ENDO Flashcards
Describe the process of cortisol release
1 - hypothalamus releases CRH (corticotrophin release hormone)
2- anterior pituitary releases ACTH (adrenocorticotrophic hormone)
3 - adrenal gland releases cortisol
How is adrenal insufficiency diagnosed?
Short synacthen test
- administer synthetic ACTH which should induce cortisol rise
- failure of ACTH to rise = Addison’s
How would levels of ACTH differ in primary and secondary adrenal insufficiency?
Primary = high levels (problem is with adrenal glands)
Secondary = low levels (problem with pituitary)
What is Cushing’s disease?
Pituitary adenoma that secretes excessive ACTH
Give 4 causes of Cushing’s syndrome
1- long term steroids
2 - Cushing’s Disease
3 - Adrenal Adenoma
4 - paraneoplastic e.g. small cell lung cancer
How do you diagnose Cushing’s syndrome?
Dexamethasone suppression test
What’s the difference between primary and secondary thyroid disease?
Primary = problem is in thyroids
Secondary = problem in pituitary
Which antibody is most strongly related to Grave’s disease?
TSH receptor antibody
What biochemical picture would you see in someone with subclinical hypothyroidism?
TSH raised but T3, T4 normal
How do you manage subclinical hypothyroidism?
TSH > 10mU/L + normal free thyroxine =
consider offering levothyroxine if TSH level is > 10 mU/L on 2 occasions, 3 months apart
TSH is between 5.5 - 10mU/L + normal free thyroxine =
- if < 65 years consider offering a 6-month trial of levothyroxine AND if TSH level is 5.5 - 10mU/L on 2 separate occasions 3 months apart,and there are symptoms of hypothyroidism
What is a prolactinoma?
BENIGN tumour of pituitary gland
What symptoms of prolactinoma would you get in women? (4)
amenorrhoea
infertility
galactorrhoea
osteoporosis
What symptoms of prolactinoma would you get in men? (3)
impotence
loss of libido
galactorrhoea
How are prolactinomas treated?
DOPAMINE AGONSIT
- cabergoline
- surgery
Give 3 causes of LOW TSH
1 - thyrotoxicosis (with high T4)
2 - secondary hypothyroidism (low T4)
3 - sick euthyroid syndrome (low T4)