Physiology - Adrenal Flashcards
name the 3 layers from outer to inner of the cortex part of the adrenal gland
zona glomerulosa
zona fasiculata
zona reticularis
what does the following zones secrete:
(a) zona glomerulosa
(b) zona fasiculata
(c) zona reticularis
(a) zona glomerulosa - ALDOSTERONE
(b) zona fasiculata - CORTISOL
(c) zona reticularis - ANDROGENS
what does the medulla secrete?
catecholamines - epinephrine and norepinephrine
the zone reticularis is where the majority of androgens are made in females but the majority of the production in males is in the what?
testes
aortisol and androgen production are regulated by hormones produced by…
hypothalamus and anterior pituitary gland
aldosterone regulated by…
renin-angiotensin system and plasma potassium
cortisol exerts negative feed back on the hypothalamus and the anterior pituitary to halt the production of what respectively?
CRH and ACTH
what is the major regulator of aldosterone production?
renin
what is renin and so aldosterone activated in response to?
low blood pressure
what does angiotensin cause?
direct vasoconstriction
what does aldosterone do?
elevate BP
3 principle uses of corticosteroids?
suppress inflammation
suppress immune response
replacement treatment
3 disease in which corticosteroids are used?
asthma
arthritis, UC and crohns
malignant disease
21 year old female
‘unwell’ for few months
Weight loss
Amenorrhoea
Acutely unwell over past 48 hours with vomiting and diarrhoea
On examination:
Dark skin Dehydrated Hypotensive low Na = hyponatraemia high K = hyperkalaemia
diagnosis?
Addisons disease
primary adrenal insufficiency can be causes by what 3 things?
Addisons disease
congenital adrenal hyperplasia (CAH)
adrenal TB/malignancy
secondary adrenal insufficiency can be causes by what 3 things?
lack of ACTH stimulation
excess exogenous steroid
pituitary/hypothalmic disorder
is Addisons autoimmune?
yes
how much of the adrenal Gand is destroyed before you are symptomatic in Addisons?
> 90%
what other autoimmune diseases is associated with Addisons?
T1DM
thyroid disease
pernicious anaemia
clinical features of Addisons disease?
anorexia weight loss fatigue/lethargy dizzy low BP abdominal pain D&V skin pigmentation
name the 3 points to a suspicious biochemistry of Addisons disease
low sodium
low glucose
high potassium
low blood volume
what test is performed to diagnose Addisons?
short synacthen test
ACTH high or low in Addisons?
high = causes skin pigmentation
renin and aldosterone high or low in Addisons?
renin = high
aldosterone = low
are adrenal autoantibodies important in addisons? if so, what one?
yes - 21-OH antibody
is management of Addisons urgent?
yes - DO NOT DELAY TREATMENT!
Addisons immediate management?
hydrocortisone as cortisol replacement
fludrocortisone as aldosterone replacement
= STEROIDS AND FLUID
what do those with Addisons due to pituitary/hypothalmic disease tumours and/or exogenous steroid use not need as treatment?
mineralocorticoid as that is under renin-aldo mechanism control
do you see hyperpigmentation in those with SECONDARY adrenal insufficiency?
no - skin pale as no high ACTH
how is secondary Addisons treated?
hydrocortisone replacement
fludrocortisone unnecessary
17 year old female
3 year history of:
Central weight gain Acne Amenorrhoea Hypertension Severe osteoporosis Proximal muscle weakness (myopathy)
cushing’s syndrome
what is there an excess of in cushings?
cortisol
what sex is cushings more common in?
female
clinical features of cushings
easy bruising
facial plethora
striae
proximal myopathy
what can be either ACTH dependent or independent?
cushings
cushings disease is ACTH dependent
true or false?
true - cushings disease is due to a pituitary adenoma
ACTH dependent or independent:
adrenal adenoma
ACTH independent
ACTH dependent or independent:
adrenal carcinoma
ACTH independent
ACTH dependent or independent:
ectopic ACTH
ACTH dependent
ACTH dependent or independent:
ectopic CRH
ACTH dependent
ACTH dependent or independent:
nodular hyperplasia
ACTH independent
name the 3 tests to confirm if there is cortisol excess
overnight dexamethasone suppression test
24 hour urinary free cortisol
late night salivary corisol
state the diagnostic test for cushings
low dose dexamethasone suppression test
what is the commonest cause of cortisol excess?
