Adrenal gland Flashcards
3 zones of adrenal cortex on histology
zona glomerulosa (most exterior)
zona fasciculata
zona reticularis
2 parts of adrenal gland
outer cortex
inner medulla
what type of cells are in the medulla
chromaffin cells
think Chromaffin Cells in the Centre
what do chromaffin cells secrete
examples (3)
catecholamines
eg epinephrine (adrenaline), norepinephrine (noradrenaline), dopamine
(think Chromaffin Cells in the Centre produce Catecholamines)
generally what does the adrenal cortex make
corticosteroid hormones
what does the zona fasciculata (middle layer of cortex) secrete
cortisol
which zone of the adrenal cortex is inner most (next to medulla)
zona reticularis
what does the zona glomerulosa (outer layer of the cortex) secrete
aldosterone
what does the zona reticularis (inner layer of cortex) secrete
adrenal androgens
what regulates the production of corticosteroids in the zona glomerulosa
which corticosteroid is produced here
RAAS pathway (angiotensin II)
aldosterone
in which physiological state does the RAAS pathway stimulate the production of aldosterone from the zona glomerulosa of the adrenal cortex
hypotension
what regulates the production of corticosteroids in the zona fasciculata
what corticosteroid is produced here
ACTH
cortisol
where does ACTH come from
what does it stimulate (specifically)
what is produced bc of ACTH
pituitary gland
zona fasciculata of the adrenal cortex
cortisol
what does cortisol from the zona fasciculata of the adrenal medulla production cause (3)
fat breakdown
muscle breakdown
decreased glucose uptake into cells (hyperglycaemia)
which zones are stimulated by ACTH
zona fasciculata
zona reticularis
what regulates the production of corticosteroids from the zona reticularis
what corticosteroid is produced here (example)
ACTH
precursor androgens eg DHEA
what imaging is used to look at the adrenal glands (2)
what do the glands look like on imaging
MRI
CT
upside down Y
generally, what is cushings
hyperfunction of adrenal glands = excess cortisol secretion
aetiology of cushings (4)
ACTH secreting pituitary tumour
adrenal tumour
ectopic ACTH production (eg lungs, pancreas)
iatrogenic - high dose steroids (eg asthma)
aetiology of cushings disease (different from cushings syndrome)
ACTH secreting pituitary tumour
who typically present with cushings
young women
what does excess cortisol in cushings cause (biochem)
fat breakdown
muscle breakdown
decreased glucose uptake into cells (hyperglycaemia)
increased ACTH in cushings causes an increase in which corticosteroids (2)
cortisol
precursor androgens
which 2 adrenal cortex zones does increased ACTH production in cushings affect
zona reticularis
zona fasciculata
presentation of muscle breakdown in cushings
proximal myopathy
presentation of decreased osteoblast activity from increased cortisol in cushings
osteoporosis
why does cushings present with skin thinning and easy bruising
protein is removed form skin with increased cortisol production
BMI of someone with cushings and descriptive terms (4)
overweight
central fat distribution - ‘lemon on sticks’
‘moon face’
buffalo hump (on back)
why are people with cushings overweight
increased steroids causes lipolysis = excess plasma fat
what does increased precursor androgens cause in cushings (3)
hirsutism (male facial hair pattern in females)
acnes
amenorrhea (period stops)
why do people with cushings get abdominal striae (stretch marks) (2)
obesity
easy bruising
first line investigations for cushings (2)
ACTH
overnight low dose screening test
why do you want to give high dose steroids as an investigation in cushings if they are already over producing steroids…
to see if exogenous steroids stop the production of endogenous steroids (in cushings this doesnt happen but normally it will)
if the overnight low dose screening test for cushings is <50 what does this mean
what do you do next
cortisol has decreased in result of exogenous steroids = NORMAL physiological response
nothing, they dont have cushings
if the overnight low dose screening test for cushings is >50 what does this mean
what do you do next
ACTH is still being produced even after the addition of exogenous steroids
= probably has cushings
low dose and high dose diagnostic test
what is the overnight screening test for cushings (drugs)
1mg dexamethasone at midnight, test cortisol levels the next morning
what is the low dose diagnostic test for cushings (drugs)
2mg dexamethasone OD for 2 days, test cortisol levels 6 hours after last dose
what is the high dose diagnostic test for cushings (drugs)
2mg dexamethasone QDS for 2 days, test cortisol levels 6 hours after last dose
why do you do high dose diagnostic test for cushings
to differentiate between pituitary and ectopic ACTH production
low cortisol in high dose diagnostic test
high ACTH <300
ACTH secreting pituitary tumour causing cushings
high cortisol
low ACTH <1
adrenal tumour causing cushings
high cortisol in high dose diagnostic test
v high ACTH >300
ectopic ACTH production causing cushings
cushings treatment
metyrapone - to reduce ACTH production before surgery fix cause (surgery at site or just remove the adrenal glands (less risky than brain surgery))
obese but osteoporosis
cushings
which aetiology of cushings causes hypokalaemia
ectopic
investigation for ectopic cushings
CXR for lung ACTH producing tumour
prognosis of cushings
bad
high mortality
