Pituitary Pathology - Martin- Hypo + rest Flashcards
what is hypopituitarism?
this is a decreased secretion of pituitary hormones due to disease of the hypothalamus or pituitary
hypofunction of the anterior pituitary occurs when _ percent of parencyhma is lost
75%
if there is posterior pituitary dysfunction _ can present and it is usually of hypothalamic origin
diabetes insipidus
what are most common causes of hypopituarism involving destruction of the anterior pituitary
- tumors/masses
- traumatic brain injury and subarachnoid hemmorhage
- surgery to the pituitary
- pituitary apoplexy
- ischemic necrosis of the pituitary/sheehan syndrome
- rathke cleft cyst
- empty sella syndrome
- hypothalamic lesions
- inflammatory lesions
- genetic defects
what is the presentation og pituitary apoplexy
abrupt onset of bad headache, diplopia, cardiovascular collapse, sudden death
ischemic necrosis of the pituitary aka sheehan syndtome aka post partum necrosis can cause hypopituitarism, how?
in pregnancy the anterior pituitary grows 2X its orignial size with no addition of blood supply, this gives a relative hypoxia and can lead to infarctionof the anterior pituitary
it can also be caused by DIC, sickle cell, increased intracranial pressure, traumatic brain injury
what is a rathnke cleft cyst in the pituitary? how does it cause hypopituitarism?
this is a cyst lined by ciliated cuboidal epithelium that can have fluid accumulation that can compress and compromise the normal pituitaty gland
what is empty sella syndrome
anything that destroys all or part of the pituitary
what is primary empty sella syndrome?
this is a defect in the diaphragma sella that allows arachnoid mater and csf to herniate into the sella expansing the sella and compressing the pituitary
primary empty sella syndrome is common in? and symptoms
obese women with multiple pregnancies
visual field defects, hyperprolactinemia, hypopituartism (if loos of functioning pituitary is sufficent)
what is secondary sella syndrome
a mass/adenoma that enlarges the sella and then it is removed or undergoes infarctio causing a loss of pituitary function
how can hypothalamic lesions cause hypopituitarism
there is a def in releasing factors from the hypothalamus to the pituitary which can cause dimimished released of ADH from the posterior pituitary and cause diabetes insipidus (this is just an example)
how can inflammatory disorders can hypopituitarism?
inlammatory disorders like sarcoidosis or tuberculosis can cause a def in anterior pit hormones or post pit hormones (diabetes insipidus)
what genetic defect can cause hypopituitarism?
PIT1 mutations which lead to deficiences in GH, prolactin and TSH
decreased gh leads to?
dwarfism and growth failure
decreases LH and FSH can cause
amenorrhea, infertilitym decreased libido, impotence, body hair loss
decreased TSH and ACTH cause?
hypothyroidism and hypoadrenalism
prolactin def causes
post partum lactation failure
melanotropin def causes
pallor
remmeber this is made from POMC precusor just like ACTH
_ is the term used to describe def in all pituitary hormones
_ hypopituitarism is more common. In general the secretion of _ is more likely to be affected
panhypopituitarism
GH/growth hormone
the signs and symptoms of anterior pituitary insufficeince may occur _ (fast/slow/both)
slowly or suddenly (both)
central diabetes inspiidus is?
a def of ADH from the posterior pituitary
genetic cause of central diabetes insipidus
other causes of central diabetes insipidus
symptoms
AVP AD mutation
AVPR2 X linked mutation
head trauma, tumors, inflammatory disorders of the hypothalamus
polyuria *** increased serum sodium and osmolality—> dehdraytion—–> polydipsia
large volumes of dilute urine (less salty, salt is staying in the blood)
usually dehydration can be combated with increased water intake
what is syndrome of inappropriate ADH (SIADH)
increased ADH leads to over resportion of free water and this leads to hyponatremia (low salt in the blood because water is diluting it)
what causes SIADH
ectopic ADH from small cell carcinomas of the lungs, drugs , infections, trauma
symptoms of SIADH
hyponatremia, cerebral edema, neurologic dysfunction, increased TBW, normal blood volume
no peripheral edema
if you adminster DDVAP in central diabetes insipidus what happens
the kidney will respond with increased water retention and increase urine sodium/osmolality
urine output in DI vs . SIADH
serum NA in DI vs SIADH
Urine Na in Di vs SIADH
Serum OSM in DI vs SIADH
Urine OSM in DI vs SIADH
Volume status in DI ws SIADH
urine output in DI vs . SIADH- high for DI
serum NA in DI vs SIADH- High for DI
Urine Na in Di vs SIADH- low for DI
Serum OSM in DI vs SIADH- high for DI
Urine OSM in DI vs SIADH- low for DI
Volume status in DI ws SIADH- low for DI
DI and SIADH are opposite values
SIADH direct effect on ADH on the brain results in inapproporiate. _
thirst
hypothalamic suprasellar tumors can cause _ or _ in the anterior pituitary or posterior pituitary or a combination of both
hypofunction or hyperfunction
what are the types of hypothalamic suprasellar tumors?
glioma and craniopharyngioma
what is a craniophryngioma?
a vestigial remnant of rathke pouch that is a slow growing intracranial tumors with a bimodal peak at ages 5-15 and over 65 years old
symptoms of craniopharyngioma
headache, visual disturbances, groth restriction in kids
apperacne of a craniopharyngioma
3-4 cm, solid or cystic, or multioculated, encapsulated
craniopharyngiomas can enroach on the _ and bulge into the _ and _ of the brain
optic chiasm
floor of the 3rd venrticle
and base of the brain
what are the two types of craniopharyngiomas?
adamantinomatous and papillary
an adamantinomatous craniopharyngioma is most often seen in _ and _ are seen on radiographs. There is a mutation in _
kids
calcifications
CTNNB1 (b carenin)–> activation of the Wnt signaling pathway
how does an adamanitnomatous craniopharyngioma look
nets and cords of stratified epithelium embedded in a spongy reticulum
palisading of equamous epithelium
compact wet keratin
calcifications
machine oil cholesteral rich deposits
fingerlets into the epithelium adjacent to the brain giving a brisk flial rxn
cholesterol crystals
malignant transformation of craniopharygiomas into squamous carcinomas is rare but usually occurs after _
radiation
papillary craniophayngiomas are seen in _ and have solid sheets and _ lined by squamous epithelium. They lack _, _, _, and _.
there is a _ mutation
adults
lack lamella keratin, calclifications, cysts, peripheral palisading
BRAF mutations at codon 600
