1b Pituitary Tumours

Question 1

What is a functioning tumour of the somatotrophs called?

Answer 1

Acromegaly

Question 2

what is the most common pit adenoma

Answer 2

Gonadatrophs, prolactinomas, GH

Question 3

Why are prolactinomas in men bigger?

Answer 3

Less likely do present earlier - women looses her menses and produces more breast milk

Question 4

What is a functioning tumour of the thyrotrophs called?

Answer 4

TSHoma

Question 5

What is a functioning tumour of the lactotrophs called?

Answer 5

prolactinoma

Question 6

What is a functioning tumour of the gonadotrophs called?

Answer 6

gonadotrophinoma

Question 7

What is a functioning tumour of the Corticotrophs called?

Answer 7

Cushings Disease

Question 8

What is a functioning tumour of the corticotrophs called?

Answer 8

Corticotroph adenoma

Question 9

What is the name for a radiologically small and large pituitary tumour?

Answer 9

Microadenoma and macroadenoma

Question 10

What are the two functional classifications for tumours?

Answer 10

excess hormone secretion or not (non-functioning adenoma

Question 11

Are pituitary tumours generally malignant?

Answer 11

No

Question 12

Describe how hyperprolactinaemia leads to the associated symptoms?

Answer 12

Prolactin binds to prolactin
receptors on kisspeptin
neurons in hypothalamus

Inhibits kisspeptin release.

Decreases in downstream
GnRH/LH/FSH/T/Oest
Oligo-amenorrhoea/Low
libido/Infertility/Osteoporosis

Question 13

What is serum prolactin proportional to in prolactinomas?

Answer 13

The size of the tumour

Question 14

What is the hormonal presentation of prolactinomas?

Answer 14

low GnRH, low FSH and low LH

Question 15

What are the clinical symptoms of prolactinoma?

Answer 15

Menstrual disturbance
* Erectile dysfunction
* Reduced libido
* Galactorrhoea
* Subfertility

Question 16

What is Galactorrhoea?

Answer 16

Breasts producing milk outside pregnancy

Question 17

why is Galactorrhoea more common in women?

Answer 17

Need oeastrogen to prime the breats for lactation

Question 18

What are three physiological causes of elevated prolactin

Answer 18

• Pregnancy/breastfeeding
• Stress: exercise, seizure, venepuncture
• Nipple/chest wall stimulation

Question 19

Why is prolactin levels higher in pregnancy?

Answer 19

Lactotrophs undergo hypertrophy

Question 20

What are the pathological causes of elevated prolactin?

Answer 20

• Primary hypothyroidism - stimulates prolactin
• Polycystic ovarian syndrome
• Chronic renal failure - cannot destroy prolactin

Question 21

Why does primary hypothyroidism cause elevated prolactin?

Answer 21

thyroid gland not working, therefore not producing thyroxine, so TSH rises which stimulates prolactin release

Question 22

How should a prolactinoma be investigated?

Answer 22

MRI - look for pituitary tumour

Question 23

What is the first line treatment of prolactinoma?

Answer 23

Cabergoline - dopamine receptor agonist

Question 24

How do dopamine receptor agonists reduce prolactin and shrink prolactinomas?

Answer 24

Dopamine is the off switch for prolactin, therefore dopamine binds to the D2 receptors on the lactotrophs and reduces prolactin production - can also used dopamine agonists like Cabergoline

Question 25

Where does the dopamine come from?

Answer 25

The dopaminergic neurones

Question 26

What is the difference between acromegaly and giganticism?

Answer 26

acromegaly is in adults, gigantism in children

Question 27

What is the problem with insidious prsentation of acromegaly?

Answer 27

long time between symptoms appearing and mean time to diagnosis

Question 28

What are some clinical symptoms of acromegaly?

Answer 28

Sweatiness * Headache * Coarsening of facial features * Macroglossia * Prominent nose * Large jaw - prognathism * Increased hand and feet size * Snoring & obstructive sleep apnoea * Hypertension * Impaired glucose tolerance/diabetes mellitus

Question 29

What are the two mechanisms of growth hormone action?

Answer 29

direct and indirect Direct = growth hormones acting on tissues Indirect = GH act on liver, which makes IGF-1 which then acts on other body tissues

Question 30

How do you diagnose acromegaly?

Answer 30

Failed suppression (‘paradoxical rise’) of GH following oral glucose load – oral glucose tolerance test then MRI

Question 31

Why are random measurements of growth hormone not useful?

Answer 31

GH is pulsatile so random measurements are unhelpful

Question 32

Why is it important that acromegaly must be treated?!!!!!!

Answer 32

Increased cardiovascular risk in untreated acromegaly

Question 33

What is the first line treatment of acromegaly?

Answer 33

First-line treatment is surgical – trans-sphenoidal pituitary surgery

Question 34

what is the medical treatment to do before surgery for treating acromegaly?(2)

Answer 34

Somatostatin analogues eg octreotide – ‘endocrine cyanide’ Dopamine agonists eg cabergoline (GH secreting pituitary tumours frequently express D2 receptors)

Question 35

What are the clinical features of Cushings?

Answer 35

- Red Striae - Buffalo humps - Lemon on sticks - centripedal obesity - Moon face - Proximal Myopathy - cannot get up from squat - Easily bruising

Question 36

What us Cushings Syndrome?

Answer 36

Too much cortisol

Question 37

What are the common causes of Cushings Syndrome?

Answer 37

Causes of Cushing’s syndrome * Taking steroids by mouth (common) * Pituitary dependent Cushing’s disease (pituitary adenoma) * Ectopic ACTH (lung cancer) * adrenal adenoma or carcinoma

Question 38

What is cushings Disease?

Answer 38

pituitary dependant adenoma

Question 39

What are ACTH dependant causes of Cushings?

Answer 39

ACTH dependent * Cushing’s disease (corticotroph adenoma) * Ectopic ACTH (lung cancer)

Question 40

What are ACTH indepedant causes of Cushings?

Answer 40

ACTH dependent * Taking steroids by mouth (common) * Adrenal adenoma or carcinoma

Question 41

What would you see in an investigation of Cushings?

Answer 41

1. Elevation of 24h free urine cortisol 2. Elevation of late night cortisol 12am 3. Failure to suppress cortisol after oral dexamethasone so increased cortisol secretion

Question 42

What do you do when hypercortisolism is confirmed?

Answer 42

Measure ACTH - if high then pituitary MRI, CTH dependant

Question 43

What are the main effects of non-functioning pituitary adenomas

Answer 43

visual disturbances - bitemporal hemianopia

Question 44

What are the hormonal affects of non-functioning pituitary adenomas?

Answer 44

Can present with hypopituitarism * Serum prolactin can be raised (dopamine can’t travel down pituitary stalk from hypothalamus)