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
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