Pediatric Endocrine Flashcards
describe the pathogenesis of Rickets
failure of apoptosis of the hypertrophic chondrocyte in the physeal growth plates leading to a cupping appearance of the epiphyseal ends of the bone
Describe the pathogenesis of hypophosphatemic rickets
X-linked genetic disorder of PHEX gene which encodes for FGF-23
T or F: maternal diabetes can cause the baby to grow faster b/c of increased GH and insulin
True
what would happen if a pregie has undiagnosed parathyroid adenoma?
Hypersecretion of PTH will increase serum calcium in the mother and subsequently that of the fetus
Effect: decreased fetal PTH secretion and hypocalcemia
what are the clinical presentations of congenital hypothyroidism?
6 Ps:
pot-belly
pallor
puffy-face
protruding umbilicus
protuberant tongue
poor brain development
what are the lab indications of primary hypothyroidism?
High TSH & low free T4
explanation: TSH is compensating for low T4 levels
what are the lab indications of secondary or central hypothyroidism?
low TSH & low T4
what compound in serum is used to evaluate GH deficiency?
IGF-1
What should you as the physician include in your initial work-up for evaluation of GH deficiency?
IGF-1
if IGF-1 elevated to GH suppression test and MRI of pituitary gland to rule out craniopharyngioma
Define constitutional growth delay.
benign transient delay in growth that eventually catches up w/ growth and sexual developmental stages
what is the main cause of chronological age > bone age?
GH deficiency
what is the main cause of bone age > chronological age?
obesity
Describe how obesity affects the growth plates?
obesity increases amount of estrogens due to increased aromatase activity in the presence of excess adipose tissue
estrogen inhibits apoptosis in bone-forming osteoblasts and induces apoptosis in bone-resorbing osteoclasts
T or F: continuous release of GnRH stimulates subsequent release of LH & FSH.
FALSE
continuous release of GnRH inhibits release of GH & FSH
GnRH promotes LH & FSH release when released in a pulsatile manner
Define Gonadarche
increased GnRH secretion in response to nocturnal LH secretion
Prior to puberty, how are androgens produced?
androgens get synthesized from cholesterol in the adrenal gland and converted to estrogen by aromatases in adipose tissues.
what is primary hypergonadotropic hypogonadism?
defined quantitatively as elevated gonadotropins but low sex steroid levels
Define hypogonadotropic hypogonadism
low gonadotropin concentrations and low levels of sex steroid
what are the most common causes of primary hypogonadism
Turner syndrome
klinefelter syndrome
what are the most common causes of secondary hypogonadism?
constitutional delay of puberty
Kallmann syndrome
what heart defects are assoc. w/ Turner Syndrome?
coarctation of the aorta
bicuspid aortic valve
compare and contrast the different clinical presentations b/t Turner and Klinefelter syndromes.
Turner syndrome:
short stature
decreased estrogen
increased LH & FSH
ovarian dysgenesis
Klinefelter Syndrome:
tall stature
decreased testosterone
increased estrogen, LH, FSH
testicular atrophy
gynecomastia
female hair distribution
what is the pathogenesis of Kallmann syndrome
failed migration of GnRH-producing neurons
what are the clinical presentations of Kallmann syndrome
Anosmia
infertility
primary amenorrhea in females
lack of testicular development in males
decreased LH, FSH, & testosterone
failure to start or complete puberty
What facet of turner syndrome explains assoc. heart defects?
decreased estrogen:
estrogen acts on the heart to increase vasodilation and nitric oxide production
this prevents the extensive aortic stiffness seen in the hearts of kids w/ turner syndrome
What is the pathogenesis of central precocious puberty
Early activation of HPA axis leading to increased FSH, LH, & subsequently estrogen
describe the pathogenesis of peripheral precocious puberty
suppressed HPA axis leading to decreased FSH, LH, but increased estrogen
what is the pathogenesis of McCune-Albright Syndrome
GNAS gene defect stimulates adenylate cyclase enzymes
what are the clinical manifestations of MA syndrome?
mosaicism- unilateral Cafe-au-lait spots
fibrous dysplasia of the bones
precocious puberty
what is the treatment for central precocious puberty
long-acting GnRH analogs like Leuprolide
what is the treatment for peripheral precocious puberty
antiandrogens, aromatase inhibitors, antiestrogens
Describe the pathogenesis of craniopharyngiomas
Failure of the Rathke’s pouch to obliterate specific tissues during development of the anterior pituitary
where are craniopharyngiomas located
suprasellar area of the brain
what are clinical manifestations of craniophyaryngiomas?
temporal hemianopsia, GH deficiency, Diabetes Insipidus
what are the clinical presentations of congential panhypopituitarism
hypoglycemia, Jaundice, high pitched voice, proportional extremities, delayed sexual maturation, small saddle shaped nose
what are the clinical hallmarks of central diabetes insipidus?
nocturia, polydipsia, dehydration, hypotension, decreased urine osmolarity, increased plasma osmolarity, hypernatremia
what is the 1st line drug for treatment of SIADH?