iatrogenic - steroid use
pituitary ACTH is chronically suppressed
can you suddenly stop the steroids the is causing cushings?
no!
what endocrine disorders cause hypertension?
too much mineralocorticoid (aldosterone)
adrenalin secreting tumour
acromegaly - too much GH
too much glucocorticoid (cortisol)
34 year old male
1 year history of hypertension
Renal function normal but plasma potassium low
diagnosis?
primary aldosteronism
hypertension + hypokalaemia = ?
primary aldosteronism/mineralocorticid excess
autonomous production of aldosterone independent of its regulators (angiotensin II/potassium) defines what?
primary aldosteronism
regarding primary aldosteronism, what is vanishingly rare?
renin producing tumour - secondary cause
name the drug that is a mineralocorticoid receptor antagonist
spironolactone
does aldosterone increase or decrease BP?
increase
aldosterone causes sodium retention
true or false?
true
name the most common cause of secondary hypertension
primary aldosteronism
significant hypertension
hypokalaemia
alkalosis
diagnosis?
primary aldosteronism
name the 3 subtypes of primary aldosteronism
adrenal adenoma - ‘conns’ - 30%
bilateral adrenal hyperplasia - commonest - 60%
unilateral hyperplasia - rare
stages in diagnosis of primary aldosteronism
confirm aldosterone excess
confirm subtype - CT
high aldosterone + low renin = ?
PA
management of PA due to adrenal adenoma?
unilateral laparoscopic adrenalectomy
PA due to bilateral adrenal hyperplasia drug treatment?
spironolactone
name the commonest deficiency in congenital adrenal hyperplasia
21alpha hydroxylase
21alpha hydroxylase deficiency is autosomal what?
autosomal recessive
those with congenital adrenal hyperplasia are Isabel to produce what 2 things?
aldosteronism and cortisol
what do you measure to diagnose congenital adrenal hyperplasia?
17-OH progesterone
is 17-OH progesterone high or low in CAH?
high
what is the classical presentation of CAH in:
(a) males
(b) females
(a) males - adrenal insufficiency and poor weight gain
(b) females - genital ambiguity
on classical - hirsute, acne, oligomenorrhoea, precocious puberty, infertility
CAH drug treatment?
glucocorticoid (cortisol) replacement
hydrocortisone and fluids as crisis
what is synthesised from tyrosine via dopamine?
adrenaline
28 year old female
1998 - dyspnoea and palpitations with poor LV function
1999 - pregnant with deteriorating cardiac function - BP - 154/110
high noradrenaline
low adrenaline
high dopamine
diagnosis?
paraganglioma
labile hypertension
postural hypotension
paroxsymal sweating, headache, pallor and tachycardia
the above are a triad of clues for what?
phaeochromocytoma
a tumour in the adrenal medulla is called a what?
phaeochromocytoma
a tumour that is extra adrenal (sympathetic chain is called a what?
paraganglioma
phaeochromocytoma is the __% tumour
phaeochromocytoma is the 10% tumour
chromaffin cells reduce chrome salts to metal chromium resulting in a _____ colour reaction
chromaffin cells reduce chrome salts to metal chromium resulting in a BROWN colour reaction
phaeochromocytoma is a ________ form of hypertension
phaeochromocytoma is a CURABLE form of hypertension
hypertension
headache
sweating
the above 3 is the classical triad for what condition?
phaeochromocytoma
what do you test to confirm catecholamine excess in phaeochromocytoma?
urine
2x24hour catecholamines or metanephrins in acid containing bottles
phaeochromocytoma drug therapy?
alpha blocker - Phenoxybenzamine
THEN
beta-blocker - Propranolol
fluid and/or blood replacement
other phaeochromocytoma treatment?
surgical excision
chemo if malignant
radio labelled MIBG
SDHB = B is for ___
SDHD = D is for ___
SDHB = B is for BAD
SDHD = D is for DAD
