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)