Tolvaptan
T or F: there is a tanner stage 1 exclusively for males
false
Describe Tanner stage 1 that applies to both sexes
no sexual hair in pubic area
pre-pubertal stage
Describe the pre-pubertal tanner stage 1 that applies exclusively to females
flat-appearing chest with raised nipple
Tanner Stage 2 normally occurs throughout what age-range?
8-11.5 yrs.
What is tanner stage II for males and females respectively?
both sexes: pubic hair appears
males: testicular enlargement
females: formation of breast buds
What is tanner stage III for males and females respectively?
both sexes: coarse hair across pubis sparing thigh
males: penis width/glans
females: breast enlargement
When does Tanner stage III normally occur?
11.5-13 yrs.
Describe Tanner Stage IV
same as Stage III with the addition of raised areola for females
when does tanner stage IV normally occur?
13-15 yrs.
What happens during stage V tanner
both sexes: coarse hair across pubis and medial thigh
males: penis and testis enlarge to adult size
females: adult breast contour, areola flattens
Tanner stage 5 does not typically occur until when?
pt. > 15 yrs. old
When confirming a diagnosis of congenital adrenal hyperplasia, you would expect to see increased serum levels of what?
17-OHP: for CYP21 mut.
11 deoxycortisol: for CYP11 mut.
T or F: 21-hydroxylase is only involved in the production of mineral and glucocorticoids
true
CYP 21 does not influence androgen production which will increase androgen production
what are the clinical presentations of CAH (specifically 21-OH deficiency)
ambiguous genitalia
lethargy
hypotension
salt-wasting
virilization
early height acceleration followed by later short stature
what are lab findings for 21-OH CAH?
hyponatremia
hyperkalemia
hypoglycemia
elevated 17-OHP
why does 11beta-OH deficiency cause HTN?
b/c 11B-OH is only involved in synthesis of cortisol, androgen and aldosterone production increase
T or F: 17alpha-OH is only involved in androgen production.
False
17A-OH does not affect mineralocorticoid production
it is however, the first enzyme involved in the conversions to make cortisol and estradiol
In primary adrenal insufficiency, what part of the adrenal glands are affected first?
zona fasciculata
What are early signs of Type I DM?
weight loss, lethargy, polydipsia, polyurina, fruity odor urine, polyphagia, N/V, abdominal pain, hyperventilation
what are the lab findings assoc. w/ Type I DM?
very low bicarb
high Cr & BUN
hyperglycemia
positive urinary ketones (acetoacetate)
positive serum B-hydroxybutyrate
Why do pt. w/ DKA typically present w/ hyponatremia?
hyperglycemia increases plasma osmolarity resulting in osmosis from the ICM to the ECM
what effects does high blood sugar have on potassium regulation?
potassium can be lost through emesis
potassium wasting due to elevated aldosterone and osmotic diuresis
what effects does DKA have on phosphate regulation?
phosphate wasting-glucosuria induced osmotic diuresis
metabolic acidosis shifts phosphate out of cells
DKA causes what metabolic disorder
Metabolic Acidosis w/ comp. Resp. alkalosis
increased anion gap
T or F: the severity of DKA is categorized by acid-base statues?
true
what should be done prior to insulin admin. for a pt. w/ DKA?
IVF to promote volume expansion
effect: increased renal perfusion & decreased glucose concentration in blood
List the clinical triad of cerebral edema?
irregular breathing
HTN
bradycardia
T or F: most diabetes related deaths are due to cerebral injury.
True
What is the medical managment for cerebral edema
mannitol IV and oxygen as needed
intubation for resp. management
What should be monitored for pts. w/ Type 1 DM?
BP
Lipid metabolism
retinopathies
nephropathies
neuropathies
pts. w/ Type 1 DM are at high risk for what
HYPOGLYCEMIA
what is the treatment for hypoglycemic shock?
glucagon
what conditions can cause hypoglycemia in pts. w/ Type I DM
illness
exercising
forgetting to eat
T or F: pts. w/ Type II DM have a much higher risk of developing DKA compared to pts. w/ Type I DM
FALSE
What medical emergency, although rare, is implicated for pts. w/ both Type I & II DM
hyperosmolar hyperglycemia
unlike DKA, T2DM-absecne of ketones
