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 condition includes both 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
• Conn’s syndrome
• Cushing’s syndrome

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 (determines whether high levels of ACTH are from pituitary or ectopic from somewhere else)

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
• inferior petrosal sinus sampling with CRH stimulation
• allows us to figure out if if cortisol production is exogenous or endogenous

Question 17

What can be done right after a low-dose dexamethasone suppression to specify what is causing the increase in endogenous cortisol?

Answer 17

Measure ACTH plasma levels
Low ACTH - Adrenal Adenomas or Adrenal Carcinomas
High ACTH - Cushing Disease (pituitary-dependent) or Ectopic ACTH [IPSS to confirm Ectopic ACTH specfically]

Question 18

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

Answer 18

85%

Question 19

What is pseudo-Cushing’s syndrome?

Answer 19

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

Question 20

List three endogenous causes of Cushing’s syndrome.

Answer 20

Pituitary-dependent Cushing’s disease

Adrenal adenoma

Ectopic ACTH

Question 21

What is this?

Answer 21

Adrenal Glands