Hypopituitarism Flashcards
Anterior pituitary hormones
Growth hormone
Prolactin
LH and FSH
Thyroid stimulating hormone
adrenocorticotrophic hormone
What’s the anterior pituitary blood supply called
Hypophyseal portal system
effects of each of the anterior pituitary hormones?
GH: growth, LH/FSH: testosterone/estrogen & progesterone, prolactin: milk production, ACTH: cortisol secretion, TSH: T3/T4 secretion
is a failure of the affected gland itself considered primary or secondary failure?
Considered primary
Pituitary failure is secondary
Hypothalamus is tertiary
Difference in TSH level between primary/secondary hypothyroidism
TSH is high in primary and low in secondary
name each of the pituitary hormone stimulators from the hypothalamus
GH: GHRH (growth hormone releasing hormone), FSH/LH: GnRH (gonadotropin releasing hormone), TSH: TRH (thyrotropin releasing hormone), prolactin: no direct one, ACTH: CRH (corticotropin releasing hormone)
How’s prolactin controlled
Inhibited by dopamine release
Congenital hypopituitarism
Rare cause by mutation of transcription factor genes needed for normal anterior pituitary development
Need to be deficient in GH and one other hormone
Panhypopituitarism
Total loss of anterior and posterior pituitary function
Examples of causes include pituitary tumour,trauma,radiation,infection
Inflammation (hypophysitis) or surgery.causes it
which hormones are most sensitive to radiotherapy?
GH and gonadotrophin
why is annual assessment required for pituitary radiation damage?
risks from radiotherapy persist for up to 10 years after dose
What’s sheehans syndrome
peripartum infarction of pituitary —> hypopituitarism
Caused by hypotension a common cause of which is postpartum haemorrage
Have lethargy weight loss TSH/ACTH/GH deficiency
Failure of lactation
Failure to resume menses
why does hypotension lead to pituitary infarction?
pituitary gland becomes enlarged during pregnancy (lactotroph hyperplasia)but the blood supply does not increase to compensate meaning it is at high risk of becoming hypoxic
Post partum haemorrage leads to pituitary infarction
why is the posterior pituitary not usually affected?
Separate blood supply not reliant on portal system
Best radiological way to visualize pituitary
MRI