Pituitary and Hypothalamus - Acromegaly, Kallman's, Pituitary adenoma, Prolactinoma, Pituitary apoplexy

Question 1

Acromegaly
-what is it
-presentation
-investigations
-management
-complications

Answer 1

Pituitary adenoma => too much GH

Coarse facial features
Spade hands
Increased shoe size
Excess sweating, oily skin
Hypopituitarism, headaches, bitemporal hemianopia

Gold standard - serum IGF
Confirm with OGTT
-no suppression of GH
-normally GH suppressed by high glucose

Pituitary MRI - pituitary tumour

1st line - Transphenoidal surgery
If not an option
-somatostatin analogue - octreotide

HTN
DM
Cardiomyopathy
Colorectal cancer

Question 2

Kallman’s syndrome
-what is it
-presentation
-investigations
-management

Answer 2

X recessive
-low FSH, LH => low sex steroids

Delayed puberty
Tall
Small, absent testes
ANOSMIA

Testosterone supplementation

Question 3

Pituitary adenoma
-what is it
-presentation
-investigations
-management

Answer 3

Benign pituitary tumour
-micro/macro - +-1cm
-functioning or non functioning

Non functioning => generalised hypopituitarism
Functioning => depends on the hormone affected
Bitemporal hemianopia
Headaches

Pituitary blood profile
Visual field testing
MRI brain contrast

Majority - transsphenoidal surgery
Medical - agonists or inhibitors of hormone being secreted in excess
RT - for residual or recurrent tumours after surgery

Question 4

Differentials for pituitary adenoma

Answer 4

Pituitary adenoma/hyperplasia
-COMES FROM BELOW OPTIC CHIASM

Craniopharyngioma - more common in children
-COMES FROM ABOVE OPTIC CHIASM

Brain mets

Question 5

Prolactinoma
-what is it
-presentation
-investigations
-management

Answer 5

PRL secreting adenoma

Men - impotence, low libido, galactorrhea
Women - amenorrhea, galatorrhea

Headache
Bitemporal hemianopia
Hypopituitarism

MRI brain

1st line - dopamine agonist
-cabergoline, bromocriptine
Transphenoidal surgery if medical not suitable

Question 6

Causes of galactorrhea

Answer 6

Pregnancy
Prolactinoma
Physiological - stress, sleep
PCOS
Primary hypothyroid
Phenothoazines, metocloPramide, domPeridone

Question 7

Pituitary apoplexy
-what is it
-risk factors
-investigations
-managemenet

Answer 7

Sudden enlargement of pituitary tumour

Risk
-HTN
-pregnancy
-trauma
-AC

Sudden SAH-like headache
Vomiting
Meningism
Bitemporal hemianopia - superior quadrant defect
Extraocular nerve palsy
Pituitary insufficiency
-low BP, Na from hypoadrenalism

MRI brain

IV HYDRO - priotitise
Careful fluid balance
Surgery

Question 8

Structure and function of hypothalamus and pituitary axis

Answer 8

Hypothalamus - SO, PV
-nuclei release releasing hormones into portal circulation => AP
Endocrine cells release trophic hormones into hypophyseal circulation => systemic circulation

Neural axons from hypothalamus release ADH, oxytocin directly into hypophyseal circulation in PP => systemic circulation

Pituitary in sella turcica in sphenoid
Pituitary next to optic chiasm

Question 9

Female hormone negative feedback system

Male hormone negative feedback system

Answer 9

Hypothalamus GnRH => AP gonadotrophs
FSH => follicle dev => O, inhibin
LH => ovulation => corpus luteum => P

FSH => Sertoli cells (spermatogenesis) => Inhibin
LH => Leydig cells => T
Leydig stimulate Sertoli

Question 10

GH
- function
- source
- regulation and release pattern

Answer 10

GHRH => somatotroph (most abundant cell in AP) => GH
Somatostatin => somatotroph => somatotropin => GH inhibition

Function

• growth of long bones until epiphyses fuse
• increase visceral size
• gluconeogenesis, lipolysis, protein synthesis
• cell growth
• stimulates IGF release from liver

Increases secretion

• pulsatile GHRH
• fasting (post prandial/drug induced hypoglycemia)
• exercise (tissue repair/AA infusion)
• sleep

Decreases secretion

• glucose
• somatostatin (increased by IGF)