Pituitary Flashcards
what hormones are in excess in cushings?
cortisol, mineralocorticoid and androgen
what are the characteristics of Cushings?
thin skin, proximal myopathy, frontal balding, conjunctival oedema, osteoporosis
what is the definitive test for Cushings?
Dexamethasone suppression test
what results of the Dexamethasone suppression test indicate Cushings
Cortisol of greater than 50nmol/16 hours after the last dose
what are the screening tests for Cushings?
overnight dexamethasone test, urine free cortisol test and diurnal cortisol variation
what test results would indicate Cushings was caused by the pituitary?
Low dose Dexa test = Abnormal
ACTH = (below 300)
High dose Dexa = suppressed by 50%
what test results would indicate Cushings was caused by adrenals?
abnormal low dose Dexa,
ACTH less than 1
what test results would indicate Cushings had an Ectopic cause?
abnormal low Dexa,
ACTH higher than 300
what are the causes of hypopituitarism?
pituitary tumours, secondary metastases, brain tumours, granulomatous disease, trauma
how do we diagnosis diabetes insipidus?
water deprivation test
what is the affect of pressure on the optic chiasm?
bitemporal hemianopia
what drugs can raise prolactin?
dopamine antags, anti depressants/psychotics
pathological causes of raised prolactin
hypothyroid, stalk lesions, prolactinoma
what is the treatment of prolactinoma?
dopamine agonists
what is acromegaly?
GH excess
what is the adenohypophysis?
anterior pituitary
what is the anterior pituitary derived from?
Rathkes pouch
the anterior pituitary secretes trophic (4) and non trophic (2) hormones, name them
trophic: TSH, ACTH, FSH, LH
nontrophic: GH and prolactin
what is the neurohypophysis
posterior pituitary
what is the posterior pituitary an extension of
neural tissue, glial cells and axonal processes
what does the posterior pituitary secrete?
ADH and oxytocin
what can cause hyper function of the anterior pituitary?
adenoma, carcinoma
what can cause hypo function of the anterior pituitary?
surgery, haemorrhage, necrosis, tumours extending into sella, inflammatory conditions
what is diabetes insipidus
lack of ADH
what is the most common cause of function pituitary adenoma?
prolactinoma
what is the second most common cause of functional pituitary adenoma?
Growth hormone secreting
what is nephrogenic Diabetes Insipidus?
renal resistance to ADH
what is a craniopharyngioma derived from?
remnants of rathkes pouch
what does igf mean
insulin growth factor
if the results of igf are high, what does this indicate?
chronic disease
what cranial nerve controls lateral movement of the eye?
abducent
