hypopituitarism Flashcards
hormones secreted by anterior pituitary
growth hormone, prolactin, LH, FSH, TSH, ACTH
Hormone stimulated by growth hormone
somatotrophin
hormone stimulated by TSH
thyrotrophin
hormone stimulated by ACTH
corticotrophin
what happens to pituitary during pregnancy?
anterior pituitary (specifically lactotroph ) gets bigger (hyperplasia) and blood supply doesn’t grow accordingly (increased risk when trauma ect.)
how does hypothalamus communicate with anterior pituitary?
portal circulation
what is the only anterior pit hormone regulated negatively (inhibited) and by what hormone?
prolactin by dopamine
what is primary vs secondary gland failure?
gland fails: primary, pituitary or hypothalamus fails; secondary
give most common cause of primary and secondary gland failure
1: autoimmune (last year) , 2: tumour in pituitary or hypothalamus
what happens to TSH and t3 / t4 levels in primary hypothyroidism?
TSH goes up and t3/t4 goes down
what is TRH and where is it released from?
thyrotropin releasing hormone from hypothalamus
what happens to TSH and t3 / t4 levels in secondary hypothyroidism?
tsh goes down and t3 t4 also go down
which hormone(s) stimulates cortisol?
ACTH from pituitary gland
what happens to aldosterone levels in primary and secondary hypoadrenalism?
not affected because aldosterone is stimulated by renin-angiotensin NOT from pituitary gland
what is primary hypoadrenalism also known as?
adisons disease
most common cause of primary hypoadrenalism
autoimmune
what happens in primary hypoadrenalism
destruction of adrenal cortex
what happens to cortisol and ACTH levels in primary hypoadrenalism?
acth up and cortisol down
what happens to cortisol and ACTH levels in secondary hypoadrenalism?
both down
most common cause of secondary hypoadrenalism
pituitary tumour
common cause of primary hypogonadism in females
chemotherapy causing destruction of ovaries
common cause of primary hypogonadism in males
mumps
levels of LH, FSH, testosterone, oestrogen in secondary hypogonadism
all down
causes of hypopituitarism
congenital or acquired
is congenital or acquired hypopituitarism more common?
acquired
problem behind congenital hypopituitarism?
mutations of transcription factor genes needed for anterior pituitary development
what hormonal and growth deficiencies are seen in congenital hypopituitarism?
GH and at least 1 more anterior pit hormone and short stature
what is seen on MRI of hypopituitarism
hypoplastic (underdeveloped) anterior pituitary gland
does the term hypopituitarism more commonly refer to anterior dysfuncrtion, posterior or both?
usually anterior
in what cases does hypopituitarism also affect the posterior pituitary? (and so in these cases the term is used for that posterior dysfunction too)
inflammation (hypophysitis) or surgery
what is total loss of anterior and posterior pit function?
panhypopituitarism
WHAT ARE 8 causes of acquired hypopituitarism?
Tumours eg adenomas, metastases, cysts
Radiation (hypothalamic/pituitary damage)
Infection eg meningitis
Traumatic brain injury
Pituitary surgery
Inflammatory (hypophysitis)
Pituitary apoplexy - haemorrhage (or less commonly infarction)
Peri-partum infarction (Sheehan’s syndrome)
what parts of the HPA axis are sensitive to radiotherapy?
hypothalamus and pituitary
what pituitary cells and equivalent hormone are most sensitive to radiotherapy?
GH and gonadotrophin
what do doctors need to do when giving radiotherapy to ensure HPA axis health and why?
annual assessment for up to 10 years later bc radiotherapy kills DNA so rapidly growing cells die fast but slow growing cells: brain cells so pituitary cells may take up to 10 yrs
FSH LH related presentations of hypopituitarism in both genders
reduced pubic hair
reduced libido
FSH LH related presentations of hypopituitarism in females
secondary amenorrhoea
FSH LH related presentations of hypopituitarism in males
erectile dysfunction
ACTH related presentations of hypopituitarism
fatigue
(note) NOT a salt losing crisis (renin- angiotensin)
TSH related presentations of hypopituitarism
FATIGUE
GH related presentations of hypopituitarism
Reduced quality of life
NB short stature only in children
Prolactin related presentations of hypopituitarism
inability to breastfeed
some emphasised presentations in specifically Sheehans syndrome (post party hypopit)
anorexia, weight loss, lethargy (ACTH, TSH, (GH))
AMMENORHEA after delivery
not lactating
is posterior pit common involved in Sheehans?
no
What is the best radiological way to visualise the pituitary gland and why?
