Pituitary Disorders Flashcards
size of microadenoma
<1cm-1cm
size of macroadenoma
> 1cm
physiological causes of raised prolactin
breast feeding
pregnancy
stress
sleep
pharmacological causes of raised prolactin
dopamine antagonists e..g metoclopramide phenothiazines TCA SSRIs oestrogens cocaine
pathological causes of raised prolactin
hypothyroid
stalk lesions
prolactinoma
how does hypothyroidism cause raised prolactin?
dopamine requires tyrosine- thyroxine is made from tyrosine and iodine
what is a prolactinoma?
adenoma of the pituitary gland that overproduces prolactin
presentation in females with prolactinoma
earlier presentation usually galactorrhoea menstrual irregularity infertility visual field abnormality headache
presentation in males with prolactinoma
impotence
visual field abnormality
headache
diagnosis of prolactinoma
high serum prolactin
MRI
visual fields e.g. bitemporal hemianopia
prolactin levels in macroadenoma?
20,000+
prolactin levels in microadenoma?
3,000+
management of prolactinoma
dopamine agonist e.g. cabergoline causes tumour shrinkage
adverse of cabergoline
nausea
vomiting
low mood
fibrosis of heart valves and retroperitoneum
what is acromegaly?
excess of GH
presentation of acromegaly
children gigantism (if before epiphyseal fusion) thickened soft tissues hypertension, early CV death headaches DM sleep apnoea, snoring carpal tunnel colonic polyps and colon cancer
thickened soft tissues examples in acromegaly
increased shoe size
spade hands
wedding ring too tight
diagnosis of acromegaly
measure IGF1
OGTT
visual fields
visualise the pituitary e.g. MRI
why do you measure IGF1 in acromegaly?
GH secretion is pulsatile
GH stimulates release of IGF1 from the liver
describe the OGTT in acromegaly
75g PO glucose and check GH every 30 minutes
normal= <0.4ug/l after glucose whereas in acromegaly it is unchanged/risen
management of acromegaly
transsphenoidal pituitary surgery radiotherapy somatostatin analogues dopamine agonists GH antagonists cancer surveillance, cardiovascular RF and sleep apnoea management
what can radiotherapy on the pituitary lead to?
hypopituitarism
somatostatin analogue use in acromegaly
sandostatin, octreotide and lareotide
relieve headaches and reduce tumour size
adverse if GI upset
dopamine agonist use in acromegaly
cabergoline and bromocriptine
better if co-secreting prolactin)
what is Cushing’s disease?
an excess of cortisol caused by pituitary adenoma secreting excess ACTH
what is Cushing’s syndrome?
signs/symptoms of excess cortisol caused by adrenal adenomas, ectopic or pseudo causes
ectopic production of ACTH
thymus
lung
pancreas
pseudo production of ACTH
alcohol
steroids
presentation of Cushing’s
myopathy, proximal wasting (proteolysis)
thin skin, striae, bruising
OP
hypertension, obesity, DM (stress hormone)
oedema (mineralocorticoids)
virilism, hirutism, oligo/amenorrhoea (androgen excess)
diagnosis of Cushing’s
screening= urine free cortisol and diurnal variation
low dose dexamethasone test
measure ACTH
management of Cushing’s disease
hypophysectomy (radiotherapy and bilateral adrenalectomy if recurs)
management of Cushing’s if unfit for surgery?
metyrapone
what is panhypopituitarism?
absence of pituitary hormones
causes of panhypopituitarism
pituitary tumours
surgery
granulomatous disease
presentation of panhypopituitarism
hypothyroid face abdominal obesity infertility, menstrual irregularity gynaecomastia loss of facial hair
diagnosis of panhypopituitarism
PFTs
can do suppression/stimulation tests
management of panhypopituitarism
hormone replacement
which hormone is abused in sport?
GH
why is cortisol replaced before levothyroxine in panhypopituitarism?
activates sympathetics and can cause adrenal crisis
adverse of testosterone therapy?
risks making cancers grow more
polycythaemia (stroke/MI)
hepatitis (LFTs)
cranial DI
problem with ADH in posterior pituitary
causes of cranial DI
familial (DIDMOAD)
acquired (tumour, trauma, idiopathic, inflammation)
diagnosis of cranial DI
water deprivation test/ desmopressin
water deprivation test result in cranial DI
osmol ratio >2 is negative
if low and improves after desmopressin, then cranial not nephrogenic
management of cranial DI
desmospray or desmopressin tablets/injections
