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Flashcards in Pituitary + Hypothalamus Deck (34)
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1
Q

How are the pituitary and hypothalamus connected?

A

Pituitary stalk/infundibulum

2
Q

What are the two parts of the pituitary gland and what do they produce?

A

Anterior = adeno (glandular):
GH, ACTH, TSH, FSH, LH, PRL
Posterior = neuro (neural):
ADH, OXT (oxytocin)

3
Q

What bone does the pituitary gland sit upon and what fossa is it within?

A

Sphenoid bone in sella turcica (Turkish saddle)

4
Q

What structures are contained within the cavernous sinus?

A

Carotid arteries,

CN III, IV, V1, V2, VI

5
Q

What paired hormones do the anterior pituitary hormones stimulate and where do they act upon?

A
TSH --> thyroxine (thyroid gland)
ACTH --> cortisol (adrenal gland)
GH --> liver/muscles
PRL --> direct action
FSH/LH --> reproductive glands
6
Q

What organs do the posterior pituitary hormones act upon?

A

ADH - kidneys

OXT - lactation stimulation

7
Q

Which hypothalamic hormones stimulate which pituitary hormones?

A
CRH --------- ACTH ------ cortisol
TRH ---------- TSH -------- thyroxine
GnRH -------- FSH/LH 
GHRH -------- GH
DA - - - - - - PRL (negative control)

ADH/OXT are stored in the posterior pituitary after production in the hypothalamus

8
Q

What test is used to measure cortisol production and how does it work?

A

Synacthen:
Give synthetic ACTH - looking for a rise in cortisol (indicates normal function of adrenals)
Check cortisol at 0,30,60 mins

9
Q

What test is sued to measure GH levels and what are you looking for?

A

Insulin stress test:

Looking for a rise in GH and cortisol when insulin given in starvation state (check every 30 ins for 2/3 hours)

10
Q

How is ADH production investigated?

A

Water deprivation test (over 8 hours), if urine concentration doesn’t increase = inadequate ADH production

11
Q

What causes diabetes insipidus?

A

ADH insufficiency

12
Q

How does diabetes insipidus present?

A

Polyuria, polydipsia, nocturia

13
Q

How is diabetes insipidus diagnosed?

A

Water deprived test, serum osmolality, U&Es

14
Q

What are the 2 types of diabetes insipidus and how are these differentiated on investigation?

A

Cranial (lack of ADH) or nephrogenic (unresponsive to existing ADH)
Vasopressin test:
after water deprivation give AVP and measure bodys response (if stop producing urine = cranial, if continue = nephrogenic)

15
Q

How are the two forms of diabetes insipidus treated?

A

Cranial: desmopressin
Nephrogenic: Thiazide diuretic + NSAID

16
Q

What is the main cause of SIADH?

A

Ectopic ADH production (from a paraneoplastic syndrome)

17
Q

How does SIADH present?

A

Very vague symptoms depending upon severity

Causes hyponatraemia and hypo-osmolality (due to excess water)

18
Q

How is SIADH investigated?

A

U&Es (hyponatraemia with hypoosmolality)
Urine dipstick (renal excretion of Na)
Concentrated urine

19
Q

How is SIADH treated?

A

Treat underlying cause (as often a tumour)

furosemide infusion with slow Na to replace losses

20
Q

Which side of the pituitary is panhypopituitarism most likely to affect and thus which hormones?

A
Anterior 
GH (growth failure/low mood)
TSH (hypothyroidism)
LH/FSH (hypogonadism)
ACTH (hypoadrenalism)
Prolactin (none)
21
Q

What are the causes of panhypotiuitrarism?

A

Most likely tumours (either primary or secondary)

22
Q

How does panhypopituitarism present?

A
Menstrual irregularities
Gynaecomastia
Abdominal obesity
Loss of facial hair (M)
Dry skin + hair
Hypothyroid facial features
23
Q

What is the main effect of low GH?

A

Low mood/depression

24
Q

How is panhypopituitarism investigated?

A
Check all hormone levels:
ACTH: cortisol - synacthen
TSH: thyroxine - fT4
LH/FSH: sex hormones - testosterone/estradiol
GH: IGF1
PRL: PRL
25
Q

How is panhypopituitarism treated?

A

Replace hormones:

thyroxine, hydrocortisone, ADH (desmospray), GH, sex steroids (testosterone/HRT)

26
Q

What is the difference between a micro and macro prolactinoma?

A

Micro <1cm

Macro >1cm

27
Q

How do men and women present with a prolactinoma?

A
Female:
EARLY presentation
menstrual irregularities/ammenorhoea
galactorrhoea
infertility
Male:
LATE presentation
impotence
visual field abnormality
headache
28
Q

How is a prolactinoma investigated?

A

Serum prolactin concentration
MRI pituitary
Visual field analysis (for bitemporal hemianopia)

29
Q

How is a prolactinoma treated?

A

Dopamine agonists (carbergoline)

30
Q

What is acromegaly?

A

Excess Growth hormone

31
Q

How is the main cause of acromegaly?

A

GH secreting pituitary tumour

32
Q

How is acromegaly screened for?

A

IGF1 (age and sex matched)

33
Q

What test is done to diagnose acromegaly and how does it work?

A

Glucose tolerance test (check GH 0,30,60,90,120 mins after glucose administration)
Glucose inhibits GH production; if remains normal or rises = acromegaly

34
Q

How is acromegaly treated?

A

Pituitary surgery or somatostatin analogues