Endo Flashcards
Mode of inheritance for 5 alpha reductase
autosomal recessive
Mode of inheritance for androgen insensitivity
x linked recessive
Findings Kallman syndrome
isolated gonadotropin RH def and anosmia (embryo: failure of cells to migrate from olfactory bulb)
Until when to expect spontaneous descent of testes
6 mons
How does lugols solution work
Wolff chaikoff effect
- inhibit organification in thyroid gland
- Effective for 10 days
Half life of thyroid antibodies
12 days (hyperthyroidism from antibodies- up to 3 weeks)
Treatment of choice for neonatal hyperthyroid
methimazole
Findings in thyroxemia of prematurity
Dec TBG- dec T4, T3
Most common cause of congenital hypothyroidism
thyroid dysgenesis (agenesis, partial dysgenesis, extopic)
Time to normalize TFT with treatment
FT4- 3 days; TSH- 2 weeks
Treatment for hyperinsulinism
- Diazoxide (KATP antagonist)
- Octreotide
- Ca channel blocker
- Pancreatectomy
Function of Mg in relation of Ca
- PTH release
- Calcitriol synthesis
- significant at Mg 1.5 mg/dl
Signs of HypoCa secondary to HypoMg
- Tetany
- Seizure
- Weakness
- Prolonged QT
Biochemical features of Osteopenia of prematurity
- hypophosphatemia (<3.5mg/dl)
- Hyperphosphatsia (>800 IU/L)
Treatment for 21-hydroxylase deficiency
mineralocorticoid
glucocorticoid
genital reconstruction
treatment for 11-betahydroxylase
glucocorticoid
genital reconstruction
Findings in Vit D Rickets
pathologic fracture
rachitic rosary
moth eaten metaphases
Lab findings in infant of diabetic mother
- Hypoglycemia (fetal hyperinsulinism)
- Low Mg
- low Ca
Signs of hypoMg
- seizure
- muscle weakness
- decreased DTR
- irritability
- inc QT interval
incidence of infant affected by mat graves
1%
Timing of passing maternal Ab
2nd half of pregnancy
Intrauterine sx of fetal hyperthyroidism
- fetal tachy
- iugr
- hydrops
- goiter
Duration of infantile hyperthyroid from maternal thyroid Ab
4-6 weeks
Embryology of thyroid
4wk- endoderm (pharyngeal floor), four pharyngeal pouch (calcitonin)
8 wk- fetal hypothalamus- TRH but TSH low
10-12 wk- thyroid complete
18-20 wk- thyroid gland func matures, response to TSH, inc T4 only
30 wk- T3 rises
-no fetal inhibition on TSH by T4
- hpt axis func abt 1-2 mos after birth
maternal T4 in cord blood at birth
30-50%
Medication of hypothyroid before and during pregnancy (should be done before the 3rd TM)
Levothyroxine
Effect for hypothyroid in pregnant women to infant
- lower IQ
- Expressive and nonverbal delays
% increase in thyroid hormone in pregnancy
20-50%, inc TBG
Timing of TSH surge in neonate
30 mins after birth then normal 3-5 days
Stimuli for TSH surge
cool extrauterine environment
peak of neonatal T4
48 hours after birth
Pitfall of NBS using TSH
- false pos- ideally 2-4 DOL
- fail to detect TBG def and central hypothyroid
Pitfall of NBS using T4
miss primary hypothyroidism
What is hypothyroxinemia of prematurity
Lower total and FT4 in preterm infant due to:
- abrupt discontinuation of maternal thyroid hormone
- immature HPT axis (dec or absent inc T4 from TSH surge)
- Low TBG
What is sick euthyroid
Low T3 and T4 (T3 more affected) due to inhibition of conversion enzyme
- Mortality assoc with low both TSH, T4 and T3
Complications of maternal Graves disease
- gHTN
- Pre ec
- IUGR
- Preterm birth
Meds affecting TFT
- phenytoin: dec TBG affinity
- dopa: dec TSH
Normal male sexual differentiation

Normal Female Differentiation
- No SRY- ovarian granulosa/ theca cells
- No AMH- mullarian (Cloaca) then into internal female (uterus, fallopian, upper 1/3 vagina), no wolfian
- No testosteron/DHT- clitoris (genital), labia minora (urethral), labia majora (labioscrotal)
Most common cause of genital ambiguity
In 46 XX: CAH
Most common cause of CAH (3)
21-hydroxylase deficiency
11 hydroxylase decificency
3B-hydroxysteroid dehydrogenase
Presentation of 21 hydroxylase def
salt wasting (hyponatremia, hyperkalemia)
hypoglycemia
hypovolemia
shock
Presents as virilization of the mother and the fetus
Aromatase deficiency
- cannot convert androgren precursor to estrogen
Maternal causes of Androgen excess
- ingestion of androgen or progestin
