Pituitary Path Flashcards by Madelaine Hess

describe the physical findings of ICP

HA, NV
bradycardia
shallow breathing
HTN
papilledema

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bilateral temporal hemianopsia is due to

compression of the optic chiasm

result of mass effect

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how will pituitary apoplexy present?

s/o excruciating HA, diplopia and hypopituitarism

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what is the most common type of secretory pituitary adenoma?

prolactinoma/lactotroph

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describe the presentation of prolactinoma in females

galactorrhea and amenorrhea

also: decreased libido, mass effect (more in men), and infertility

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describe the presentation of prolactinoma in men

decreased libido, HA, and mass effect

also: decreased sperm count

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what has this histology?

stomal hyalinization with psammoma bodies
stains for PIT-1

prolactinoma

“pituitary stone” from the calcification

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describe the treatment for prolactinoma

dopamine agonists:
bromocriptine, cabergoline

surgery

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name other causes (5) of hyperprolactinemia in the absence of adenoma

pregnancy
lactation/nipple stimulation
loss of DA —> lactotroph hyperplasia
renal failure
hypothyroidism

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loss of DA can cause lactotroph hyperplasia, leading to hyperprolactinemia in the absence of adenoma

how can loss of DA occur?

damage to neurons via truama, stroke
drugs (verapamil; antipsychotics, antidepressants; metoclopramide)
mass

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renal failure can leading to hyperprolactinemia in the absence of adenoma

how?

producing excess prolactin yet excreting less because of the decreased clearance

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hypothyroidism can lead to hyperprolactinemia in the absence of adenoma

how?

increased TRH can stimulate PRL production due to a cross-reaction

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what is the LAM

lactational amenhorrhea method

if a woman is breast feeding, a state of elevated PRL, she will maintain anovulation

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how do you diagnose a somatotroph?

increased GH
increased IGF-1
oral glucose tolerance test (lack of GH suppression)

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describe the features of acromegaly in adults

jaw, spaid-like hands, feet
tongue
visceral organs (cardiac failure)

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secondary DM is present in somatotrophs

how?

GH induces liver gluconeogenesis

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GH induces somatomedin (IGF), describe the effects

increased linear growth of bone
increased organ size
decreased adiposity
increased lean body mass

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with respect to somatotrophs, five elements cause negative inhibition of the hypothalamus. what are they?

GHRH*
GH*
Glucose
FFA
somatomedin/IGF*

*negative feedback

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with respect to somatotrophs, what does the hypothalamus secrete to inhibit the pituitary gland and release of GH?

somatostatin

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in the world of somatotrophs

does somatomedin inhibit the hypothalamus or the pituitary gland?

IGF has negative feedback to both

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what is the treatment for somatotrophs?

somatostatin analog: octreotide
GH receptor antagonists
surgery

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40% of somatotrophs have what mutation?

GNAS

somatic mutation

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what does GNAS encode?

Gs-alpha

name the chromosome location of GNAS

20q13

what causes cushing disease?

corticotroph adenoma it will present with cushing syndrome because that is hypercortisolism and all of its baggage: central obesity, diabetes, vellous hirsutism, adrenal hyperplasia, violaceous striate, thin skin...the list goes on but only corticotroph adenoma can cause cushing disease

PAS+

corticotroph adenoma POMC is precursor to ACTH and B-endorphin

SF-1, GATA-2

gonadotrophs

paraneoplastic cushing syndrome name the three possible ectopic causes

1. small cell carcinoma of the lung 2. pancreatic carcinoma 3. neural tumor

elevated ACTH in the inferior petrosal sinus means the source is

pituitary

elevated plasma cortisol suppressed corticotropin level (no suppression on dexamethasone)

adrenal tumor or hyperplasia diagnose with CT; will have low ACTH after CRH stimulation test b/c ACTH-independent

elevated plasma cortisol elevated corticotropin level suppression on high-dose dexamethasone

corticotroph adenoma/cushing disease diagnose with MRI; elevated ACTH after CRH stimulation b/c ACTH-dependent

elevated plasma cortisol elevated corticotropin level no suppression on high-dose dexamethasone

ectopic source (small cell lung carcinoma, pancreatic carcinoma, neural tumor--all paraneoplastic) diagnose with MRI; elevated ACTH after CRH stimulation b/c ACTH-dependent

describe the treatment for corticotroph adenoma

- somatostatin analogs - bromocriptine - surgical excision (corticotroph adenomas express DA receptors and somatostatin receptors)

how will a patient with Nelson syndrome present?

hyperpigmentation as a result of greatly elevated ACTH (a-MSH stimulated by ACTH) - pre-existing corticotroph microadrenoma grows b/c no inhibition from adrenal corticosteroids

TPIT

corticotroph

USP8 mutation

corticotroph; results in EGFR upregulation *somatic mutation*

AIP

somatotroph *familial mutation*

well-circumscribed erodes bone bleed

adenoma

poorly circumscribed | invade brain

aggressive adenoma

where does pituitary carcinoma metastasize?

throughout the brain v. rare

rupture of what can result in inflammation of the pituitary or meningitis?

rathke's cleft cyst | ciliated columnar epithelium

10 yr old with growth retardation d/t hypopituitarism likely has

adamantinomatous craniopharyngioma WNT mutation ---> B-catenin

65 yr old with ICP or hypopituitarism, consider

papillary craniopharyngioma

solid, multiloculated/cystic mass impinging on optic chiasm describes

craniopharyngioma

cranipharyngiomas are derived from

rathke's pouch

histology showing: squamous epithelium wet keratin dystrophic, calcified cyst

craniopharyngioma

CSF leaking into the sella causes

primary sella syndrome -- compresses the pituitary usually an obese mxparous woman with vision changes

expansion of the pituitary resulting in infarct causes

secondary empty sella syndrome

postpartum woman presents with failure of lactation, loss of pubic hair, fatigue, and hypotension

sheehan syndrome -- necrosis of anterior pituitary

describe the pathogenesis of loss of pubic hair in sheehan syndrome

no LH from AP, so no androgens to produce pubic hair

is the anterior pituitary mostly dependent on arterial or venous supply?

venous

- increased serum osmolality, hypernatremia - dilute, excessive urine - polyuria

diabetes insipidus -- central or nephrogenic

if the kidney responds to DDAVP with increased water retention and increased urine sodium/osmolality, what kind of diabetes insipidus is it?

central DI

- mental status changes, seizures - muscle weakness - hyponatremia - hypernatriuria

SIADH

name the causes of SIADH

1. small cell carcinoma of the lung 2. TBI/SAH 3. SSRIs 4. pulmonary infection 5. COPD 6. cyclophosphamide

name two drugs that cause nephrogenic DI

lithium, demeclocycline