Hypopituitarism Flashcards
List the anterior pituitary hormones.
growth hormone (somatotrophin) prolactin ACTH (corticotrophin) FSH/LH TSH (thyrotrophin)
How do hypothalamic releasing/inhibitory factors travel to the anterior pituitary?
via portal circulation
What is the main difference between primary and secondary hypothyroidism?
primary = failure/loss of function of the thyroid gland secondary = failure of hypothalamus/anterior pituitary
Name a cause of primary thyroidism.
autoimmunity
Name a cause of secondary hypothyroidism.
pituitary tumour damaging thyrotrophs
Describe levels of TSH, T3 and T4 in primary hypothyroidism.
TSH high
T3/4 low
Describe levels of TSH, T3 and T4 in secondary hypothyroidism.
TSH can’t make it/falls
T3/4 low
Describe levels of ACTH and cortisol in primary hypoadrenalism.
ACTH increase
cortisol falls
Describe levels of ACTH and cortisol in secondary hypoadrenalism.
ACTH falls
cortisol falls
Describe levels of FSH/LH and testosterone/ oestrogen in primary hypogonadism.
FSH/LH high
testosterone/oestrogen low
Describe levels of FSH/LH and testosterone/ oestrogen in secondary hypogonadism.
FSH/LH low
testosterone/oestrogen low
What are congenital causes of hypopituitarism?
mutations of transcription factor genes needed for normal anterior pituitary development e.g. PROP 1 mutation
List acquired causes of hypopituitarism.
Tumours Radiation Infection Traumatic brain injury Pituitary surgery Inflammation Pituitary apoplexy Peripartum infarction
What is the term that describes the total loss of anterior and posterior pituitary function?
Panhypopituitarism
What affect does radiotherapy have on the pituitary?
Direct > acromegaly
Indirect > nasopharyngeal carcinoma
Which anterior pituitary cells are most sensitive to radiotherapy?
Gonadotrophs
List some presentations of hypopituitarism.
Reduced libido, erectile dysfunction, secondary amenorrhea
Fatigue
Reduced quality of life (short stature in children)
Inability to breastfeed
Explain the pathophysiology of Sheehan’s syndrome.
Hypotension in pregnancy / post partum haemorrhage > damage to pituitary > deficiency in pituitary hormones
Describe presentation of Sheehan’s syndrome.
Lethargy, anorexia, weight loss, failure of lactation, failure to resume menses post delivery
What is a pituitary apoplexy?
Intra pituitary haemorrhage or infarction
Pituitary apoplexy can be precipitated by?
Anti coagulants
Pituitary apoplexy presents as?
Severe sudden onset headache, visual field defect (compressed optic chiasm > bitemporal hemianopia), cavernous sinus involvement may lead to diplopia, ptosis
When using biochemical means to diagnose hypopituitarism you should take caution because?
Cortisol - what of time of day?
T4 - circulating time of 1/2 6 days
FSH/LH cyclical in women
GH/ACTH pulsatile
What would you see on a MRI of someone with hypopituitarism?
May be haemorrhage, adenoma, empty sella
Treatment of GH deficiency?
Daily injection of genotropin
Measure response by: improvement in QoL, plasma IGF-1
Treatment of TSH deficiency?
Replace with levythyroxine, (aim for a fT4 above the middle of the reference range)
Treatment of ACTH deficiency?
Replace cortisol
Synthetic glucocorticoids to mimic diurnal variation: prednisolone once daily AM, hydrocortisone 3x daily
Patients with ACTH deficiency are at risk of ‘………’ triggered by intercurrent illness.
Adrenal crisis
Features of adrenal crisis?
Dizziness Hypotension Vomiting Weakness Can result in collapse and death
What are sick day rules for those that take replacement steroid e.g. prednisolone, hydrocortisone?
Steroid alert pendant/bracelet
Double steroid dose if fever/intercurrent illness
Unable to take tablets, inject IM or come straight to A&E
Describe the treatment of FSH/LH deficiency in men (no fertility required).
Replace testosterone
Measure plasma testosterone
(This doesn’t restore sperm production)
Describe the treatment of FSH/LH deficiency in men (fertility required).
Induction of spermatogenesis by gonadotrophin injections (best response if develops after puberty)
Measure testosterone/semen analysis
Sperm production may take 6-12 months
Describe the treatment of FSH/LH deficiency in women (no fertility required).
Replace oestrogen
Additional progestogen if intact uterus to prevent endometrial hyperplasia
Describe the treatment of FSH/LH deficiency in women (fertility required).
Can induce ovulation by carefully timed gonadotrophin injections (IVF)
