Adrenal Insufficiency Flashcards
what are the layers of the adrenal gland
outer: zona glomerulosa
middle: zona fasciculata
inner: zona reticularis
medulla
what does the zona glomerulosa secrete
mineralocorticoids
- aldosterone
what does the zona fasciculata secrete
glucocorticoids
- cortisol
what dose the zona reticularis secrete
androgens
what does the adrenal medulla secrete
adrenaline + noradrenaline
what increases secretion of aldosterone
increased potassium
angiotensin 2
effects of aldosterone secretion
increased sodium reabsorption + increases potassium excretion
- acts on the distal convoluted tubule + collecting duct
what is primary adrenal insufficiency
destruction of adrenal glands
- usually autoimmune: Addisons
what is secondary adrenal insufficiency
inadequate ACTH stimulating the adrenal gland due to problem with pituitary gland
- pituitary surgery
- infection
- ischaemia
- radiotherapy
what is tertiary adrenal insufficiency
inadequate CRH release from hypothalamus
- usually patients on long term steroids
symptoms of adrenal insufficiency
fatigue low libido weight loss nausea + vomiting increased skin pigmentation hypotension
what is Addisons disease
autoimmune destruction of adrenal glands
- primary adrenal insufficiency
blood results Addisons
LOW SODIUM
HIGH POTASSIUM
why is there increased skin pigmentation in Addisons
ACTH stimulates melanocytes to produce melanin
ACTH levels in
- primary adrenal insufficiency
- secondary adrenal insufficiency
primary - ACTH high (pituitary trying to stimulate adrenals to release cortisol)
secondary - ACTH low as problem with pituitary
diagnostic test for adrenal insufficiency
short synacthen test
- synthetic ACTH is given
how is a short synacthen test carried out
ideally performed in the morning
synacthen (synthetic ACTH) is given
blood cortisol measured at baseline, 30 mins + 60 mins after administration
normal response to synacthen test
baseline cortisol will double in response to ACTH
synacthen test indicating Addisons
baseline cortisol does not rise/less than doubles
treatment of Addisons
hydrocortisone - replaces cortisol
fludrocortisone - replaces aldosterone
what happens to doses of replacement steroids if a patient with Addisons is acutely unwell
doses are doubled until they have recovered
presentation of an addisonian crisis
severe hypotension
reduced consciousness
hypoglycaemia
hyponatraemia, hyperkalaemia
treatment of addisonian crisis
IV fluids
IV Hydrocortisone (100mg stat, then 100mg every 6 hours)
Dextrose if hypoglycaemic
cardiac monitoring + careful correction of electrolytes
what other conditions might be associated with Addisons
Hashimoto’s thyroiditis
Vitiligo
Type 1 DM
what is congenital adrenal hyperplasia
genetic condition resulting in partial-complete deficiency of enzyme needed for aldosterone + cortisol production
inheritance of congenital adrenal hyperplasia
autosomal recessive
what is deficiency in congenital adrenal hyperplasia
21a hydroxylase
biochemical pattern in congenital adrenal hyperplasia
low sodium
high potassium
high urea
(Addisonian picture)
symptoms of congenital adrenal hyperplasia in
- girls
- boys
girls - excess androgens
males - undervirilisation
treatment of congenital adrenal hyperplasia
long term steroid replacement
- hydrocortisone
- fludrocortisone
what infection can cause adrenal insufficiency in developing countries
TB
