Adrenal Flashcards
Hormone type secreted by zone glomerulosa
mineralocorticoids
Hormone type secreted by zone fasciculata
glucocorticoids
hormone type secreted by zone reticularis
adrenal androgens
What is secreted by medulla of adrenal glands?
catecholamines
What regulates secretion from zone glomerulosa?
renin-angiotensin system and plasma K level
ACTH regulates secretion from which areas of adrenal cortex?
zona fasciculata and reticularis
What activates RAAS?
decrease in BP
Describe the pathway of activated RAAS?
BP falls
renin produced and converts angiotensinogen into angiotensin I
ACE converts angiotensin I into angiotensin II
Raises BP
Effects of cortisol on bone/connective tissue.
accelerates osteoporosis:
decrease serum calcium
decrease collagen formation
decrease wound healing
Metabolic effects of cortisol.
increase blood sugar
increase lipolysis, central redistribution
increase proteolysis
Effect of aldosterone on Na/K balance.
K/H excretion
increase Na reabsorption
Primary adrenal insufficiencies
Addison’s disease
Congenital adrenal hyperplasia (CAH)
Adrenal TB/malignancy
Secondary adrenal insufficiencies
due to lack of ACTH stimulation
iatrogenic (excess exogenous steroid)
pituitary/hypothalamic disorders
What is Addison’s disease?
autoimmune destruction of adrenal cortex, assoc. with other autoimmune diseases
Clinical features of Addison’s disease
anorexia, weight loss fatigue dizziness and low BP abdominal pain, vomiting, diarrhoea skin pigmentation (hand folds, buccal mucosa)
Diagnostic test for Addison’s
Short synacthen test
What biochemistry would make you suspicious of adrenal insufficiency?
low Na high K
hypoglycaemia
high ACTH
high renin, low aldosterone
Describe short synacthen teat.
Measure plasma cortisol before and 30mins after IV/IM ACTH injection
normal: baseline >250nmol/L
post-ACTH: >550nmol/L
Which hormone is insufficient in CAH?
17-OH-Progesterone
Which hormone/antibody is missing in autoimmune adrenal insufficiency?
21-OH antibody
Treatment for adrenal insufficiency.
hydrocortisone = cortisol replacement (15-30mg daily in divided doses)
fludrocortisone as aldosterone replacement
Patient with adrenal insufficiency needs to know sick day rule - what do they do when managing an illness at home with a fever?
hydrocortisone dose doubled or tripled (temp dependent) until recovery (2-3 days)
increased consumption of electrolyte-containing fluids
Treatment of acute adrenal crisis.
rapid infusion 1000ml saline within 1st hour or 5% glucose in isotonic saline - followed by continuous IV isotonic saline
hydrocortisone 100mg IV immediately followed by 200mg/d as continuous infusion for 24hr, reduce to 100mg/d the following day
