Physiology 6 - Adrenal Disorders Flashcards Preview

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Flashcards in Physiology 6 - Adrenal Disorders Deck (12):


- 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


What are the side effects of exogenous glucocorticoids?
Think about the actions of cortisol

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


What is the danger of withdrrawing Glucocorticoid therapy?

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


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

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


What causes Congenital Adrenal Hyperplasia?

A defect in 21-hydroxylase
The enzyme involved in both Glucocorticoid and Mineralocorticoid formation (but not sex steroids)


Describe the pathophysiology of Congenital Adrenal Hyperplasia?

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


In short what are cushing's?

Hypersecretion of cortisol


whats the difference between cushing's disease and syndrome?

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)


How does cushing's present?

Wasting of the extremeties thanks to proteolysis

counter-intuitive rapid redistribution of fat to face/trunk


What is Addison's Disease?

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


What is a pheochromocytoma?

A neuroendocrine tumour in the adrenal medulla resulting in excess catecholamines


How does pheocrhomocytoma present?

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

Diabetogenic. (Adrenaline stimulates lipolysis and glucogenolysis)