Endocrinology

Question 1

Where is thyrotropin-releasing hormone released from?

Answer 1

Hypothalamus

Question 2

What releases thyroid-stimulating hormone?

Answer 2

Pituitary gland

Question 3

What would TFTs show in primary hyperthyroidism?

Answer 3

High T4 and T3

Low TSH

Question 4

What would TFTs show in secondary hyperthyroidism?

Answer 4

High T4 and T3

High TSH

Question 5

What would TFTs show in primary hypothyroidism?

Answer 5

Low T4 and T3

High TSH

Question 6

What would TFTs show in secondary hypothyroidism?

Answer 6

Low T4 and T3

Low TSH

Question 7

What can be the cause of abnormal TFTs in a patient with an acute illness?

Answer 7

Sick euthyroid syndrome

Question 8

What would TFTs show in sick euthyroid syndrome?

Answer 8

Low T4 and T3

Low/normal TSH

Question 9

What releases corticotropin-releasing hormone and what does it stimulate release of?

Answer 9

Hypothalamus

Stimulates release of ACTH from pituitary

Question 10

What does ACTH do?

Answer 10

Acts on adrenal cortex to release glucocorticoids

Question 11

What causes Cushing syndrome?

Answer 11

Excess glucocorticoids

Question 12

What are some endogenous causes of Cushing syndrome?

Answer 12

Primary adrenal disease - adrenal tumour

ACTH excess - Cushing disease, ACTH-producing tumour

Question 13

What will the ACTH level be in Cushing syndrome caused by primary adrenal disease?

Answer 13

Low ACTH

Question 14

What will the ACTH level be in secondary hyperadrenalism?

Answer 14

Normal/High ACTH

Question 15

What are the four methods used to diagnose Cushing syndrome?

Answer 15

Measure free cortisol in 24-hour urine collection
Measure cortisol in late-night salivary sample
Perform 1mg overnight dexamethasone suppression test
Perform 2mg 48-hour dexamethasone suppression test

Question 16

What will cortisol and ACTH levels show in primary hypoadrenalism (e.g. Addison’s disease)?

Answer 16

Low cortisol

High ACTH

Question 17

What will cortisol and ACTH level show in secondary hypoadrenalism?

Answer 17

Low cortisol

Low ACTH

Question 18

What test can used to assess hypoadrenalism?

Answer 18

Short Synacthen Test

Question 19

What will the result of the Synacthen test be in primary hypoadrenalism?

Answer 19

Poor rise in cortisol levels (less than 600nmol/l 30 mins after Synacthen administered)

Question 20

What will the result of the Synacthen test be in secondary hypoadrenalism?

Answer 20

Result will be normal

Question 21

What are the two forms of diabetes insipidus?

Answer 21

Cranial

Nephrogenic

Question 22

What would ADH levels be in cranial diabetes insipidus and why?

Answer 22

Low ADH - problem with release of ADH from hypothalamus

Question 23

What would ADH levels be in nephrogenic diabetes insipidus and why?

Answer 23

Normal/High ADH - failure to exert effect on kidney

Question 24

What are the common causes of SIADH?

Answer 24

Intrathoracic causes - infection, tumour
Intracranial causes - infection, tumour, head injury
Medications - carbamazepine, antipsychotics

Question 25

What are common causes of hyperprolactinaemia?

Answer 25

Physiological - pregnancy, lactation
Prolactin-secreting tumour
Medications - phenothiazine antipsychotics, most antiemetics
PCOS
Following a seizure
Primary hypothyroidism