Adrenal Physiology and Disease Flashcards
Aldosterone is synthesised in what part of the adrenal cortex?
Zona glomerulosa
Cortisol is synthesised in which part of the adrenal cortex?
Zona fasciculata
Outline the hypothalamic-pituitary-adrenal (HPA) axis
The hypothalamus secretes CRH causing the pituitary to secrete ACTH stimulating the adrenal cortex to secrete cortisol
How is aldosterone produced?
Renin produces angiotensin I which becomes angiotensin II which produces aldosterone
Cortisol causes increased/decreased blood pressure
Increased
What is the common name for primary adrenal insufficiency?
Addison’s disease
What occurs in Addison’s disease?
Complete autoimmune destruction of the adrenal cortex
Give some clinical features of Addison’s
Anorexia Fatigue Hypotension Abdo pain Pigmentation
What are the relative sodium and potassium levels in Addison’s?
Sodium is low and potassium is high
What occurs in a short synacthen test?
ACTH is injected and plasma cortisol is measured
What drugs are used in Addison’s?
Hydrocortisone - replaces cortisol
Fludrocortisone - replaces aldosterone
What is the commonest cause of secondary adrenal insufficiency?
Exogenous steroid use
What occurs in Cushing’s syndrome?
There is excess cortisol secretion
Give some features of Cushing’s
Easy bruising
Striae
Proximal myopathy
What is the commonest cause of primary Cushing’s?
Pituitary adenoma