Endocrine part 1 outside source

"Coordinating center" at the base of the brain that consolidates info and delivers precise signals to pituitary gland

hypothalamus

releases hormones to endocrine systems in response to hypothalamus

pituitary gland

releases GH, prolactin, ACTH, TSH, LH, and FSH

anterior pituitary

stores and releases oxytocin and arginine vasopressin

posterior pituitary

1 multiple choice option

stimulates breast milk production after childbirth

prolactin

stimulates growth in childhood and maintains muscle and bone in adults

targets the skeletal system

growth hormone

stimmies the production of cortisol

targets the adrenal cortex on the kidneys

ACTH

stress hormone that controls BP and sugar under stressful conditions

cortisol

regulates metabolism, energy balance, growth, and nervous system

targets thyroid gland

TSH

stimmies testosterone production in men and ovulation in women

targets the testes and ovaries

LH

promotes sperm production in men and egg/estrogen production in women

targets the testes and ovaries

FSH

regulates water balance in the body and sodium levels in the blood

targets the kidneys

ADH or vasopressin

stimmies milk flow during breastfeeding, promotes labor during childbirth, and bonding btwn mother and child

targets breasts and uterus

oxytocin

which hypothalamic inhibitory hormone inhibits the release of GH?

somatostatin

decreased or absent secretion of one or more pituitary hormones

hypopituitarism

what does the presentation of hypopituitarism depend on?

- which hormones involved (one, several, or all)

- extent/acuity of the hypofunction

- age of presentation

TSH deficiency presents as

central hypothyroidism aka cold intolerance, constipation, dry skin

ACTH deficiency presents as

hypotension, fatigue, weight loss

PRL deficiency presents as

inability to lactate after delivery

FSH/LH deficiency presents as

lack of puberty, decreased estrogen, decreased testosterone, loss of axillary/pubic hair

GH deficiency presents as

obesity, reduced muscle mass or bone density, decreased energy/concentration

AVP/ADH deficiency presents as

central diabetes insipidus aka polyuria, excretion of large volume of dilute urine

oxytocin deficiency presents as

slow labor/decreased contractions and poor letdown of breastmilk

hypopituitarism due to mass lesion/inflammation will cause

- HA

- visual field deficits

- dizziness

- confusion

hypopituitarism due to damage of hypothalamus will cause

- obesity

- cognitive impairment

- HA

- visual field deficits

what lab do you order if concern for ACTH deficiency?

serum cortisol

what lab(s) do you order if concern for FSH/LH deficiency?

- serum total testosterone

- serum estradiol

- check PRL

what lab(s) do you order if concern for GH deficiency?

difficult to test, potentially IGF-1

what lab(s) do you order if concern for TSH deficiency?

- TSH

- free T4

when would ordering a BMP be appropriate?

- hypoadrenalism

- hypothyroidism

- GH deficiency

when is an MRI indicated for hypopituitarism? when is it NOT indicated?

if a mass lesion is suspected; functional hypopituitarism

what is the treatment of ACTH deficiency?

hydrocortisone PO

what is the treatment of PRL deficiency?

no current available treatment

what is the treatment of TSH deficiency?

first confirm no adrenal insufficiency present, then levothyroxine

what is the treatment of gonadotropin deficiency in males not seeking fertility?

testosterone

what is the treatment of gonadotropin deficiency in males seeking fertility?

hCG IM

what is the treatment of gonadotropin deficiency in females seeking fertility?

trial clomiphene and ovulation induction with FSH/hCG

what is the treatment of gonadotropin deficiency in premenopausal females not seeking fertility?

estradiol-progestin

what is the treatment of adult onset GH deficiency?

RhGH injection available if not critically ill; but treatment usually not recommended

when is transsphenoidal surgery recommended for hypopituitarism?

pituitary masses and cysts

functional hypopituitarism can reverse if _____

exercise is reduced and patients gain appropriate weight

what are the congenital causes of pediatric GH deficiency?

genetic disorders like prader-willi syndrome

what are the acquired causes of pediatric GH deficiency?

intracranial tumors, radiation, head trauma

what is the clinical presentation of congenital pediatric GH deficiency?

- reduced birth length

- deviation from normal growth curve

- hypoglycemia if combined with ACTH deficiency

- microphallus and cryptorchidism if combined with gonadotropin deficiency

what is the clinical presentation of acquired pediatric GH deficiency?

- severe growth failure, delayed bone age

- increased weight/height ratio

what are the labs/imaging for pediatric GH deficiency?

- reduced IGF-1

- delayed bone age (hand/wrist xray)

- GH stim test (limited)

- MRI for tumor eval

what is the treatment for pediatric GH deficiency? how long do you treat?

RhGH SQ if epiphyses are still open; treat until full skeletal maturation

uncommon disease related to vasopressin (ADH) deficiency

central diabetes insipidus (aka AVP-D)

low secretion of ADH in central diabetes insipidus will reduce _____ and lead to low blood volume and increased ____

water retention; dilute urine

what is AVP-D is most commonly caused by?

- idiopathic

- surgery/TBI

- primary tumor or metastasis

- infiltrative dz

what can exacerbate AVP-D?

pregnancy

how will AVP-D clinically present?

- polyuria

- polydipsia

- neurologic sx

- nocturia/enuresis

- dehydration

what are the labs/imaging for AVP-D?

