Adrenal Pathway Dysfunction Flashcards
What are the 3 corticosteroids?
Mineralocorticoids(aldosterone) Glucocorticoids (cortisol) Sex steroids (androgens and oestrogens)
What enzymes does angiotensin II turn on? What is synthesised as a result?
3, 11, 21, 18 hydroxylase= aldosterone synthesis
What are the main actions of aldosterone?
Controls BP, sodium, lowers potassium
What enzymes does ACTH turn on? What is synthesised as a result?
3, 11, 21, 17 hydroxylase= cortisol synthesis
How is cortisol released?
Diurnal rhythmn- peaks in the morning (8:30 am)
What is Addison’s disease?
Autoimmune destruction of adrenal cortex or TB of adrenal glands
How does Addison’s disease present?
Higher pigmentation Vitiligo (in mouth) Low BP (no cortisol or aldosterone) Extreme fatigue (low blood glucose due to loss of glucocorticoids) Hyponatraemia Hyperkalaemia
What are causes of adrenocortical failure?
Adrenal glands destroyed (Tb or autoimmune Addison’s)
Enzymes in steroid synthesis pathway not present (congenital adrenal hyperplasia)
Whats the most common cause of Addison’s? and in the UK?
TB- not in UK, here autoimmune is more common
What is the precursor to ACTH and MSH?
Pro opio melanocortin
How is Addison’s diagnosed?
Cortisol
What medication is given for Addison’s?
Fludrocortisone once daily to replace aldosterone
Hydrocortisone has too short a half life for once daily, can give 3 times daily
Prednisolone can be given as it has the right half life for a day
What is congenital adrenal hyperplasia?
Commonest cause is deficiency of 21 hydroxylase (missing gene), means you cannot synthesise cortisol or aldosterone
How long can you survive with congenital adrenal hyperplasia? How is it treated?
Only for a few hrs after you are born
Same treatment as Addison’s
What are knock on effects of congenital adrenal hyperplasia? How is this visible?
Excess synthesis of sex steroids (testosterone) before birth
In a girl they have ambiguous genitals, boys theres no visible sign
What hormones are completely missing in babies with congenital adrenal hyperplasia?
Cortisol and aldosterone
How does congenital adrenal hyperplasia present?
Neonate salt losing crisis
What happens if someone has a partial 21 hydroxylase deficiency? What age do they present and with what?
Lower levels of cortisol and aldosterone
Higher levels of testosterone
Present as children- precocious puberty in boys, hirtuism in girls
What happens in 11 hydroxylase deficiency? What do they present with?
Low cortisol and aldosterone
High sex steroids and 11 deoxycortisone
Virilisation, hypertension (!! even when cortisol is low!!), low potassium
What happens in 17 hydroxylase deficiency? What do they present with?
No testosterone
No cortisol
Excess 11 deoxycortisone
High BP, low K, no puberty, low glucose (glucocorticoid deficiency)