MRI: tumor and soft tissue, may reveal specific pit pathology (apoplexy, adenoma ect) (CT not so good at delineating pit gland)
what is an empty sella and how serious?
After tumour is gone pituitary is squished and theres empty space but they are COMPLETELY FINE ( if they can make the horm- you test for them) you just need to reassure them
what is pituitary apoplexy?
bleeding into the pituitary
who more commonly gets pituitary apoplexy?
people with pre existing pituitary adenomas (tumours) (might not be known)
what is a pituitary adenoma? (is it common is it serious?)
usually benign tumour, 1/5 people have one that doesn’t even matter and hasn’t been diagnosed
how can pituitary apoplexy be solved?
anti coagulants (blood thinners)
symptoms of pituitary apoplexy?
severe sudden onset headache
visual field defect (compressed optic chiasm, bitemporal hemianopia
cavernous sinus (vein thing remember?) involvement may lead to diplopia (IV, VI), ptosis (III)
what to consider when measuring cortisol in blood to diagnose hypopit?
time of day
what to consider when measuring T4 in blood to diagnose hypopit?
circulating t1/2 6 days
what to consider when measuring FSH/LH in blood to diagnose hypopit?
cyclical in women
what to consider when measuring GH/ ACTH in blood to diagnose hypopit?
pulsatle
what’s a better way to test for hypopit since pit hormones are pulsatile and dynamic?
1)cause a stress effect by inducing hypoglycaemia (<2.2mM).
2)this stimulates GH and ACTH release
3) acth stimulates cortisol which is the thing measured
Treatment of GH deficiency 2 non invasive
Assess Quality of Life (QoL) using
NICE guidance specific questionnaire
Treatment of GH deficiency 2 invasive
Confirm GH deficiency on dynamic pituitary function test
Daily injection (no oral option)
how to measure response to GH treatment
improvement in QoL
plasma IGF-1
what replacement is given in Treatment of TSH deficiency
levothyroxine
what Dif is there in treatment for TSH def as a result of hypopit compared to primary hypothyroidism?
1) you can’t measure TSH to adjust the dose of levothyroxine given
what t4 level should you aim for in replacement therapy? (since u can’t measure tsh u measure this)
above middle of reference range
what hormone is replaced in Treatment of ACTH deficiency
cortisol
what are the 2 replacement option drugs in Treatment of ACTH deficiency
Prednisolone once daily AM eg 3mg
Hydrocortisone three times per day eg 10mg/5mg/5mg
what is adrenal crisis?
patients with primary or secondary adrenal failure can get this when they are ill with smith (any common stuff)
adrenal crisis features
dizziness, hypotension, vomiting, weakness, collapse, even rarely death
what do adrenal failure patients (ppl taking steroid replacements) need to do when ill?
wear steroid bracelet
take double dose of their steroid
(go to A &E or inject themselves if they are vommiting and can’t take oral steroid)
why do they need this when ill?
body is in extra stress, they lack cortisol: stress responce hormone, they need to manage the stress
Treatment of FSH/LH deficiency - men
Replace testosterone – topical (put on skin and is absorbed) or intramuscular most popular
Treatment of FSH/LH deficiency - men check for efficiency
Measure plasma testosterone
can testosterone replacement help fertility?
no, Replacing testosterone does not restore sperm production
why Replacing testosterone does not restore sperm production
(this is dependent on FSH)
alternativeTreatment of FSH/LH deficiency - men for fertility ?
induction of spermatogenesis by gonadotropin injections
when best responce to gonadotropin injections in men?
if secondary hypogonadism has developed after puberty
gonadotropin injection check for efficiency
Measure testosterone and semen analysis
how long dies sperm prod take with gonadotropin injections and what does this mean for when u need to get it?
Sperm production may take 6-12 months ( need to do it around a year before kids)
Treatment of FSH/LH deficiency - women- no fertility - what is replaced and how?
oestrogen oral or topical
what extra is required for oestrogen replacement?
Will need additional progestogen if intact uterus to prevent endometrial hyperplasia (cancer)
Treatment of FSH/LH deficiency - women- fertility yes
Can induce ovulation by carefully timed gonadotropin injections (IVF)
Which anterior pituitary hormone axis does not need hormone replacement for everyone and why?
prolactin bc not everyone needs to breastfeed lol
