functional pituitary adenomas Flashcards
(32 cards)
definition
adenoma of the pituitary gland which does secrete hormones
types of functional pituitary adenomas
- prolactin secreting adenoma (most common type) which causes hyperprolactinaemia
- growth hormone secreting adenoma which in children causes GIGANTISM and in adults causes ACROMEGALY
- adrenocorticotrophic releasing adenoma which causes CUSHINGS DISEASE
- thyroid stimulating hormone secreting adenoma (rare) causing secondary hyperthyroidism
- FSH and LH secreting adenomas (extremely rare) which cause reproductive dysfunction
hyperprolactinemia definition
hyperprolactinemia means increased prolactin levels in the blood
causes of hyperprolactinema subgroups
- physiological
- drugs
- pathological
physiological causes of hyperprolactinemia
breast feeding, pregnancy and stress
drugs that cause hyperprolactinemia
- anti-psychotics and anti-emetics as they are dopamine receptor antagonists
- anti-depressant which are selective serotonin reputake inhibitors
- cocaine
pathological causes of hyperprolactinemia
- prolactinoma
- damage to pituitary stalk
- hypothyroidism
symptoms of a prolactinoma are
different in men and woman and tend to present because prolactin inhibits the affects of FSH and LH on the ovaries and the testes
in females prolatinoma tends to be a
microadenoma
symptoms of proalctinoma in females
ammenorhoea
galactorrhea
in males prolactinoma tends to be a
macro adenoma
symptoms of prolactinoma in males
- bitemporal hemianopsia (no other cause of hyperprolactinamei except a prolactinma would cause this)
- gynaecomastia
- reduced libido and erectile dysfunction
investigations for prolactinoma
- prolactin levels
- MRI
MANAGEMENT OF PROLACTINOMA
DOPAMINE AGONIST (carbergoline)
what does carbergoline do
shrinks the tumour by around one third and also normalises prolactin levels in more than 95% of cases
acromegaly is nearly always caused by a
functional adenoma which secretes growth hormone
acromegaly can only occur in
adults (who’s growth plates are fused) if a growth hormone secreting pituitary adenoma occurs in children (who’s growth plates have not yet used) it causes GIGANTISM
features of acromegaly
- prognathism= protrusion of the lower jaw
- thickened soft tissues of the jaws, palms and fingers
- excessive sweating
- deepened husky voice
- hyper pigmentation
- teeth gapping
- gynaecomastia and galactorrhea
hands are feet in acromegaly are said to be
spade shaped
complications of acromegaly
- hypertension and cardiomegaly can cause congestive heart failure
- headaches caused by increased blood flow through the head due to the affects of growth hormone on the vasculature
- diabetes mellitus
- colonic polyps and colon adenocarcinoma
headaches in acromegaly are caused by
the increased blood flow through the head caused by the affect of growth hormone on the vasculature not because of the adenoma itself
diagnosis of acromegaly
- IGF-1 LEVELS
- glucose tolerance test: suppression test
glucose tolerance test
give 75g oral glucose
- in normal people growth hormone levels should all to less than 0.4 because increased blood glucose has a negative feedback affect of the hypothalamus and anterior pituitary
- in those with acromegaly growth hormone levels stay at 1 or above and may even rise this is because the negative feedback has nor affect because the tumour is producing growth hormone
if glucose tolerance test suggest acromegaly what should you do
get an MRI for definitive diagnosis
