Endocrinology (Passmed)

Question 1

Apart from low cortisol and low androgens, What electrolytes imbalances are seen in addisons disease? (4 marks)

Answer 1

Hyperkalaemia
Hyponatraemia
Hypoglycaemia
Metabolic acidosis

Question 2

First line investigation for addisons disease?

Answer 2

Short synacthen test

Question 3

If the cortisol level is still low after the synacthen test, what does that mean?

Answer 3

Problem with adrenal gland

Question 4

If cortisol level is high after synathen test, what does that mean?

Answer 4

Problem with pituitary

Question 5

What is cushings disease?

Answer 5

Pituitary adenoma producing ACTH leads to excessive cortisol production

Question 6

If there is low plasma ACTH but still high cortisol, what does that mean?

Answer 6

Adrenal adenoma

Question 7

If there are high plasma ACTH but low coritsol, what does that mean?

Answer 7

Problem with pituitary gland

Question 8

What is the first line investigation for cushings disease?

Answer 8

Oral dexamethasone test

Question 9

What are the signs of diabetes inspidius?

Answer 9

Polyuria

Excessive thirst

Question 10

What is nephrogenic diabetes insipidus and what causes it?

Answer 10

ADH (anti-diuretic hormone) is being made but the collecting duct in the nephron is not responding to it, causing the urine to be dilute and have large amounts

Caused by hypokalaemia, hypercalcaemia and lithium

Question 11

What is cranial diabetes insipidus and what causes it?

Answer 11

ADH is not being produced by the hypothalamus to prevent polydipsia

Head injury
Brain tumour

Question 12

What is the diagnostic investigation for diabetes insipidus and what is given in this test?

Answer 12

Water deprivation test

Desmopressin acts as synthetic ADH

Question 13

What urine osmolality results would you expect to see in a patient with nephrogenic diabetes insipidus when doing the water deprivation test and then adding desmopressin?

Answer 13

After water depravation - Low

After desmopressin - Low (kidney is still refusing the ADH)

Question 14

What urine osmolality results would you see in cranial diabetes insipidus after the water deprivation test and desmopressin?

Answer 14

After water deprivation - low

After demospressin - high (ADH is now available to stop the kidneys excreting too much water in the urine)

Question 15

What are the symptoms of acromegaly?

Answer 15

• Increased growth in hands
• Increased swelling
• Forehead protrusion
• Bitemporal hemianopia

Question 16

What is the first line investigation for acromegaly?

Answer 16

Screening for insulin like growth factor one (IGF-1)

Question 17

What is the diagnostic / 2nd line investigation for acromegaly?

Answer 17

OGTT and serial GH

Question 18

What does a raised glucose normally do to the levels of GH?

Answer 18

decreases it

Question 19

In acromegaly, what happens to the growth hormone levels under increased glucose?

Answer 19

Increased