Hypopituitarism & Anterior Pituitary dysfunction Flashcards
what are the anterior pituitary hormones
Growth Hormone Prolactin Thyroid stimulating hormone Lutenising hormone/Follicle stimulating hormone Adrenocorticotrophic hormone
where does the pituitary sit
sella turcica of sphenoid bone
what does the anterior pituitary rely on?
the hypothalamus (to regulate function by releasing or inhibiting factors)
what factors are released by the hypothalamus for the AP
growth hormone releasing hormone somatostatin thyrotrophin releasing hormone dopamine gonadotrophin releasing hormone corticotrophin releasing hormone
what is a primary endocrine disease
disease where the pathology originates in the gland itself e.g ovaries
what is a secondary endocrine disease
disease where the pathology originates in the signals from the hypothalamus/anterior pituitary
what is primary hypothyroidism
thyroid doesn’t produce thyroxine
Hashimotos
T3&4 fall TSH high
what is secondary hypothyroidism
thyroid functioning, no releasing signals
TSH falls, T3/4 fall
what is primary hypoadrenalism
Addisons disease
adrenal cortex damaged/destroyed by autoimmune
ACTH high, cortisol low
what is secondary hypoadrenalism
adrenal cortex functioning,
but can’t make ACTH
ACTH falls, cortisol low
what is primary hypogonadism
gonads not functional
LH and FSH high, test/oest low
what is secondary hypogonadism
gonadotrophs (pituitary) damaged/hypothalamus damage
LH/FSH fall, test/oest fall
congenital causes of hypopituitarism
mutations for anterior pituitary transcription e.g PROP1
what are the signs of congenital hypopituitarism
deficient in GH & at least one more hormone since birth
hypoplastic (underdeveloped) anterior pituitary
acquired causes of hypopituitarism
Tumours radiation infection traumatic brain injury pituitary surgery inflammation/autoimmunity pituitary apoplexy
what is hypophysitis
inflammation of the pituitary or infundibulum
what is pituitary apoplexy
bleeding into a pituitary adenoma (causing sudden enlargement and damaging the pituitary)
what is the name for complete loss of pituitary function (post. and ant.)
panhypopituitarism
what are the causes of pituitary apoplexy
haemorrhage
less commonly infarction
what procedures may cause radiotherapy-induced hypopituitarism
acromegaly treatment (radio right to pit.) nasopharyngeal carcinoma treatment (indirect)
what hormones are most sensitive to radioactivity
Growth hormone and gonadotrophins
Prolactin
how long does the risk of radiotherapy persist for?
up to 10yrs
requires annual assessment
how does hypopituitarism affecting LH/FSH present?
reduced libido
secondary amenorrhoea
erectile dysfunction
reduced pubic hair
how does hypopituitarism affecting ACTH present?
fatigue
no salt balance issues
how does hypopituitarism affecting TSH present?
fatigue, weight gain
how does hypopituitarism affecting GH present?
reduced quality of life, short stature in children
how does hypopituitarism affecting Prolactin present?
inability to breastfeed
what is sheehan’s syndrome?
post-partum hypopituitarism secondary to hypotension/post-partum haemorrhage
how does sheehans syndrome happen?
anterior pituitary damaged following hypotension during delivery, causing pituitary infarction
what are the signs of sheehans syndrome
lethargy, anorexia, weight loss, failure of lactation, failure to resume menses
what happens to the pituitary during pregnancy
enlargement (lactotroph hyperplasia)
what is the onset of pituitary apoplexy?
dramatic and sudden
often precipitated by anti-coagulants
what are the signs of pituitary apoplexy
severe sudden onset headache
visual field defect - bitemporal hemianopia
possible diplopia and ptosis
what methods can be used to diagnose hypopituitarism
blood tests, dynamic pituitary function tests (stress test), pituitary MRI
what hormone dysfunction cannot be treated
prolactin
what is the guidance for treating hypopituitarism affecting GH?
daily injection of GH
measure response by improvement in quality of life and plasma IGF-1
how to confirm GH treatment is working
assess quality of life and measure response to this
measure plasma IGF-1
what is the guidance for treating hypopituitarism affecting TSH
once daily levothyroxine
aim for fT4 above middle of reference range
what is the guidance for treating hypopituitarism affecting ACTH?
prednisolone once daily AM
or
hydrocortisone 3x daily
what is an adrenal crisis
dizziness, hypotension, vomiting, weakness triggered by intercurrent illness
can collapse and die
what should patients taking replacement steroids be advised to do?
keep steroid alert pendant
double steroid dose if fever/intercurrent illness
if unable to take tablets, inject IM or come to A&E
what are the guidelines for hypopituitarism affecting LH/FSH in men?
replace testosterone topically or IM
if fertility required - gonadotrophin injections, sperm production should resume 6-12 months after
when is fertility in men best conserved?
if secondary hypogonadism developed after puberty (gonads are right size/development)
what are the guidelines for hypopituitarism affecting LH/FSH in women?
oral or topical oestrogen
addition of progesterone if uterus is intact to prevent endometrial hyperplasia
if fertility is required, carefully timed IVF and gonadotrophin injections can induce ovulation
signs/presentation of pituitary apoplexy
sudden onset - blood/haemorrhage in cavernous sinus
cranial III defect as blood compresses this - ptosis
