+ and H+

Question 3

Glucocorticoid: effects

Answer 3

1. Protects against hypoglycemia (Gluconeogenesis in the liver, proteolysis, lipolysis)
2. Decrease insulin sensitivity
3. Anti-inflammatory
4. Maintain vascular responsiveness to NE/Epi
5. Causes increase in GFR

Question 4

When does serum total cortisol need to be drawn? why?

Answer 4

between 8am and 9am

-secretion is diurnal and highest in the morning

Question 5

What value of total serum cortisol would make you think adrenal insufficency is very likely?

Answer 5

<3mg/dL = very likely adrenal sufficiency

Question 6

24 Hour Urine for free cortisol: important points

Answer 6

• discard the first void
• record last voiding time
• refrigerate urine

Question 7

Plasma ACTH: why is this test helpful

Answer 7

-Helps differentiate primary (adrenal) and secondary (pituitary) and tertiary (hypothalamic) cortisol imbalance

Question 8

What else is drawn with serum ACTH and when is it drawn?

Answer 8

• AM

- with serum cortisol

Question 9

ACTH stimulation test

Answer 9

• to see where the deficiency in cortisol is
• Give rapid/short acting cosyntropin IV (synthetic ACTH)
• Measure cortisol in the blood at 30-60 minutes

Question 10

If cortisol level doubles during a ACTH stimulation test?

Answer 10

Adrenal gland is working

Question 11

If cortisol level has a subnormal response during ACTH stimulation testing?

Answer 11

Adrenal Insufficeincy!

Question 12

Describe the Dexamethasone suppresion test

Answer 12

• get baseline cortisol level
• give 1mg dexamethasone PO at 11PM
• Measure plasma cortisol levels at 8AM

Question 13

Cushings Syndrome: diagnostics

Answer 13

1. Elevated 24hr urine
2. Midnight salivary cortisol elevated on 2 separate nights
3. Dexamethasone suppresion test: no change in cortisol level

Question 14

What imaging might you consider if you suspect an ectopic ACTH secreting tumor?

Answer 14

CXR to rule out lung mass

Pelvic ultrasound for ovarian mass

Question 15

Medical management of Cushing’s Syndrome: Adrenal enzyme inhibitors

Answer 15

1. Ketoconazole (can reduce cortisol at higher doses)

2. Metyrapone (inhibits cortisol synthesis)

Question 16

Medical management of cushings: adrenolytic agents

Answer 16

Mitotane- “medical adrenalectomy” kills adrenocortical cells!

Question 17

Most common cause of primary adrenal insufficiency

Answer 17

Autoimmune (Addison’s Disease) MC in the US

TB (worldwide most common)

Question 18

Most common cause of secondary adrenal insufficiency

Answer 18

exogenous steroid use

also MC overall

Question 19

Differentiate primary and secondary in regards to aldosterone and cortisol

Answer 19

In primary, both aldosterone and cortisol will be low

In secondary, aldosterone is intact but cortisol is low

Question 20

Clinical signs of adrenal insufficiency

Answer 20

• hypotension
• hypoglycemia
• salt cravings
• hyperpigmentation*** (caused by elevated ACTH)

Question 21

Adrenal insufficiency: Labs

Answer 21

1. CMP: hyperkalemia, hypercalcemia, hyponatremia
2. Eosinophilia
3. Andi-adrenal antibodies

Question 22

What are the 3 initial tests for adrenal insufficiency

Answer 22

1. plasma ACTH
2. plasma cortisol
3. ACTH stimulation test

Question 23

Adrenal crisis: Tx

Answer 23

1. IV steroids
2. Correct electrolyte abnormalities
3. Dextrose to address hypoglycemia
4. IV fluids/replace volume

Question 24

How will someone present with Conn’s Syndrome/Primary hyperaldosteronism?

Answer 24

• HTN
• Low K+
• polyuria and polydipsia

Question 25

What important blood test in addition to elevated aldosterone in the blood will help dx primary hyperaldosteronism?

Answer 25

Low renin in the blood

Question 26

What medication is the preferred medical treatment for primary hyperaldosteronism?

Answer 26

spironolactone

Question 27

Pheochromocytomas are associated with MEN1 or MEN2?

Answer 27

MEN2

Question 28

What 2 tests will help you diagnose a pheochromocytoma

Answer 28

1. 24hr urine for metanephrines and catecholamines (first line)**

then,
2. Clonidine suppresion test (normal: catecholamines go down)

Question 29

Prior to removing a pheochromocytoma, what medications should you give?

Answer 29

First: alpha blockers for BP control

then

Second: Beta blockers for the tachycardia