Disorders of Adrenocortical Dysfunction

Question 1

What makes up the adrenal gland?

Answer 1

The cortex around the outside (glandular) and the Medulla on the inside (modified neuronal ganglia) but instead of synapsing onto other nerves, it synapses onto blood vessels.

Question 2

What does the Cortex produce?

Answer 2

Glucocorticoids e.g. cortisol
Mineralocoritcoids e.g. aldosterone
Sex steroids e.g. testosterone

Question 3

What does the medulla produce?

Answer 3

Epinephrine and norepinephrine

Question 4

What are the three areas of the cortex from outside to inside?

Answer 4

Zona glomerulosa - aldosterone
Zona fasciculata - cortisol
Zona reticularis - testosterone

Question 5

What does cortisol do?

Answer 5

Increases plasma glucose levels

• Inc gluconeogenesis
• Dec glucose utilisation
• Inc glycogenesis
• Inc glycogogen storage

Increases lipolysis - provides energy

Proteins are catabolised - releases amino acids

Na+ and H20 retention - maintains BP

Anti inflammatory

Increases gastric acid production

Question 6

What is Cushing’s Syndrome?

Answer 6

(Chronic exposure to) excessive levels of cortisol in the blood

Question 7

What is Cushing’s Disease?

Answer 7

Excess cortisol in the blood due to an ACTH secreting pituitary tumour

Question 8

What are the clinical features of Cushing’s syndrome due to changes in protein and fat metabolism?

Answer 8

Change in body shape
Central obesity
Moon face
Buffalo hump
Thin skin, easy bruising
Osteoporosis
Diabetes
Purple stretch marks

Question 9

What are the clinical features of Cushing’s syndrome due to changes in sex hormones?

Answer 9

Excessive hair growth
Irregular periods
Problems conceiving
Impotence

Question 10

How to diagnose Cushing’s?

Answer 10

Urinary free cortisol
Diurnal rhythm
Overnight dexamethasone suppression testing - if cortisol present, the person has Cushing’s syndrome.

Question 11

What are the different diagnoses possible?

Answer 11

True Cushings’s syndrome

Pseudo-Cushing’s Syndrome - stress related, increased cortisol levels

• Depression
• Alcoholism
• Anorexia Nervosa
• Obesity

Exogenous steroids

Question 12

What are the different causes of increased cortisol levels that can be diagnosed?

Answer 12

Cushing’s Disease - producing ACTH
-Pituitary Adenoma

Adrenal Tumour - Producing Cortisol

• Benign
• Malignant

Ectopic ACTH production

• Benign
• Malignant

Question 13

When do you use high dose dexamethasone?

Answer 13

Differentiating the cause of the syndrome.

If cortisol suppresses to < 50% of baseline then the patient has Pituitary-dependent Cushing’s Disease

If the Cortisol does not suppress then the patient has ectopic ACTH production or an adrenal tumour

Question 14

Features of cortisol excess?

Answer 14

Hypokalaemia
Metabolic alkalosis
Hyperglycemia