Physiology 6 - Adrenal Disorders

Question 1

Includes:

Answer 1

• Side effects of glucocorticoid therapy
• Withdrawel of glucocorticoid therapy
• Loss of -ve feedback in cortisol production
• Congenital adrenal hyperplasia
• Cushing’s disease/syndrome
• Addison’s Disease
• Pheochromocytoma

Question 2

What are the side effects of exogenous glucocorticoids?

Think about the actions of cortisol

Answer 2

• More infections (depressed immunity)
• Muscle wastage (increased proteolysis)
• Loss of percutaneous fat (thin, delicate skin)

Question 3

What is the danger of withdrrawing Glucocorticoid therapy?

Answer 3

Exogenenous cortisol has depressed CRH/ACTH through -ve feedback loops for a long time

This has caused the Adrenal cortex to atrophy

There’s a danger of adrenal insufficiency post withdrawel

Question 4

What everyday things can cause a loss of -ve feedback on cortisol production, and what would this cause?

Answer 4

Alcohol Caffeine and lack of sleep can all depress neurons responsible for -ve feedback of CRH/ACTH.

This enhances stress effects and boosts cortisol production

Causing a depressed immune system and so more infections

Question 5

What causes Congenital Adrenal Hyperplasia?

Answer 5

A defect in 21-hydroxylase

The enzyme involved in both Glucocorticoid and Mineralocorticoid formation (but not sex steroids)

Question 6

Describe the pathophysiology of Congenital Adrenal Hyperplasia?

Answer 6

Lack of aldosterone -> Dysfunctional salt balance

Lack of cortisol -> Dysfunctional glucose balance

Unused steroid precursors are used to make excess androgens

The lack of cortisol -ve feedback –> Excess ACTH –> Adrenal Hyperplasia

Question 7

In short what are cushing’s?

Answer 7

Hypersecretion of cortisol

Question 8

whats the difference between cushing’s disease and syndrome?

Answer 8

Cushing’s Disease occurs if the tumour is the pituitary gland (i.e. its secondary)

Cushing’s Syndrome occurs if the tumour is in the adrenal cortex (i.e. its a primary endocrine disorder)

Question 9

How does cushing’s present?

Answer 9

Wasting of the extremeties thanks to proteolysis

counter-intuitive rapid redistribution of fat to face/trunk

Question 10

What is Addison’s Disease?

Answer 10

Autoimmune descruction of the adrenal cortex leading to hyposecretion of all 3 classes of steroid hormones

Question 11

What is a pheochromocytoma?

Answer 11

A neuroendocrine tumour in the adrenal medulla resulting in excess catecholamines

Question 12

How does pheocrhomocytoma present?

Answer 12

Increases HR -> Increased BP
Increased vasoconstriction -> Increased BP

Diabetogenic. (Adrenaline stimulates lipolysis and glucogenolysis)