- 24 hr urine

- low specific gravity on urinalysis

- < 300 urine osmolality

- high to normal serum sodium

- vasopressin challenge test

- MRI

how is the vasopressin challenge test administered?

- desmopressin acetate intranasally

- measure urine volume 12 hr before and after

what is indicative of AVP-D with the vasopressin challenge test?

clear reduction in polyuria/polydipsia

what is found on MRI in AVP-D?

bright spot of a healthy posterior pituitary is undetectable or small

what are possible ddx of AVP-D?

- AVP-R

- DM

- primary/psychogenic polydipsia

- cushing

- hypercalcemia/hypokalemia

what is the treatment of AVP-D?

- desmopressin acetate at bedtime to help alleviate nocturia

- if mild dz, adequate fluid intake

rare disorder involving impaired water excretion caused by inability to suppress ADH secretion

SIADH

what are the most common causes of SIADH?

- CNS disorders (stroke, hemorrhage, infx, etc)

- ectopic production of ADH (small cell lung cancer)

- drugs (SSRI's, carbamazepine, MTX, NSAIDS, PPI)

- pulmonary dz (PNA, resp failure, pneumothorax)

water retention in SIADH leads to ______ and ______

hyponatremia and concentrated urine

what is the treatment of SIADH?

- fluid restriction

- salt administration

- vasopressin receptor AA

- diuretics

excessive GH secretion that begins prior to puberty/closure of epiphyses

gigantism

1 multiple choice option

excessive GH secretion that occurs AFTER puberty gradually

acromegaly

1 multiple choice option

gigantism and acromegaly is almost always caused by a ______

GH-secreting pituitary adenoma

what is the clinical presentation of gigantism?

- rapid growth/tall stature

- concurrent rapid weight gain

- progressive macrocephaly

- large hands/feet, prognathism, coarsened facial features

what is the clinical presentation of acromegaly?

- enlarged hands/feet

- doughy moist handshake

- coarsened facial features

- hyogonadism

- sleep apnea

- DM, HTN, cardiomegaly/LVH

- HA and temporal hemianopia

what are the labs/imaging for gigantism and acromegaly?

- IGF-1 elevated

- OGTT

- PRL, CMP, TSH, free T4

- MRI

what can be found on MRI in gigantism and acromegaly?

pituitary adenoma

what are the ddx for gigantism?

- genetic tall stature

- hyperthyroidism

- chromosomal causes like Kleinfelter/Jacobs/Marfan syndrome

what are ddx for acromegaly?

- genetics

- GH elevations due to kidney/liver failure, malnourishment, meds

what is the treatment of acromegaly and gigantism?

- transsphenoidal surgery for pituitary adenomas

- somatostatin analogs (MC), pegvisomant, cabergoline

- radiation

benign neoplasms that arise from anterior pituitary and are the most common cause of sellar masses 30+ yro

functioning pituitary adenomas

pituitary adenoma > 10 mm =

macroadenoma

1 multiple choice option

pituitary adenoma < 10 mm =

microadenoma

1 multiple choice option

functioning pituitary adenomas can cause ____

hypersecretion of hormones

functioning/non functioning macroadenomas can cause hormone ______ due to compression of other pituitary cells

HYPOsecretion

benign neoplasms that do not cause hormone hypersecretion

nonfunctioning pituitary adenomas

Nonfunctioning microadenomas are usually _____

incidental findings on imaging and asymptomatic

what is the most common functioning pituitary tumor?

prolactinomas

prolactinomas are mostly ______ and common in females

microadenomas

what kind of prolactinoma is most common in males?

macroprolactinoma

what are the symptoms of prolactinomas in males?

- reduced fertility

- reduced libido

- ED

what are the symptoms of prolactinomas in females?

- amenorrhea

- infertility

- galactorrhea

- depression

what are the labs/imaging for prolactinomas?

- elevated serum prolactin

- serum hCG in females

- LH/FSH/testosterone/estradiol

- TSH/free T4

- BMP for renal function

- MRI

what is the MC clinical presentation of pituitary adenomas?

gradual visual defects like bitemporal hemianopsia

hemorrhage or infarction of pituitary in the setting of an adenoma

pituitary apoplexy

what are the sx of pituitary apoplexy?

- sudden HA and vision changes

- AMS

- adrenal crisis

- life threatening hypotension

true/false

there is no treatment for asymptomatic nonfunctioning pituitary microadenoma

true

1 multiple choice option

what is the general treatment of pituitary adenomas that are causing hyper or hyposecretion?

- transsphenoidal surgery

- some need chemo/rad

what is the treatment for prolactinomas?

dopamine agonist like cabergoline

surgery improves hypopituitarism in _____ of patients

50%

four pea-sized glands located at the top and bottom posterior borders of lateral lobes of the thyroid

parathyroid glands

parathyroid glands consist primarily of _____ which synthesize _____

chief cells; PTH

PTH secretion is primarily regulated by _____

- extracellular calcium

- calcium-sensing receptors (CaSR)

very sensitive receptors on the surface of parathyroid cells

CaSR

what does PTH play a major role in?

- bone remodeling

- calcium homeostasis

- renal excretion of phosphate

- activation of vit D

what two other major regulators of calcium does PTH interact with?

- calcitonin (from C cells in thyroid)

- calcitriol (active vit D)

in the kidneys PTH directly stimulates:

- calcium reabsorption

- phosphate excretion

- enzyme to form calcitriol

in the bones PTH directly stimulates:

rapid release of calcium from bone matrix to systemic circulation