?

Log in

No account? Create an account

Previous Entry | Next Entry

Pituitary Pathology

What does pituitary mean, from the Latin? (think onomatopoeia...)
to spit mucus
ptuo = to spit, pituita = mucus

What do you call a hormone that acts on neighboring cells?
paracrine

Are pituitary hormones steroid, steroid type, or peptide hormones?
peptide, all of them are

What do you call the loss of lateral visual fields?
bitemporal hemianopsia

Damage to what part of the pituitary causes diabetes insipidus, and which hormone is lacking?
posterior pituitary, ADH

What kind of hormones are easily absorbed in the GI and through the skin?
steroids

How are peptides hormones administered?
injection

Why do they have to be injected?
because they are proteins they would be digested if swallowed
poorly absorbed by the skin
short half life

What are the main steroid-like hormones?
T3, T4, and vit D

What hormone is released from both the hypothalamus and the pancreas?
somatostatin
the brakes on the digestive system

What's another name for somatostatin?
GHIH
growth hormone inhibiting hormone

What's somatomedin?
growth hormone

What hormone inhibits prolactin?
dopamine

Is there CSF around the ant pit?
no, it's extradural

What membrane forms the lining of the anterior pituitary, and the diaphragma sella?
the dura mater
the dura can torque the gland

What embryonic structure is the anterior pituitary derived from?
Rathke's pouch

What is Rathke's pouch?
a depression in the roof of the developing mouth in front of the buccopharyngeal membrane
an invagination of the oral ectoderm
(the posterior pituitary originates from neuroectoderm)

Who was Rathke?
Martin Heinrich Rathke (1793-1860)
German embryologist and anatomist
professor of zoology and anatomy at Königsberg 1835-1860
studied marine organisms and the embryonic development of sex organs
first to describe gill slits and arches in the embryos of mammals and birds
1839 first described Rathke's pouch

What major arteries supply the hypophyseal arteries?
internal carotids

What connects the hypothalamus and the pituitary?
a portal system
the hypophyseal portal
portals = capillary bed to venule to capillary bed
also the nervous tissue which extends to the posterior lobe of the ant pit
(SSL's notes say the ant pit has the highest blood flow of any tissue and says that the hypophyseal arteries are branches of the internal carotids. He does not differentiate well between this perfusive flow and the portal flow which is local.)

What pituitary tumor is commonly found on autopsy but rarely diagnosed?
microadenoma
may cause amenorrhea, adrenal problems

What are the top five causes of hyperpituitarism?
adenoma
hyperplasia
non-pituitary tumors (SCC or small cell in lung making ACTH)
hypothalamic disorders
carcinoma (rare)

What hormone is usually produced by pituitary carcinoma?
prolactin

How much of the ant pit is usually gone before hypofunction is noted?
75%

What are some of the causes of hypopituitarism?
non-functioning tumor
surgery
radiation
ischemia
inflammation

What hormones are made by the ant pit?
According to SSL: FSH, LH, ACTH, TSH, prolactin, STH and MSH

What is STH?
somatotroph hormone aka growth hormone aka GH

So what hormones are made by the ant pit?
According to wikipedia:
One mnemonic used to remember the hormones produced by the anterior pituitary is: FLAT PEG (FSH, LH, ACTH, TSH, Prolactin, Endorphins and GH).
Another helpful mnemonic is that the hormones released by the basophiles are FLAT from BLUE cells, while the acidophiles are PEG from RED cells.

OK, without looking, list the hormones.

What is MSH?
melanocyte stimulating hormone
produced by intermediate lobe of ant pit
stimulate the production and release of melanin by melanocytes in skin & hair
MSH released into the brain has effects on appetite and sexual arousal
increases in humans during pregnancy + increased estrogens-->increased pigmentation in preg
Addison's disease: high adrenocorticotropic hormone (ACTH)-->high MSH levels-->darkening
red heads & those who don't tan well don't respond well to MSH in blood (receptors differ)

What are endorphins?
endogenous opioid polypeptide compounds
name implies "endogenous morphine"
produced by the pit and hypothalamus in vertebrates
during strenuous exercise, excitement, pain, death, and orgasm
resemble opiates: produce analgesia and a sense of well-being
"endorphin rush" in popular speech: exhilaration brought on by exercise, pain, danger
present immediately after injury
exogenous opioids-->inappropriate dopamine release-->aberrant synaptic plasticity-->addiction

