Diagnosis + Treatment of Disease- Adrenal Gland

Question 1

How can disorders of the adrenal cortex be diagnosed?

Answer 1

• Specific blood tests
• Non-specific blood tests
• Specific dynamic tests

Question 2

What specific blood tests can be used to diagnose adrenal disease?

Answer 2

cortisol, aldosterone, ACTH

Question 3

What non-specific blood tests can be used to diagnose adrenal disease?

Answer 3

electrolytes, glucose, lipids, haematology

Question 4

What specific dynamic tests can be used to diagnose adrenal disease?

Answer 4

dexamethazone suppression test, ACTH stimulation test

Question 5

How can a functional adrenal tumour cause adrenal dependent HYPERadrenocorticism?

Answer 5

cortisol is increased + ACTH is decreased due to -ve feedback
Unaffected side shrinks due to decreased ACTH

Question 6

How can a functional pituitary tumour cause pituitary dependent HYPERadrenocorticism?

Answer 6

ACTH increased- tumour stimulates production of cortisol from both adrenals
Doesn’t respond to negative feedback

Question 7

What is the meaning of HYPERadrenocorticism?

Answer 7

excess of cortisol production

Question 8

Describe the ACTH stimulation test

Answer 8

• Take basal blood cortisol (take test before giving synthetic drug)
• Take blood cortisol 30-60mins after injection of synthetic ACTH
• Normal = clear stimulation of basal cortisol

Question 9

Describe the dexamethazone suppression test

Answer 9

• Take basal blood cortisol
• Take blood cortisol following injection of synthetic glucocorticoid (dexamethazone)
• Normal = clear suppression of basal cortisol

Question 10

What can be used to treat over-production of adrenal hormones?

Answer 10

• adrenal steroid synthesis inhibitors (Trilostane)

- dopamine receptor agonists (horses ONLY)

Question 11

How do adrenal steroid inhibitors work?

Answer 11

Competitive inhibitor of 3-B hydroxysteroid dehydrogenase = inhibits corticosteroid synthesis
- V lipid soluble

Question 12

What adverse effects could occur from treatment w/ adrenal steroid inhibitors?

Answer 12

• HYPOadrenocorticism
• electrolyte abnormalities
• inhibits progesterone synthesis

Question 13

What is cushing’s disease in horses caused by?

Answer 13

loss of dopaminergic inhibition to the intermediate lobe of the pituitary

Question 14

What is used to treat cushing’s in horses?

Answer 14

dopamine receptor agonist (pergolide)

Question 15

What condition is Addisons caused by?

Answer 15

HYPOadrenocorticism

Question 16

How is Addisons treated?

Answer 16

Replacement therapy w/ glucocorticoids +/or mineralocorticoids

Question 17

Describe the key pharmokinetics of glucocorticoids

Answer 17

Absorption = by GI tract, mm, skin
Distribution = transported bound to plasma proteins

Question 18

What adverse effects may occur after treatment w/ corticosteroids?

Answer 18

• toxic effects after long-term high doses

- Iatrogenic hyperadrenocorticism following withdrawal of long-term use of high doses- suppress ACTH secretion