Chempath 15: Adrenal Disease Flashcards

1
Q

What are the 3 zones of the adrenal cortex ?

A

Zona glomerulosa
Zona Fasciculata
Zona Reticularis

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2
Q

In which zone of the adrenal cortex is aldosterone produced ?

A

Zona Glomerulosa

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3
Q

In which zone of the adrenal cortex is cortisol produced ?

A

Zona fasciculata

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4
Q

In which zone of the adrenal cortex are androgens such as DHEA produced ?

A

Zona reticularis

DHEA (dehydroepiandosterone) is a precursor to male and female sex hormones including oestrogen and testosterone

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5
Q

Where is adrenaline produced ?

A

Adrenal Medulla

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6
Q

List 2 potential causes of hyperplastic Adrenal glands ?

A
Cushing’s disease 
Ectopic ACTH (e.g lung tumour)
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7
Q

Where does the Right adrenal gland drain into ?

A

Inferior vena cava (IVC)

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8
Q

Where does the left adrenal gland drain into ?

A

Left renal vein

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9
Q

What is schmidt’s syndrome ?

A

A syndrome of co-existing hypothyroidism and Addison’s disease due to autoantibodies against both the thyroid and the adrenals

Hyponatraemia + hyperkalaemia (mineralocorticoid deficiency)
Hypoglycaemia (glucocorticoid (cortisol) deficiency)
low T4 high TSH (Primary hypoparathyroidism)

Aka polyglandular autoimmune syndrome type II

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10
Q

Which test is used to diagnose Addison’s disease ?

A

Short synACTHen test

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11
Q

Explain how the short synACTHen test works and what results you would expect in Addison’s disease ?

A

1)- measure initial cortisol +ACTH
2)- Administer synthetic ACTH 250mcg by IM injection
3)- check cortisol at 30 and 60 mins
In normal people cortisol should be able get to >550 nM within 30 mins

In Addison’s disease Cortisol does increase after synthetic ACTH and stays <10nM

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12
Q

Which test is used to diagnose phaeochromocytoma?

A

Urine catecholamines - high = phaeochromocytoma

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13
Q

What is a phaeochromocytoma ?

A

An adrenal medullary tumour that secretes adrenaline causing hypertension, arrhythmias, sweating, impending sense of doom

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14
Q

List 3 genetic conditions in which phaeochromocytoma is seen?

A

MEN2
Von Hippel Lindau syndrome
Neurofibromatosis type 1

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15
Q

List 3 features of MEN2a?

A

Parathyroid tumours
Medullary thyroid cancer
Phaeochromocytoma

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16
Q

List 4 features of Von Hippel Lindau syndrome ?

A

Phaeochromocytoma
Renal cell carcinoma
Renal cysts
Retinal/CNS haemangioblastomas

17
Q

List up to 6 features of Neurofibromatosis type 1

A
Peripheral and spinal neurofibromas 
Cafe au lait spots
Axillary freckling 
Lisch nodules on iris 
Phaeochromocytoma 
Renal artery stenosis
18
Q

What is Conn’s syndrome ?

A

Primary hyperaldosteronism causing hypertension, hypokalaemia and inhibition of renin secretion

19
Q

Which test can be done to diagnose Conn’s syndrome ?

A

Serum aldosterone: renin levels

Conn’s: high Aldosterone:renin ratio

20
Q

How can you test for Cushing’s ?

A

9am cortisol
12pm midnight cortisol (if low then very strong negative predictive value that it is not Cushing’s)
Low dose dexamethasone suppression test
0.5 mg dexamathasone every 6hrs for 48 hours ( if cortisol not suppressed then Cushing’s)

21
Q

Which tests can help differentiate Cushing’s syndrome from Cushing’s disease?

A

High dose Dexamethasone suppression test- pituitary tumour secreting ACTH shows some suppression in cortisol. Adrenal ACTH tumours are not suppressed.

Inferior petrosal sinus sampling (IPSS)- sampling of the pituitary for an ACTH secreting tumour
85% cause of endogenous Cushing’s syndrome is Cushing’s disease

22
Q

Why is IPSS preferred to High dose dexamethasone suppression test?

A

High dose dexamethasone test has a 20% false positive rate

23
Q

List 3 features of MEN2b ?

A

Phaeochromocytoma
Medullary thyroid cancer
G.I tract mucocutaenous neuromas

24
Q

Differential diagnosis of an adrenal mass

A

Phaeochromocytoma
Conns syndrome
Cushing’s syndrome

25
Q

Treatment for a phaeo

A

Medical emergency
1- alpha blockade (phenoxybenzamine)
Leads to sudden BP drop so give fluids

2- beta blockade
To treat reflex tachycardia

Surgery

26
Q

What is pseudo Cushing’s syndrome

A

Obesity can change your metabolism of cortisol and produce a picture that looks like Cushings

27
Q

List the endogenous and exogenous causes of Cushing’s syndrome

A
Endogenous 
Pituitary dependent Cushing’s disease (85%) 
Adrenal adenoma (10%) 
Ectopic ACTH ( 5%) 

Exogenous
Oral steroids