Pituitary Pathology Flashcards
Where does most pituitary pathologies occur - anterior or posterior?
anterior
What is the mnemonic to help remember what hormones are secreted by the basophils of the atnerior pituitary?
B-FLAT
Basophils secrete FSH, LH, ACTH and TSH
So what two hormones come from the acidophils?
growth hormone and prolactin
What two hormones are released by the posterior pituitary? Where are they made though?
oxytocin and ADH (vasopressin)
made in the hypothalamus
What are the things oxytocin is associated with?
labor
milk let-down
cuddling (after orgasm)
monogamy (in vole studies)
trust (investment experiment)
Hyperpituitarism causes too much hormone from the ____ pituitary
anterior pituitary
What are the 5 potential causes of hyperpituitarism?
pituitary adenoma (BY FAR the most common)
destruction of end organs (loss of negative feedback)
hypothalamic disorders (rare)
hyperplasia of atnerior lobe (rare)
carcinoma of anterior lobe (rare)
True or false: it takes a while for symptoms to show for pituitary adenomas
true
Why can pituitary adenomas cause visual deficits?
mass effect (especially the non-functional big ones) - bitemporal hemianopsia
can also cause increased intracranial pressure and HYPOpituitarism (if a big non-functional squishes the rest of the functional pituitary)
How big must a pituitary adenoma become in order to be considered a macroadenoma?
1 cm
True or false: pituitary adenomas are usually invasive
false
but some can grow aggressively fast and grow out of the sella - NOT malignant though
What tumor syndrome can pituitary adenomas be associated with?
MEN 1
What is the microscopic appearance of a pituitary adenoma?
- sheets/cords
- uniform cells of one type
- may be pleomorphic
- may have mitoses
True or false: you can usually tell the hormonal type of pituitary adenoma based on microscopic appearance.
false
What is the most common hormone to be produced by a pituitary adenoma?
prolactin
What is the least likely hormone to be produced by a pituitary adenoma?
TSH
What are the 4 general classes of genes that can be mutated in pituitary adenoma?
- mutated GNAS1 gene
- mutated MEN-1 gene
- Mutated RAS
- Mutated c-MYC
What is the term for the most common type of pituitary adenoma?
Prolactinoma
What are the symptoms of a prolactinoma?
amenorrhea
galactorrhea
How do we treat prolactinomas?
dopamine receptor agonists
What will occur in a pre-pubertal growth hormone adenoma?
gigantism
What will occur in a post-pubertal growth hormone adenoma?
acromegaly
What are some additional manifestations of growth hormone adenomas?
diabetes mellitus
hypertension
arthritis
gastrointestinal carcinoma
What would be the laboratory findings in a GH adenoma?
- increased GH (that comes in spurts)
- increased IGF-1 (makes a better marker)
- GH will be unresponsive to glucose (it should go up)
What are the three diseases/syndromes that occur with an ACTH adenoma?
Cushing syndrome (high cortistol in blood) Cushing disease (from pituitary adenoma) Nelson syndrome (if you take out the adrenals by mistake, the adenoma loses the cortisol inhbition and it grows huge)
What happens in a pituitary cushing syndrome?
the anterior pituitary makes too much ACTH, leading to too much cortisol, leading to cushings
What happens in an adrenal cushing syndrome?
there’s normal ACTH, but the adrenal gland either has a tumor secreting cortisol or nodular hyperplasia secreting cortisol
Cancer of what organ will most often cause a paraneoplastic cushing syndrome?
lung cancer - the tumor secretes ACTH, which promotes adrenal hyperplasia and increased cortisol
What happens to the adrenal gland when there is iatrogenic cushing syndrome from long-term steroid use?
adrenal atrophy
What do FSH/LH adenomas and non-functioning adenomas have in common?
they can get really big
because they present late without the endocrine symptoms
What are the 5 general causes of hypopituitarism?
1 pituitary destruction
- ischemic necrosis
- empty sella syndrome
- pituitary apoplexy
- hypothalamic lesions
What are two ways the pituitary can be destroyed?
- by a big pituitary adenoma
2. by surgery or radiation
What are the two reasons that the pituitary can undergo ischemic necrosis?
- For whatever reason, the pituitary gets BIG, but blood flow remains the same (USUALLY PREGNANCY)
- Hemorrhage elseqhere causes hypotension and decrease in perfusion
result: the pituitary (which is already hypoxic) becomes necrotic
Describe what happens in empty sella syndrome.
you can get arachnoid or CSF herniation into the space leading to pituitary compression and what looks like an empty sella on MRI
True or false:empty sella syndrome is usually associated with hypopituitarism.
false
usually still have enough pituitary to make enough hormone to be asymptomatic
What causes pituitary apoplexy?
sudden infarction of an adenoma
remember they can bleed quite suddenly
What type of symptoms will pituitary apoplexy present with?
meningeal symptoms
True or false: the clinical onset of hypopituitarism is usually insidious and chronic.
true
How many hormones are usually affected by hypopituitarism?
one or two
panhypopituitarism is rare
What is the order of hormones affected by hypopituitarismfrom most common (first) to least common (last)?
GH
FSH/LH
TSH
ACTH
What happens with too little GH?
pituitary dwarfism
muscle weakness
What happens with too little FSH/LH?
loss of libido
menstrual abnormalities
What happens with too little prolactin?
inability to lactate
What happens with too little TSH?
hypothyroidism
What happens with too little ACTH
adrenal insufficiency
What are the two posterior pituitary syndromes?
- diabetes insipidus
2. Syndrome of Inaporporpiate ADH secretion
What happens in diabetes insipidus?
decreased ADH
pee dilute urine
serum osmolality incresaes
increase water intake
What happens in syndrome of inappropriate ADH secretion?
increased ADH
retain water
blood becomes hypotonic
decreased water intake
What type of cancer can cause SIADH?
small cell lung CA with ectopic ADH production