ENDOCRINE - Pituitary conditions Flashcards
What is prolactin under tonic inhibition by?
Dopamine
What hormones are produced by the posterior pituitary?
ADH
Oxytocin
What is a pituitary adenoma?
Benign tumour of glandular tissue
Which syndrome are pituitary adenomas associated with
MEN I/IIa
Def microadenoma
<1cm
Def macroadenoma
> 1cm
What is the difference between functioning and non-functioning pituitary adenomas?
Functioning - secretory
PS: non-functioning pituitary adenoma (5)
Bitemporal hemianopia Ocular palsies Hypopituitarism Signs raised ICP e.g. headache Hypothalamic compression Sx
E.g.s of hypothalamic compression Sx (3)
Altered appetite
Thirst
Sleep/wake cycle
PS: functioning pituitary adenoma
Acromegaly
Hyperprolactinaemia
Cushings
Which hormones are rarely secreted from pituitary adenomas?
TSH
FSH
LH
PS hyperprolactinaemia (5)
Galactorrhoea Oligo/amenorrhoea Decreased libido Subfertility in M/ ereticle dysfunction Arrested puberty - younger pt
LT consequence hyperprolactinaemia
Osteoporosis
Causes hyperprolactinaemia
Prolactinoma
Breast stimulation/stress
Dx induced
Idiopathic
How is prolactinoma diagnosed?
Pituitary MRI
Following raised serum prolactin
Tx hyperprolactinaemia
DA agonists - ropinirole/bromocriptine
SE Ropinirole/bromocriptine (4)
N+V
Dizzy
Syncope
Fibrosis
What must be monitored on Ropinirole/bromocriptine
Echo due to fibrosis
XS GH in children –>
Gigantism
If prior to epiphyseal plate closure
XS GH in adults –>
Acromegaly
What is acromegaly almost always due to?
Pituitary tumour
Rarer causes acromegaly
Paraneoplastic - non- pituitary tumours
diagnosis acromegaly (2)
Raised IGF-1
GTT - normally suppresses GH secretion. Acromegaly - [ ] = 2mcg/ml at 2hrs
What does IGF-1 represent
GH levels over 24hrs
Sx acromegaly (9)
Change in appearance Increased hand/foot size Tired XS sweating Loss libido Sx DM Headaches Visual deterioration Sx hypopituitarism
Signs acromegaly (9)
Protruding mandible Prominent supraorbital ridge Interdental separation Large tongues Spade-llike hands/feet Tight rings VF defects HTN Hypopituitarism
Mx acromegaly
Somatostatin analogues to shrink tumour
Transphenoidal surgery
What is Cushing’s syndrome due to
Increased levels of glucocorticoid
Most common cause Cushings syndrome
Exogenous administration of steroids
Or XS endogenous secretions ACTH
ACTH dependent causes Cushings (2)
Cushings disease
Ectopic ACTH - non-pituitary ACTH secreting tumour
ACTH independent causes Cushings (2)
XS adrenal cortisol production - e.g. b.c adrenal tumour
Steroids
What is Cushings disease
Increased ACTH from the pituitary gland
Sx Cushings (= MOON FACE)
Menstrual changes Obesity (central) + striae Osteoporosis Neurosis/depression Facial plethora Altered mm (proximal myopathy) Calor skin Elevated BP (HTN)
What electrolyte disturbance may occur in Cushings (+ why)
Hypokalaemia
B/c of mineralcorticoid activity of cortisol
Diagnosis Cushings (3 tests)
1) Confirm raised cortisol w/ overnight dexamethasone suppression test
2) DDx ACTH indepedent + dependent causes - 9am + midnight plasma ACTH ((+ cortisol) levels
3) Which type of ACTH dependent is it? Low + high dose dexamethasone suppression test
Details of Overnight dexamethasone suppression test
Out pt
1mg PO dexamethasone given at night
Serum cortisol checked before + at 8am
Norm: -ve feedback –> cortisol levels decrease
Cushings: failure to suppress cortisol secretion
Details of 9am and midnight plasma ACTH (+cortisol) levels
If ACTH depressed/undetecable = adrenal cause likely
If ACTH is detectable = either pituitary or ectopic source