What are primary, secondary, and tertiary disease? – ANSWER- Primary
- problem with the gland that secretes the hormone (ie: thyroid doesn’t
produce thyroid hormone)
Secondary – problem is the gland that controls the primary gland (ie.
pituitary doesn’t produce TSH to stimulate the thyroid)
Tertiary – problem with the gland that controls the secondary gland that
controls the primary gland (ie. hypothalamus not producing TRH ->no
TSH from pituitary -> no T3/T4 from thyroid)
How does the hypothalamus control the pituitary? – ANSWER- Controls
the anterior pituitary via hormones
Controls the posterior pituitary via neurohypophysis – direct nerve
stimulation
Posterior pituitary functions – ANSWER- Secrete ADH and oxytocin
ADH regulation – ANSWER- Anterior pituitary – osmoreceptors to
control ADH release and thirst
Increased release rapidly with elevated osmolarity
Also see increased release with nausea
ADH osmolar release set point is affected by:
Lower set point (release at lower osm) with pregnancy and pre-menses
Higher set point with chronic hypovolemia, acute HTN, corticosteroids
Anterior pituitary – hormones and controls (6 hormones) – ANSWER- 1.
ACTH – peak 3-4 am, nadir 10-11pm; stimulates corticosteroids and
androgens from adrenals; increase with corticotropin releasing hormone,
physical/psych stress
- Growth hormone – GHRH increases, somatastatin decreases, both
from hypothalamus - LH & FSH – produced by gonadotrophs; increased by pulsatile
secretion of GnRH from hypothalamus; Inhibin from ovary & testes
decreases FSH (only) production - PRL – tonic inhibition from hypothalamic dopamine; increase with
sleep, stress, lactation, nipple stimulation; Metaclopramine,
phenothiazines (decrease dopamine) increase PRL; Hypothyroid
modestly increases PRL - TSH – stim by TRH from hypothalamus, inhibited by T3, T4,
somatastatin
Pituitary adenoma cell types – ANSWER- 1. Lactotrophs – secrete PRL;
tied, most common macroademona - Gonadotrophs -tied, most common macroademona; presents as mass
effect +/- silent or panhypopit or gonadotropin hypersecretion - Somatotrophs- acromegaly
- Corticotrophs – cushings
- Thyrotrophs – hyperthyroidism (least common)
- Mixed (somatotrophs+lactotrophs) – acromegaly + hyperPRL
Mass effect sx of pituitary mass – ANSWER- HA, diplopia, visual field
defect, seizures; occasionally can get CNS rhinorrhea
Dx of pituitary adenoma – ANSWER- Sx first
Check MRI
Labs – PRL, IGF-1 (for acromegaly), 24 hr urine free cortisol or 1mg
overnight dexamethasone suppression test (for excess) or ACTH stim
test (for deficiency), TSH, FT4, alpha subunit of FSH, LH (confirms
pituitary origin)
If mass on MRI, but all labs normal, likely a non-pituitary tumor –
craniopharyngioma, meningioma, eosinophilic granuloma, histiocytosis
X, pituitary mets
Empty sella syndrome – ANSWER- Can be misread and be normal
multiparous women in 90% – pituitary compressed by CSF, but
functions normally
No treatment if no hormone abnormalities
Symptoms and labs in prolactinoma – ANSWER- Most common
functional tumors; usually microadenomas, can be space occupying
lesions
Elevated PRL->decreased release of GnRH->decreased LH/FSH->
decreased libido, ED in men, amennorhea and hirsutism in females;
Increased size=increased PRL, so if > 1cm and PRL<100, it’s not a prolactinoma 3 / 4 Men present later->only decreased libido, so present as space occupying
lesion (visual field defects)
Can cause galactorrhea in women, decreased bone mineralization
Causes of increased PRL – ANSWER- Prolactinoma, phenothiazines,
amitriptyline, metaclopramide (all decreased dopamine), estrogen
(inhibits dopamine->elevated PRL in pregnancy), hypothyroidism
Treatment for prolactinoma – ANSWER- Begin treatment when neuro sx
from size or sx of hypogonadism
Medical – dopamine agonists: Cabergoline and bromocriptine
Cabergoline -better tolerated, less nausea, 2x/wk dosing; increased valve
dz if high doses, contraindicated with valve dz, known lung dz,
retroperitoneal fibrosis
Surgery – is can’t tolerate meds; trtanssphenoidal; ofter rucurs
Radiation- to eradicate residual tumor post-surgery
Treating prolactinoma in pregnancy – ANSWER- Stop meds
Observe for sx, do visual field testing
1/3 enlarge in pregnancy – if enlarges enough to cause sx, restart
bromocriptine (safe in pregnancy)
Growth hormone regulation – ANSWER- Suppressed – hyperglycemia,
somatastatin, chronic steroids
Stimulated by – hypoglycemia, estrogens
Download full pdf here https://learnexams.com/search/study?query=