What might you expect if a patient presents with bitemporal hemianopsia and papilledema?
expect an abnormal x-ray of the sella turcica (expansion, erosion, disruption) by a local mass

What hormones are most commonly overproduced by the ant pit?
GH and prolactin

What causes pituitary apoplexy?
hemorrhage

Which acidophilic cell types produces which hormones in the ant pit?
RED PEG
prolactin from lactotrophs
endorphins not sure where from SLL doesn't mention
and GH from somatotrophs

Which basophilic cell types produce which hormones in the ant pit?
BLUE FLAT
FSH from gonadotrophs
LH from gonadotrophs
ACTH from corticotrophs
TSH from thyrotrophs

What happens if the somatotrophs go haywire and overproduce?
gigantism if before bone maturity, acromegaly if after bone maturity
due to elevated GH

What other hormone may be elevated in folks with acromegaly?
prolactin

What proportion of somatotropic adenomas also produce prolactin?
1/3

What causes the joint pain in acromegaly?
thickened synovia

What causes the sleep apnea in acromegaly?
overgrown tongue, tracheal cartilage

What causes the low, rough voice ("hypothyroid voice")?
same cartilaginous overgrowth but in the vocal cords and surrounding ligaments/cartilage

Give ten signs or symptoms of acromegaly
heart: LV hypertrophy, arrhythmias, cardiomyopathy, CHF
increased glucose production, insulin resistance, impaired glucose tolerance
enlarged head, giant frontal sinus
prognathianism, large tongue
thickened synovium, tongue, tracheal cartilage, vocal cords, ligaments, cartilage
hyperostosis on anterior aspect of thoracic vertebrae
fatigue
big hands
thick heel pads

What happens to males who have too much prolactin?
gonadal atrophy<--decreased testosterone<--decreased LH
erectile dysfx
infertility, low libido

Why are menstruating women with prolactinomas diagnosed earlier than post-menopausal?
because they have amenorrhea, galactorrhea, infertility, low libido
both genders may also experience headaches and vision changes

If a woman has galactorrhea but is not pregnant or breastfeeding, what's the workup?
if serum prolactin is high, CT of the head

What's the treatment for prolactinoma?
dopamine agonists: bromocriptine
surgery (not a great option)
radiotherapy
replacement hormones

Where is the vomiting center of the brain?
in the 4th ventricle

Which cell types, basophilic or acidophilic, cause Cushing's disease?
BLUE FLAT // RED PEG
ACTH is blue so basophilic types

How common are thyrotroph adenomas?
very rare

What are the usual effects of gonadotroph adenomas?
mostly local effects, inefficient secretors

What are some of the causes of ant pit hypofunction?
displacement/impingement dt
1) non-secretory chromophobe adenoma (25%)
2) any mass lesion affecting the sella turcica
3) impingement of the stalk "stalk effect"
ischemic necrosis
1) pituitary aploplexy
2) Sheehan's syndrome

How will a woman know that she has Sheehan's syndrome?
she gives birth and the milk doesn't come, and her period never starts up again
and she gets really pale, is hypothyroid

What are some ways that the ant pit can get wedged over to one side (empty sella syndrome)?
a defect in the diaphragma sell allows the arachnoid and CSF to herniate into sella
a mass causes enlargement and then is removed, irradiated, or spontaneously necroses

What benign tumor originates from cells along the pituitary stalk?
craniopharyngioma
very slow growing
usually suprasellar
may be cystic

Who gets craniopharyngiomas?
children and men/women in their 50-60's
2/100,000

What other names are used for craniopharyngiomas?
Rathke pouch tumors, hypophyseal duct tumors, or adamantinomas

What inflammatory disease may affect the ant pit?
sarcoidosis

What syndrome can result from damage to the posterior pituitary?
diabetes insipidus!! (ADH deficiency)

What sorts of things can cause this damage?
suprasellar tumors, meningitis, abscess, TB
surgery or radiation
trauma
idiopathic

Which of the 3 P's is not present in diabetes insipidus?
polyphagia
(still have polyuria, polydypsia)

What hormone might you suspect is lacking when your patient presents with hair loss, voice changes, depression, fatigue, erectile dysfunction, muscle loss, and insulin resistance?
testosterone is lacking

Profile

moon
liveonearth
liveonearth

Latest Month

June 2019
S M T W T F S
      1
2345678
9101112131415
16171819202122
23242526272829
30      

Tags

Powered by LiveJournal.com
Designed by chasethestars