- virilizing adrenocortical tumors
- ovarian tumor
- luteomas
Presentation of vanishing testes or testicular regression
- Before 8 weeks: phenotypic female
- 8-10 weeks: ambigious genitalia
- after 12 weeks: normal male
Presentation of complete androgen insensitivity
Female external genitalia with a blind vaginal pouch
Presents with primary amenorrhea
Initial lab test for all ambigious genitalia
Routine chromosome analysis
-Should be obtained within the 1st 24 hrs after birth
Definition of clitoromegaly
clitoral length >9 mm or width > 6mm
Interpretation of AMH
- reliable marker of testicular function
- Low: vanishing testes, XY gonadal dysgenesis
- Elevated: androgen insensitivity, hypogonadotrophic hypogonadism
Hormones of anterior pituitary gland
- Corticotroph: ACTH
- Thyrotroph: TSH
- Somototroph: GH
- Gonadotroph: LH, FSH
- Lactotroph: Prolactin
- in order of cell differentiation

Embryology of Pituitary Gland
Adenohypophysis: primitive oropharynx (Rathke pouch
Neurohypophysis: Neural ectoderm
Hypothalamus: Diencephalon
- Functional: 12 weeks
- HPA axis: 18-20 weeks
Findings of septo-optic dysplasia
- Optic nerve dysplasia: wandering nystagmus
- midline abnormalities (agenesis of corpus callosum, absence of septum pellucidum
- Pituitary hypoplasia: GH deficiency most common
- 2 of the 3 is needed for Dx
Findings in Pituitary Stalk Interuption
- Thins or interupted pituitary stalk
- absent or ectopic post pit
- small or absent ant pit
- hypoglycemia
- Jaundice
- micropenis
- short fifth digit
- unilateral ptosis
- congenital alopecia
CHARGE syndrome
- Autosomal dominant
-
Coloboma
Heart defect
Atresia coanal
Retardation growth
Genital abnormality
Ear abnormality with sensorial-neural hearing loss - Mutation with CHD7
Most affected pit hormone in childhood
GH defiency
- hypoglycemia
- +/- micropenis
- does not cause IUGR
- Postnatal linear growth not affected until 6-9 mos
Definition of micropenis
- Term: <2.5 cm
- 34 weeks: <2 cm
- 30 weeks: <1.5 cm
Test for GH def
- random GH: > 10 ng/ml adequate
- <5 ng/ml with other of pit defiency findings- GH def
- Done within 1st 7 days
- IGF-1 cannot be used for the 1st 15-18 mos
Findings ACTH deficiency
- hypoglycemina
- hyponatremia without hyperkalemia- cortisol req for water excretion
- cholestasis- def cortisol -> poor bile flow
- failure to thrive
Testing for ACTH def
ACTH or CRH stim test: 3-4 weeks
- Due to placental CRH stim: false normal if done early
Clinical Findings TSH deficiency/ hypothyroidism
- Asymptomatic
- Prolonged jaundice
- Feeding difficulty
- Constipation
- Umbilical hernia
- Macroglossia
- Hypotonia
- delayed reflexes
- Widen ant fontanelle
- Dry skin
Diagnosis of central hypothyroidism
Low FT4 (<0.8 ng/dl) with low or normal TSH
Differential: Sick euthyrodism, Dopamine infusion
Treatment consideration in TSH deficiency
- assess for adrenal deficiency (inc cortisol clearance with thyroid replacement)
- should be treat 48-72 hrs prior to thyroid tx
- with cholestasis: higher doses of levothyrox and hydrocort due to dec absorption
- Discontinue thyroid tx before 3 y/o not recommended
How to administer levothyroxine
- Administer 30 mins before feeds
- absorption inhibited by food and products with soy, iron, calcium, aluminum
- Crushed tablet with 1-2 ml breastmilk, formula or water
- Placed in cheek pad
Pathway for insulin release

Action of insulin
- inc cell glucose uptake
- deposition of glucose as glycogen
- lipogenesis
- inhibition of breakdown of TG (lipolysis), FA (ketogenesis)
- Fetal growth factor
Maintenance of glucose in newborn prior to establish feeds
- glycogenolysis via inc glucagon and epinephrine
- Supress insulin (4-48 hrs)
True or false
gluconeogenesis and ketogenesis is established after birth
False
Rationale for hypoglycemia in
- LBW and IUGR
- IDM/Macrosomia
- decreased glycogen store and low fat stores
- high insulin level, delay glucagon increase
Ideal: with establishment of feeds- normal levels in 48 to 72 hours
counter regulatory hormones of insulin
glucagon- promote glycogenolysis, formation ketone bodies
GH- promotes lipolysis (inc FFA for skeletal and cardiac muscle)
