ChemPath: Adrenal Disease

Question 1

What are the five layers of the adrenal gland?

Answer 1

• Capsule
• Glomerulosa
• Fasciculata
• Reticularis
• Medulla

Question 2

What can cause adrenal glands to appear wasted?

Answer 2

Addison’s disease

Long-term steroid use

Question 3

What can cause adrenal glands to become hyperplastic?

Answer 3

Cushing’s disease

Ectopic ACTH

Question 4

By what factor is the output of cortisol from the adrenals greater than the output of aldosterone?

Answer 4

About 1000 (aldosterone is measured in picomoles, cortisol is measured in nanomoles)

Question 5

How many arteries and veins do the adrenal glands have?

Answer 5

57 small arteries

1 vein

Question 6

How is a blood sample to measure adrenal output taken?

Answer 6

A cannula is placed through the IVC into the adrenal vein

Question 7

How is the venous drainage different for the left and right adrenal glands?

Answer 7

Left - drains into the left renal vein

Right - drains directly into the IVC

Question 8

What is the term used to describe the co-existence of primary hypothyroidism and Addison’s disease?

Answer 8

Schmidt syndrome (though it is now called Polyglandular Autoimmune Syndrome Type 2)

Question 9

Describe the short synacthen test.

Answer 9

• Measure cortisol and ACTH at the start of the test
• Administer 250µg synthetic ACTH by IM injection
• Check cortisol at 30 and 60 mins
• Healthy people should produce >550nM of cortisol within 30 mins

Question 10

What is the differential diagnosis for hypertension with an adrenal mass?

Answer 10

• Phaeochromocytoma - adrenal medullary tumour secreting adrenaline
• Conn’s syndrome - adrenal tumour secreting aldosterone
• Cushing’s syndrome - secretes cortisol

Question 11

What are the disastrous consequences of phaeochromocytoma?

Answer 11

• Severe hypertension
• Arrhythmia
• Death

Question 12

Outline the treatment of phaeochromocytoma.

Answer 12

• Urgent alpha blockade (with phenoxybenzamine or phentolamine or doxazocin)
• Some fluids may be given after the alpha-blocker to prevent reflex tachcardia
• A beta-blocker should be given after the alpha-blocker to prevent reflex tachycardia
• Patients should receive high-dose alpha and beta-blockade before surgery as the action of surgery can cause the release of catecholamines from the adrenals

Question 13

Name three genetic syndromes associated with phaeochromocytomas.

Answer 13

• MEN2
• Von Hippel Lindau syndrome
• Neurofibromatosis type 1

Question 14

Describe the levels of aldosterone and renin in Conn’s syndrome.

Answer 14

High aldosterone

Low renin

Question 15

List some tests used in Cushing’s syndrome.

Answer 15

• 9am cortisol
• Midnight cortisol
• Low-dose dexamethasone suppression test
• Inferior petrosal sinus sampling - measure the ACTH

85% of cases are due to cushings disease - pituitary adenoma

Question 16

Describe how low-dose dexamethasone suppression test is performed.

Answer 16

• The patient’s baseline ACTH and cortisol is measured at the start
• Then they are given 0.5mg dexamethasone every 6 hours for 48 hours
• This should suppress cortisol to <50nM
• If there is failure of suppression of cortisol, the patient should be sent for inferior petrosal sinus sampling

Question 17

What proportion of endogenous Cushing’s syndrome is caused by Cushing’s disease?

Answer 17

85%

cushing’s disease - pituitary dependent

Question 18

What is pseudo-Cushing’s syndrome?

Answer 18

Obesity can change your metabolism of cortisol to produce a clinical syndrome that looks like Cushing’s syndrome

cortisol suppressed by low-dose dexamethasone test - normal

Question 19

List three endogenous causes of Cushing’s syndrome.

Answer 19

Pituitary-dependent Cushing’s disease - adenoma secreting ACTH

Adrenal adenoma

Ectopic ACTH

Question 20

What is this?

Answer 20

Adrenal Glands

Question 21

Treatment following adrenalectomy for Cushing’s syndrome

Answer 21

exogenous glucocorticoid

slowly reduce the prednisolone over a year - gives adrenal gland time to start working

patient will not feel good during steroid weaning