Anterior Pituitary Flashcards
Dx acromegaly
elevate IGF-1
oral glucose tolerance test - normally glucose suppresses GH levels within 2 hours, glucose will no decrease below 1ng/ml in acromegaly
General causes of panhypopoituitaryism / hypopituitarism
Mass lesion
treatment of sellar, parasellar, hypothalamic diseases (surgy)
infiltrative disease (autoimmune, sarcoidosis, hemochromatosis
trauma
Vascular (Sheehans syndrome, pituitary tumor apoplexy
Medications
Infectious
Genetic
Developmental
Rx for Acromegaly
Octreotide+ Lanreotide (Somatostatin receptor ligands)
Cabergoline (DA agonist, limited effectiveness)
Pegvisomant (GH receptor blockade in liver)
normal potassium and no hyperpigmentation seen in ___ adrenal insufficiency
secondary
hormones of posterior pituitary
ADH
Oxytocin
DA agonists used for hyperprolactinemia, prolactin secreting adenomas, acromegaly, parkinsons
Bromocriptine
Cabergoline
clinical signs of GH def in neonate
in child
Neonate: jaundice
hypoglycemia
microphallus
traumatic delivery
Child: hypoglycemia
increased fat
high pitched voice
absent/late puberty
physical defects of skull, craniofacial abnls
GH receptor antagonist used for acromegaly
Pegvisomant
Testing procedures for ACTH
Cortisol 8am fasting
inuslin tolerance test (30, 60min) (insuf if cortisol repsonse
non-Rx treatment of Prolactinemas
Transsphenoidal ressection in patients not tolerating DA agonists
asymtpomatic require no treatment
Radiation for hihg surgical risk
Acromegaly etiology
typically GH-secreting pituitary tumor
Rx for GH def
side effects
recombinent humone growth hormones rGH
(SubQ nightly)
side effects: slipped femoral epiphysis
scoliosis
psuedotumor cerbri
snoring/sleep apnea from tonsil growth
somatostatin analogs used to treat acromgelly
Octreotide
lanreotide
contents of cavernous sinus
Internal carotids
CN III IV V1, V2, VI
(3+4+5.1+5.2+6)
clinical presentation ACTH deficiency (as in hypopituitarism)
weight loss
weakness, fatigue
nausea/vomiting/anorexia
abdl pain
arthralgias + myalgias
orthostatic hypotension
hyponatremia + glycemia
mechanism underlying decrease in male libido and decrease in menses in women seen in hyperprolactinemia
inhibition of pituitary gonadotropins FSH and LH
dx of hyperprolactinemia
serum prolactin above reference range
Endocrine/metabolic changes in Acromegaly
**menstrual abnls+male hypogonadism **- (PRL production by tumor or compression of gonadotrophs)
**galactorrhea - **PRL production or GH stimulation of PRL binding sites in breasts
**DM2 +impaired glucose tolerance - **anti-insulin effects of GH
hormones secreted from posterior pituitary originate in
paraventricular nuclei of hypothalamus
(transport via supraopticohypophyseal tract)
80% of IGF-1 circulates bound to
IGFBP-3
regulation of GH
GHRH and somatostatin (both from hypothalamus)
IGF-1 inhibits (negative feedback)
metabolic actions of GH
antagonizes insulin action
> increase lipolysis, Free FA porduction
increase protein synthesis
GH testing procedures
Basal IGF
GHRH arginine stimulation test
glucagon stimulation test
hormones of anterior pituitary
Prolactin
GH
ACTH
FSH
LH
TSH
clincila presentation of GH deficiency in adult
increased visceral fat, reduced lean body mass
reduced eneryg, social isolation, emotional lability+depression
reduced bone mineralization
elevated LDL and TG, low HDL
mild-moderate hyperprolactinemia most likely
infudibular stalk compression by a tumor, inhibition dopamine trasnport to lactotroph
systemic causes of hyperprolactinemia
neurogenic - chest trauma, surgery, herpes zoster
chronic renal failure due to decreased breakdown of PRL
Cirrhosis
Primayr hypothyroidism
Polycystic ovaran disease
physiological causes of hyperprolactinemia
pregnancy
lactation
exercice
sleep
stress
Rx hyperprolactinemia
DA agonists bromocrptine (esp in fertility induction)
cabergoline (preferred)
TSH or thyroid hormones is replaced with ___
ACTH or cortisol is replaced with ___
TSH or thyroid with levothyroxine or T4
ACTH or cortisol with hydrocortisone or prednisone
testing procedures for FSH LH
males - 8am fasting T (if below normal range or low with inappropriately normal LH+FSH)
females - basal serum estradiol
GH stimulates rlease of
IGF-1
clinical presentation of TSH deficiency or secondary hypothyroidism
weight gain
weakness, fatigue, lethary
cold intolerance
arthralgias+myalgias
Dry skin and hair
Constipation
diffuse edema, periorbital edema
bradycardia
drugs causing hyperprolactinemia
metoclopramide
risperidone
(both DA antagonists)
control of prolactin synthesis and secretion
tonic inhibition via Dopamine from hypothalamus
stimulation via thyrotropin releasing hormone
estrogen
vasopressin
VIP
oxytocin
EGF
(Thy Expression Varies Very Oddly, Ed
Acromegaly non-Rx treatment
must treat both the tumor an GH IGF-1 levels
- Transsphenodal surgery
- radiation therapy (10-15 years to see full effect)
- (Rx)