catecholamines- inhibits insulin release and promotes glucagon release
cortisol- inc gluconeogenesis from non carb source: alanine, lactate, glycerol
Outcome for severe/ frequent hypoglycemia
worse executive and visual-motor integration
Etiology of hypoglycemia after 48 hours
- Maternal diabetes (most common transient cause)
- Hyperinsulinism- most common cause of persistent nonketotic hypoglycemia
- transient: stress
- permanent: channelopathies
- hypocortisolism- midline defect
- GH defieciency- midline defect, signs of panhypopituarism
Newborn with persistent hypoglycemia- differential pathway
Most accepted definition of hyperglycemia
Plasma glucose 125 mg/dl
consequences of hyperglycemia
Immediate:
- dehydration
- ketosis
- DKA
- poor growth
- weight loss
- poor pefusion
- susceptibility to infection
Long Term: Neurodevelopment
rationale for consequence of hyperglycemia
- changes in osmolality and blood flow
- endothelial injury
- intracellular acidosis
- inc oxidative stress
Etiology of hyperglycemia
- critical illness
- infection
- stress
- meds (GIR fluids)
- inadeq insulin
Rationale:
inc cytokines, dec glucose utilization, inc gluconeogenesis
Most common defect of permanent DM
KCNJ11 and ABCC8 gene (encode beta-cell subunits of K-ATP channel)
associated with parental consanguinity
Management of hyperglycemia
- Dec GIR
- Correct dehydration
- establish eneteral feeds- inc incretin
- dec IL infusion- dec gluconeogenesis and insulin resistance
- Insulin
ketogenic AA
Leucine
Alanine
Glutamine
What is the mechanism for maternal diabetes teratogenecity
High glucose concentration
- HbA1C- correlate with rate of congenital anomalies
- timing: 2-8 weeks of gestation
- Alteration of DNA methylation
- Inc reactive oxygen species, disordered antioxidant defense
- Inc apoptosis (from distubrance of Ca homeostasis)
Maternal DM and CNS
(most common anomalies)
neural tube defect
holoprosenecephaly hydrocephaly
Maternal DM and Cardiac
(most common defect)
truncus arteriosus
AVSD
heterotaxy
single ventricle
Maternal DM and Craniofacial area
(common affected)
Oculo-Auriculo-Vertebral disorder
- involves abnormalities from the 1st and 2nd pharyngeal arch: ears, eye, vertebral column
orofacial cleft
Maternal DM and GI
(most common associated)
Atresia
Imporforate anus
Ventral wall defect (gastroschisis and omphalocele)
Maternal DM and GU
Hypospadias
renal agenesis/hypoplasia
bladder extrophy
Maternal DM and Musculoskeletal
Caudal regression syndrome
(highest odd ratio)
Prevention of fetal and maternal complication of DM
- HbA1C- < 6.5% pregestation, <6% in gestation
- Closer monitoring: detail anatomy scan at 18 to 20 weeks
- Fetal echo to consider
Definition of metabolic bone disease
reduction of bone mineralization below expected
Characterized by:
- Biochemical:
- Ca <8.5 mg/dl (inadequate intake)
- Phos <3.6 mg/dl
- Alk phos
- <33 wks: > 900 IU/L plus phos <5.6 mg/dl
- <30 wks: >500 IU/L
- Radiographic
- reduced bone mineralization on xray: 20-40%
- Normal: normal bone denisty, normal dense white line
- Grade 1 loss of dense whie line at metaphysis and thining cortex
- Grade 2: fraying metaphysis with splaying (metaphyseal widening) and cupping (rachitic changes)
- Grade 3: fractures
Incidence of MBD
23% VLBW
55% ELBW
Detected at 10-16 weeks postnatal age
Embryology of skeleton
- Begins at 6 weeks
- Pathway:
- craniofacial: cranial neural crest
- axial: paraxial mesoderm
- Limb: lateral plate mesoderm
- Differentiate:
- chondrocyte: cartilage then turns to bone (cartilage frame work done by 8 weeks)
- osteoblast: osteoid bone matrix (mineralization majority at 3rd TM)
Function of osteoblast and osteoclast
Osteoblast:
- secrete osteoid bone matrix (unmineralized bone matrix) forms organic bone after binding with calcium
- differntiate in osteocytes: signal and mechanoreceptor regulate osteoblast and osteoclast (oversight the two cells)
Osteoclast: from hematopoetic stem cell, bone resorption
timing of skeletal mineralization
Majority 3rd trimester
Hormones regulating Mineralization
- Parathyroid
- Vitamin D
- PTH related peptide
- Calcitonin
Effects of PTH
- Affected by dec serum Ca level
