Physiology - Adrenal Flashcards by Matthew Turnbull

name the 3 layers from outer to inner of the cortex part of the adrenal gland

zona glomerulosa
zona fasiculata
zona reticularis

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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

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what does the medulla secrete?

catecholamines - epinephrine and norepinephrine

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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

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aortisol and androgen production are regulated by hormones produced by…

hypothalamus and anterior pituitary gland

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aldosterone regulated by…

renin-angiotensin system and plasma potassium

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cortisol exerts negative feed back on the hypothalamus and the anterior pituitary to halt the production of what respectively?

CRH and ACTH

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what is the major regulator of aldosterone production?

renin

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what is renin and so aldosterone activated in response to?

low blood pressure

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what does angiotensin cause?

direct vasoconstriction

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what does aldosterone do?

elevate BP

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3 principle uses of corticosteroids?

suppress inflammation
suppress immune response
replacement treatment

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3 disease in which corticosteroids are used?

asthma

arthritis, UC and crohns

malignant disease

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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

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primary adrenal insufficiency can be causes by what 3 things?

Addisons disease

congenital adrenal hyperplasia (CAH)

adrenal TB/malignancy

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secondary adrenal insufficiency can be causes by what 3 things?

lack of ACTH stimulation

excess exogenous steroid

pituitary/hypothalmic disorder

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is Addisons autoimmune?

yes

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how much of the adrenal Gand is destroyed before you are symptomatic in Addisons?

> 90%

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what other autoimmune diseases is associated with Addisons?

T1DM
thyroid disease
pernicious anaemia

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clinical features of Addisons disease?

anorexia
weight loss
fatigue/lethargy
dizzy
low BP
abdominal pain
D&amp;V
skin pigmentation

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name the 3 points to a suspicious biochemistry of Addisons disease

low sodium
low glucose
high potassium

low blood volume

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what test is performed to diagnose Addisons?

short synacthen test

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ACTH high or low in Addisons?

high = causes skin pigmentation

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renin and aldosterone high or low in Addisons?

renin = high

aldosterone = low

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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 = ?

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