Obesity

Question 1

What is the expected response of a normal subject to the dexamethasone suppression test?

Answer 1

Reduction in cortisol levels following the low dose dexamethasone suppression test

Question 2

What is the expected response of an individual with Cushing’s disease to the dexamethasone suppression test?

Answer 2

No reduction in cortisol output following the low dose dexamethasone suppression test, but inhibition of output following the high dose test

Question 3

What is the expected response of an individual with an adrenal tumour/ ectopic ACTH secretion to the dexamethasone suppression test?

Answer 3

No reduction in steroid production after high or low dexamethasone suppression test

Question 4

Name the 3 principle arteries that supply the adrenal gland.

Answer 4

1. Superior suprarenal artery arising from the inferior phrenic artery
2. Middle suprarenal artery arising directly from the abdominal aorta
3. Inferior suprarenal artery arising from the renal artery

Question 5

Why are the adrenal glands such a common site of metastases/ site of TB infection?

Answer 5

Most vascular tissue in the body gram for gram

Question 6

What % of adult Cushing’s syndrome is made of patients with Cushing’s disease?

Answer 6

70% of adults with Cushing’s

Question 7

What is Cushing’s disease?

Answer 7

ACTH secreting pituitary adenoma

Question 8

Name 3 other medical conditions that may cause a ‘false positive’ raise in urinary free cortisol levels during investigation for Cushing’s disease

Answer 8

1. Obesity
2. Polycystic ovarian syndrome
3. Depression

Question 9

Compare the key electrolyte imbalances seen in Cushing’s syndrome and Addison’s disease respectively

Answer 9

1. Cushing’s syndrome - Hypokalaemia and hypernatraemia

2. Addison’s disease - Hyperkalaemia and hyponatraemia

Question 10

What is the mainstay of initial treatment for adrenal crisis? (2)

Answer 10

1. High dose replacement hydrocortisone - 100mg IV every 6 hours
2. IV saline - 2-3L first hour, then 3-4 L per day

Question 11

Name the hormones released by the posterior pituitary gland

Answer 11

1. Oxytocin

2. ADH

Question 12

Name the hormones released by the anterior pituitary gland

Answer 12

1. TSH
2. GH
3. ACTH
4. FH and LH
5. PRL
6. Endorphins

Question 13

What are the 3 principle causes of SIADH?

Answer 13

1. Lung diseases - cancer or pneumonia
2. Brain lesions - tumours, head injury, bleed or stroke
3. Drugs e.g. carbamazepine or SSRIs

Question 14

What is Metyrapone

Answer 14

A cortisol synthesis inhibitor that can be used in the treatment of Cushing’s syndrome

Question 15

Which test would allow discrimination between pituitary and an ectopic source of excess ACTH?

Answer 15

Inferior petrosal sinus sampling

Question 16

Which enzyme does Metyrapone inhibit?

Answer 16

11 beta- hydroxylase