- Bone:
- inc osteoclast activity: inc calcium in blood (by upregulate RANKL expression)
- Kidney:
- Inc Ca reaborsption in distal tubule (inc TRPV5 transport)
- Dec phos reabsorption
- Inc active Vit D (1,25 dihydroxy Vit D/ Calcitriol)
What is Vit D
- Active: 1, 25 dihydroxyvitamin D (Calcitriol)
- D2- enteral
- D3- sunlight exposure
- Inc Ca absoprtion
What is PTH related peptide
Inc Ca transfer from placenta
Involved in proper chondrocyte dev endochondral bone formation
Produced by: placenta, parathyroid, muscles
What is Calcitonin
- secreted from thyroid and placenta
- inc calcitriol (Vit D)
- dec osteoclast activity
True or false
Calcium, magnesium and phosphorus is higher in the fetus than the mom
true
Intake of fetus per day of
- Calcium
- Phosphorus
Calcium: 100-120 mg/kg
Phosphorous: 50-65 mg/kg/day
Main source of calcium in the fetus
via active transport across the placenta
Reason for relative hypercalcemia in the fetus (3)
- Low PTH
- Low Calcitriol
- High PTH related peptide
Absorption of Ca in the newborn is by
- Initial passive
- GI matures: active transport via calbindins (Vit-D dependent)
Risk factors for metabolic bone disease (prenatal and post natal)
- Prenatal
- Uteroplacental deficiency ( preeclampsia, IUGR)
- Chorioamnionitis
- Maternal Vit D def
- Male
- Postnatal
- Prematurity- Ca accretion in 3rd TM
- Feeding intolerance
- Vit D def
- Meds (inc excretion): loop diuretics, steroids, caffeine, NaHCO3
- Sepsis
- acidosis
- renal disease
- liver disease
- GI
- Immobility
Monitor sked for MBD
Biochemical at 4 weeks: alk phos and phos then every 2 weeks
Can d/c if: Alk phos <500-600, phos >4 on full feeds
Xray for changes if alk phos >800
What is normal accepted mean blood pressure in preterm infant
2-3 mmHg above the infant post menstrual age
What are the cell origin for the adrenal glands
Adrenal cortex: coelmic epithelium
Adrenal medulla: neural crest
- Components of the mature adrenal gland and early counter part and hormone produced
- Which early counter part contributes most to the size of the mature adrenal at birth
Zona reticularis: fetal zone: androgen
Zona fasiculata: transitional zone: cortisol
Zona glomerulosa: definitive zone: aldosterone
Fetal zone contributes to size at birth
Components of the development of the fetal HPA axis
Pregnant woman
Placenta
Fetus
Early gestation (less than 30 weeks): mom provides the steroids; placenta provides progrestrone
Late gestation (after 30 weeks): inc 11B-HSD in placenta to inactive maternal cortisone; fetus produce own ACTH and cotisol

What is the action of cortisol
metab, stress response, immune and inflam response
Results in: Inc BS, Inc glucagon, Inc catecholamine (via inhibit B receptor breakdown)
Deficiency results in: CLD, cardiovacular instability
Role of Aldosterone
Absorb Na, excrete K
Control BP (inc extracellular fluid volume) via distal collecting tubule
Results in alkalosis (Inc H excretion to balance K absorption)
Role of DHEA and androgenic steroids
Precurssor to estrogen and androgen
DHEA: reduce inflam inc blood flow, immunity, insulin sensitivity, bone metab;
Encourage fetal cortisol production: additional 11B-HSD2 in the placenta
Produced by the fetal zone which disappears by 6-12 mons of age
Presentation of adrenal insuffiency
Vasopressor resistant hypotension
Duration of neonatal graves disease
3 to 5 months
self-limited condition resolves with the clearance of the thyroid receptor antibodies.
When and what to treat with abnormal TFT
Treat ASAP
- Hyperthyroid
- Asymptomatic: methimazole
- Symptomatic methimazole + propanolol
- Hypothyroid
* Levothyroxine
what is the main treatment of choice for diabetes insipidus
thiazide diuretic
think of DI- hypernatremia, polyuria with diluted urine
Mechanism to achieve normothermia in newborns
Nonshivering thermogenesis by oxidation of brown adipose tissue
- has sympathetic innervation, very rich vascularization, and an increased number of mitochondria
- located in the interscapular area, axilla, around the great vessels and kidneys
Management of SIADH
Fluid and sodium restriction
serum sodium is normal for these babies