ChemPath: Adrenal Disease

Question 1

Patient tired and vomiting. TSH>50 and free T4 <5. What does this result suggest?

Answer 1

Primary hypothyroidism

Question 2

What region of the adrenal gland makes cortisol?

Answer 2

zona fasciculata

Question 3

What are the five layers of the adrenal gland?

Answer 3

• Capsule
• Glomerulosa
• Fasciculata
• Reticularis
• Medulla

Question 4

What is Addison’s disease?

Answer 4

adrenal failure

Question 5

What can cause adrenal glands to appear wasted?

Answer 5

Addison’s disease

Long-term steroid use

Question 6

What can cause adrenal glands to become hyperplastic?

Answer 6

Cushing’s disease

Ectopic ACTH

Question 7

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

Answer 7

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

Question 8

How many arteries and veins do the adrenal glands have?

Answer 8

57 small arteries

1 vein

Question 9

How is a blood sample to measure adrenal output taken?

Answer 9

A cannula is placed through the IVC into the adrenal vein

Question 10

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

Answer 10

Left - drains into the left renal vein

Right - drains directly into the IVC

Question 11

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

Answer 11

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

Question 12

Describe the short synacthen test.

Answer 12

• 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 13

synACTHen results in patient with Addison’s

Answer 13

ACTH >100ng/dl

cortisol <10nM at both 30 and 60 min

Question 14

What is a phaeochromocytoma?

Answer 14

adrenal medullary tumour secreting adrenaline

Question 15

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

Answer 15

• Phaeochromocytoma
• Conn’s syndrome
• Cushing’s syndrome

Question 16

What is Conn’s syndrome?

Answer 16

Adrenal tumour secreting aldosterone

Question 17

How can Conn’s syndrome be diagnosed?

Answer 17

High aldosterone: renin ratio as high blood pressure suppresses renin secretion

Question 18

How can Conn’s syndrome be managed?

Answer 18

total adrenalectomy and spironolactone

Question 19

What are the disastrous consequences of phaeochromocytoma?

Answer 19

• Severe hypertension
• Arrhythmia
• Death

Question 20

Outline the treatment of phaeochromocytoma.

Answer 20

• Urgent alpha blockade (phenoxybenzamine or doxazocin or phentolamine)
• Some fluids may be given after the alpha-blocker to prevent reflex tachycardia
• 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 21

Name three genetic syndromes associated with phaeochromocytomas.

Answer 21

• MEN2
• Von Hippel Lindau syndrome
• Neurofibromatosis type 1

Question 22

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

Answer 22

High aldosterone

Low renin

Question 23

List some tests used in Cushing’s syndrome.

Answer 23

• 9am cortisol
• Midnight cortisol: take within 90 seconds
• Low-dose dexamethasone suppression test
• Inferior petrosal sinus sampling

Question 24

Describe how low-dose dexamethasone suppression test is performed and results.

Answer 24

• 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 25

Low dose dexamethasone test comes back positive. What conclusion can you draw from this?

Answer 25

This person has Cushing’s syndrome of indeterminate cause.

Question 26

What is inferior petrosal sinus sampling?

Answer 26

IPSS with CRH stimulation-→ cannula to pituitary glands into pituitary veins and ACTH levels measured- if very high= pituitary dependent

Question 27

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

Answer 27

85%

Question 28

Exogenous causes of Cushing’s syndrome

Answer 28

Oral steroids

Herbal remedies containing steroids

Question 29

What is pseudo-Cushing’s syndrome?

Answer 29

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

Question 30

List three endogenous causes of Cushing’s syndrome.

Answer 30

85% Pituitary-dependent Cushing’s disease

10% Adrenal adenoma

5% Ectopic ACTH

Question 31

What is this?

Answer 31

Adrenal Glands