Adrenal Glands + some Pituitary Flashcards
what is secreted by the zona glomerulosa?
aldosterone
what is secreted by the zona fasciculata?
cortisol / glucocorticoids
what is secreted by the zona reticularis?
androgens
what is the main cause of Addison’s?
70% is caused by autoantibody attack on the adrenocortical cells, +/- the loss of 21 hydroxylase
why does (postural) hypotension occur in Addison’s?
less mineralocorticoids –> less water and Na retention –> hypovolaemic
why does weight loss and skin pigmentation occur in glucocorticoids?
less glucocorticoids
why is there increased prolactin in Addison’s?
- less hormones
- no negative feedback
- more CRH which causes..
- more ACTH
- ACTH causes more prolactin
what “F…” medication is there to replace mineralocorticoids?
F for Fludrocortisone
what “H…” is to replace glucocorticoids?
H for hydrocortisone
what is the risk of missing your dose of glucocorticoid replacement?
lack of hydrocortisone can trigger ADRENAL CRISIS.
what is the risk of excess glucocorticoid replacement?
secondary cushings / osteoporosis / hypertension
how much does ur average adrenal gland weigh?
4g each
what is pan-hypopitruitarism ?
failed secretion of more than 1 pituitary hormone
how would you test low cortisol as part of pan-hypopituitarism?
give synacthen (manmade ACTH) – abrnomal if it doesn’t stimulate cortisol levels to go higher than 500
how would you test cortisol AND GH as part of pan-hypopit?
Controlled injection of insulin
- is cortisol abnormally low (under 500)
is GH low? (under 7mg)
what is DIDMOAD?
DI and DM diabeteetus
optic atrophy (blind)
deaf
what do you give to test for DI? and what is the R of A?
what would be the result if they don’t have diabetes?
IM desmopressin
should improve serum and urine osmolarity
typical treatment of DI (2)
oral desmopressin
nasal desmospray option
treatment of emergency DI?
desmopressin injection
evels of prolactin over 5000 show what????
a prolactinoma - pituitary adenoma secreting PRL
simon presents with ED, heachahe and problems with peripheral vision - what does ee av?
suspect a prolactinoma - late presentatio
prolactinoma women present with galactorheaa and what other 2 features?
irregular / absent periods
infertility :(
when is surgery implicated for prolactinoma?
if medication doesn’t work
what can Cabergoline be used to treat? (2)
prolactinoma and acromegaly - inhibits (dopamine for) PRL and GH!!
pros and cons of Cabergoline ?
effective – resolves periods, fertility + normal PRL
cons - depression and vomitting
what causes 99% of Acromegaly?
benign pituitary adenoma
what causes 1% of acromegaly? (2)
- ectopic GH
2. unregulated GHTH secretion
what is the relationship between GH and IGF-1?
GH binds to IGF-1 in the liver – IGF-1 can go onto bind to GH target tissue receptors causing the same effects.
remember some GH goes directly to target tissues
what two periods of life is GH most important?
postnatal and puberty
GH (and IGF-1) effect on …
- bone (2)
- somatic cells (1)
bone: growth plate elongation, increased bone mass
somatic cell: growth
what type of cancer is associated with acromegaly?
colon
also polyps
4 face and neck related features of acromegaly?
- migraine headaches
- visual problems
- thickening of structures - inc jaw and forehead
- snoring and sleep apnoea
somatostatin analogues are 1 of 3 medical treatments used for acromegaly
- 2 good
- 1 bad side effect
good - pituitary pituitary adenoma shrinkage. headache relief
bad - causes gallstones in 60%!!!!!!!!!!
surgery is #1st line for acromegaly (pit adenoma removal) - but what are the 3 medical treatment options???? (S and C and P)
s = somatostatin analogues
c = cabergoline (dopamine antagonist. best for acromegaly tumours that secrete PRL too)
p = Pegvisomant = (expensive GH receptor antagonist)
what is cushings disease vs syndrome?
disease - hypercortisol due to ACTH secreting anterior pituitary adenoma
syndrome - any cause of excess adrenal cortex hormone
3 sources of ectopic ACTH production
thymus
pancreas
lung - small cell lung cancer
cushing’s disease is caused by anterior pituitary adenomas.
what tumours can cause cushings syndrome?
adrenal adenomas - benign
adrenaocortical carcinoma
excess of which adrenal cortex hormone can cause protein loss? what does this cause clinically?? (4)
cortisol !!
thin skin, muscle wasting
proximal myopathy and oesteoporosis
name 2 cushings symptoms caused by excess mineralocorticoids?
hypertension and oedema
what is eye oedema called?
chemosis
effect of excess cortisol on weight?
increases weight –> obesity
can cause T2DM
is “buffalo hump” from acromegaly or cushings or addisons?
Cushings
interscapular fat pad
what is addisons?
primary adrenal cortex insufficiency
what is the impact of loss of 21 hydroxylase enzyme in addisons?
all the progesterone gets converted to testosterone – affecting the genitals
describe the aim of testing for Cushings diagnosis
to supress cortisol secretion using a high dose steroid (put negative feedback in play)
phase 1 of cushings testing
- take what?
- results disproving cushings
- results proving cushings
Dexamethason 1mg oral once
next morning:
- <50 isn’t
> 100 is
phase 2 cushings testing
- take what?
- results that prove cushings?
2mg dexamethasone x 2 days
>130 proves cushings
what is Cushings surgery called?
“hypophysectomy”
what “P.E” can be a S/E of testosterone replacement in pan-hypopituatrism?
prostate enlargement – urinary compression and speeding up prostate cancer development
testosterone replacement side effects….
P for ….
H for …
polycythemia (increased volume % of RBCs)
Hepatitis from oral tablets
what is the effect of SIADH on Na concentration?
lowers Na concentration = load of ADH causes loads of water retention so dilutes it
normal Na levels?
135 - 145
very low Na levels?
< 120
very high Na levels?
> 160
SIADH triggers (3)
pain, hypotension, nausea and vomitting
pathological cause of SIADH?
ADH secreting tumours
main 3 causes of Addison’s?
#1 = autoantibodies 2 and 3 = infection and malignancy
3 less common causes of Addison’s?
2 x iatrogenic
1 x pathological
- surgical removal of adrenal tissue
- some Cushing’s medications
- deposition diseases - haemochromatosis / amyloidosis
what is CAH in general?
how is it inherited?
congenital adrenal hyperplasia
affected steroid synthesis in cortex and gonads
autosomal recessive
what enzyme is essential for glucocorticoid and mineralocorticoid production?
21 -hydroxylase
95% of CAH
what is a “salt crisis” in CAH?
no mineralocorticoids = no Na retention
Crisis is hyponatraemia, hyperkalaemia and hypotension!!
result of excess testosterone in girls with CAH?
- virilisation of baby foetus
- ambigious genitalia
name 2 tumours that occur in the adrenal medulla
- neuroblastoma
2. phaechromocytoma
how good is the prognosis for adrenocortical carcinoma?
pretty bad - about 30% 5 year survival
describe phaeochromocytomas
Cause nor/adrenaline secretion
90% cause paroxysmal hypertension
(heart failure/ MI/ Stroke)
the 10% tumour!!!!!