what physiological change in the adrenal glands occurs with high ACTH
adrenal hyperplasia
what is acquired adrenal hyperplasia called
cushings
apart from cushings, what other type of adrenal hyperplasia can you get (2)
congenital adrenal hyperplasia (CAH)
tumours
inheritance pattern of CAH
autosomal recessive
which enzyme is missing in CAH
what does this result in
enzyme for cortisol secretion (21 hydroxylase)
increased ACTH to compensate for low cortisol (negative feedback) = increased precursor androgens (testosterone)
is congenital adrenal hyperplasia usually unilateral or bilateral
bilateral
are adenomas or carcinomas more common in the adrenal glands
adenoma
what syndrome can an adrenal adenoma cause
conns syndrome
which zone of the adrenal cortex does conns syndrome have a tumour in
zona glomerulosa
in conns syndrome, which corticosteroid is produced in excess
aldosterone (tumour is in the zona glomerulosa)
what does excess aldosterone in conns syndrome cause (4)
note: think about the usual stimulus of aldosterone production
hypertension
hypokalaemia
cardiac failure
sodium retention
excess aldosterone
conns syndrome
conns syndrome investigations (3)
ARR (aldosterone to renin ratio)
adrenal imaging
saline suppression test
what would you expect the ARR to be in conns syndrome
> 2400
ARR = aldosterone to renin ratio
conns syndrome treatment
surgery MR antagonist (spironolactone) if bilateral hyperplasia (not an adenoma)
is conns syndrome always caused by a tumour
no can be caused by just hyperplasia
when is CAH usually diagnosed
infancy
how does CAH present in teenagers (4)
precoscious puberty
acne
hirsute (male hair pattern)
oligomenorrhoea (irregular periods)
how does CAH present in infancy (1)
genital ambiguity
investigations for CAH
genetic mutation analysis
CAH treatment for kids
low dose steroids (to replace steroids and fix the feedback system)
CAH treatment for adults
control androgen excess (dont give steroids!)
autoimmune adrenal condition
addisons disease
is addisons disease hypo or hyper function of the adrenal gland
how does it come about
hypofunction from autoimmune destruction
most common cause of primary adrenal insufficiency
addisons
aetiology of acute addisons crisis (3)
infection (TB, HIV)
waterhouse-friderichsen (meningococcal septicaemia)
newborns
which hormones are reduced in addisons
steroids
precursor androgens
aldosterone
which hormone is increased in addisons (think negative feedback)
ACTH
what is lost in an adisonian crisis due to reduced aldosterone
what does this cause
Na = dehydration
adisonian crisis presentation (9)
vomiting abdo pain hypotension confusion tachycardia hypoglycaemic hyponatraemia hyperkalaemia dehydration
addisons disease presentation (chronic) (4)
weight loss
buccal pigmentation
pigmentation in creases of hands
velvety thick lesions in axillae (acanthosis nigrans)
why is there pigmentation and acanthosis nigrans in addisons
melanocyte stimulating hormone is within ACTH (and ACTH is increased)
addisonian crisis diagnostic test
synacthen test (low cortisol)
addisonian crisis treatment (4)
ASAP
hydrocortisone
fludrocortisone
IV saline
IV insulin
why are addisons and type 1 diabetes closely associated
both autoimmune
secondary causes of adrenal insufficiency (2)
problem isnt the adrenal glands
hypopituitarism = low ACTH
iatrogenic from steroids
why do long term steroids cause adrenal insufficiency
if you give steroids you dont need to make steroids = no cortisol reservoir and atrophic adrenal cortex
treatment of secondary adrenal insufficiency
how is this different to addisons (primary adrenal insufficiency)
why
hydrocortisone
no fludrocortisone as aldosterone production is normal (not affected by low ACTH)
what is renin levels in primary adrenal insufficiency
high bc they need to compensate for low aldosterone
are phaeochromocytomas common
no but know for exams
what are extra adrenal phaeochromocytomas called
paragangliomas
histology of phaeochromocytomas
zellballen - cells clustered together
what are phaeochormocytomas known as
the 10% tumour
where are phaeochromocytomas
chromaffin cells of adrenal medulla
% of phaeochromocytomas are bilateral
10%
what do phaeochromocytomas secrete (think about their location)
catecholamines (adrenaline, noradrenaline, dopamine)
% of phaeochromocytomas that are familial
25%
which adrenal problem is associated with;
MEN2a and MEN2b/3, von-hippel-lindau syndrome, neurofibromatosis, tuberose sclerosis
phaeochromocytomas
presentation of phaechromocytoma (lots)
from surges of adrenaline;
headache palpitation tachycardia sweating liable (changing) hypertension anxiety breathlessness constipation
weight loss
what dont paragangliomas secrete that phaeochromocytomas do
dopamine
investigations for phaeochromocytoma (2)
adrenal MRI MIBG scan (areas of high noradrenaline light up)
symptomatic treatment of phaeochromocytoma
alpha blocker THEN beta blocker
why do you give alpha blocker before beta blocker in phaeochromocytoma
other way round may cause blood vessels to constrict = hypertensive crisis
curative treatment of phaeochromocytoma
surgery
chemo
what must you do for everyone with a phaeochromocytoma
family screening
% of phaeochromocytoma that are malignant
10%
which resp condition is associated with cushings
why
asthma
steroid treatment
what controls sodium movement (causes sodium retention)
examples (2)
mineralocorticoid steroids
aldosterone, cortisol
