Hyperadrenalism

Question 1

What is the difference between Cushing’s disease and Cushing’s syndrome?

Answer 1

Disease: a tumour on pituitary gland causes excess production of ACTH

Syndrome: when the body has abnormally high levels of cortisol

Question 2

What are some causes of Cushing’s syndrome?

Answer 2

Cushing’s disease

Synthetic steroids given as a treatment for another condition

Ectopic: small cell lung cancer or carcinoid tumours can sometimes secrete ACTH

Adrenal tumour / cancer

Question 3

What is ACTH?

Answer 3

AdrenoCorticoTropic hormone

Produced and secreted by the anterior pituitary gland

It acts on the adrenal glands to stimulate release of cortisol

Question 4

On what part of the adrenal gland does ACTH act?

Answer 4

Zona fasciculata of cortex of adrenal gland

CORTisol is made in the CORTex

Question 5

Clinical features of Cushing’s?

Answer 5

Start from head and move down

Anxious, mood disturbance, labile
Moon face, red plethoric face
Thinning hair and skin (bruising)
Buffalo hump
Hypertension
Central obesity
Striae
Hirsutism
Oligomenorrhoea / erectile dysfunction
Recurrent infections
Peripheral muscle weakness
Osteopenia, pathological fractures

Question 6

What investigations would you do for Cushing’s?

Answer 6

Bloods: raised WCC, hypokalaemia, plasma ACTH

24 hour urine free cortisol: collect up urine, see if higher than normal

Midnight serum or salvia cortisol

Low dose dexamethasone suppression test 1mg
High dose dexamethasone suppression test 8mg

MRI brain to look for pituitary adenoma

Question 7

Describe the dexamethasone suppression tests?

Answer 7

Give a dose of dexamethasone (1mg low dose, 8mg high dose)

1mg / 8mg dexamethasone at 11pm, high cortisol at 8am suggests ectopic ACTH

In a healthy person dex should suppress levels of cortisol in the body
In a person with Cushing’s syndrome it won’t be supressed

Question 8

Management of Cushing’s?

Answer 8

Depends on cause!

Treat underlying cause

• withdraw medication
• remove tumour

If unable, like in a small cell lung cancer use cortisol synthesis inhibitors - metyrapone

Question 9

Prognosis of Cushing’s?

Answer 9

If treated, good

But if not, vascular problems like hypertension cause problems

Question 10

How do steroids used as medication cause Cushing’s syndrome?

Answer 10

They cause excess hypothalamus action

So excess pituitary, so excess adrenal production of cortisol

Question 11

What is meant by ectopic ACTH production?

Answer 11

When cancers like carcinoid tumours or small cell lung cancers release ACTH

Question 12

What are the functions of cortisol?

Answer 12

‘The stress hormone’

Promotes breakdown of fat

Pancreas: counteracts insulin

Liver: triggers gluconeogenesis

Bone: reduces bone formation

Reduces immune response

Question 13

Define Cushing’s syndrome?

Answer 13

Persistently and inappropriately elevated circulating cortisol in the blood

Question 14

Why does Cushing’s cause abdominal obesity and thin arms and legs?

Answer 14

Cortisol causes deposition of fat around viscera but not subcutaneously

Thin limbs due to this and protein catabolism caused by cortisol

Question 15

What are the fancy names for the main causes of these:

• hypercortisolism
• hyperaldosteronism?

Answer 15

Hypercortisolism: Cushing’s

Hyperaldosteronism: Conn’s

Question 16

What is Conn’s syndrome?

Answer 16

Inappropriate excess production of aldosterone caused by an adrenal adenoma secreting aldosterone

Causes retention of water and sodium and loss of potassium

Question 17

What’s the difference between primary and secondary hyperaldosteronism?

Answer 17

Primary: inappropriately high secretion of aldosterone independent of RAAS

Secondary: high aldosterone due to high renin levels

Question 18

What happens in primary hyperaldosteronism, in terms of water, sodium and potassium? Why?

Answer 18

Excessive reabsorption and thus retention of water and Na
Loss of K

Because aldosterone’s usual function is to cause reabsorption of water and Na back into blood, and to secrete K, so when there’s too much, this system goes crazy

Question 19

Clinical features of Conn’s syndrome?

Answer 19

Hypertension due to excessive retention of water

Signs of hypernatraemia and hypokalaemia
Headaches, lethargy, weakness

Question 20

Give some causes of primary hyperaldosteronism?

Answer 20

Conn’s syndrome: caused by an adrenal adenoma

Bilateral adrenal hyperplasia

Adrenal carcinoma

Question 21

Investigations of Conn’s syndrome?

Answer 21

Raised plasma aldosterone

CT/MRI to see if adenoma or hyperplasia

ECG to ensure no cardiac effects of hypokalaemia

Question 22

Management of Conn’s syndrome?

Answer 22

Surgical removal of adenoma

Question 23

Management of bilateral adrenal hyperplasia?

Answer 23

Aldosterone antagonist: spironolactone

Question 24

What is spironolactone?

Answer 24

A drug, an aldosterone antagonist