Endocrinology Flashcards
Default pattern of differentiation of the genital system
Phenotypic female
Result of presence of androgens
Male external genitals
Result of presence of mullerian inhibiting factor
Regression of Female internal duct structures
Sequence of male pubertal development
Testicular growth
Pubarche
Penile growth
Peak height velocity
First sign of pubertal development in males
Testicular enlargement
Sequence of female pubertal development
Thelarche (breast)
Pubarche
Peak height velocity
menarche
Age of delayed puberty
Boys: 14 yo
Girls: 13 yo
Most likely cause if delayed puberty in boys
Constitutional delay
Premature adrenarche
Androgenic sexual characteristics (hair, acne, odor) without estrogenic sexual characteristics (breast, menarche)
Premature thelarche
Before 8 yo
Premature testicular growth
Before 9 yo
Precocious puberty
Cafe-au-lait with jagged borders
Fibrous dysplasia (radiolucent regions on bone)
McCune Albright syndrome
Phenotypic female
Genetic male (XY)
No male external genitalia
Blind vagina
No uterus
X-linked
Androgen insensitivity syndrome
Most common cause of adrenal insufficiency in infants
Congenital adrenal hyperplasia
No ambiguous genitalia in males
Excessive scrotal pigmentation
Ambiguous genitalia and No palpable testes in females
Posterior labial adhesions
Clitoral hypertrophy
Congenital adrenal hyperplasia
Most common cause of CAH
21-hydroxylase deficiency
First-line diagnostic test for CAH
17-hydroxyprogesterone levels
(Elevated with 21-hydroxylase deficiency)
Management for CAH
Dextrose containing fluids
Mineralocorticoids (fludracortisone)
Corticosteroids (hydrocortisone)
Hyperpigmentation
Hyperkalemia
Hyponatremia
High ACTH
Primary adrenal deficiency
Midline defects
Low ACTH
Secondary adrenal insufficiency
Diagnosing and managing primary and secondary adrenal insufficiency
AM cortisol
-if < 3, confirmed primary
-if 3-15, do ACTH stim test
ACTH stim test
-if cortisol < 18 — primary
-if cortisol > 18 — secondary
Primary - hydrocortisone + fludricortisone
Secondary - hydrocortisone (function normal)
Most common cause of Cushing syndrome
Exogenous steroids
Gold standard for confirming hypercorticolism
24-hour urinary free cortisol excretion
> 100mcg/day — confirms Cushing’s
Work up for Cushing’s
24 hr free urinary cortisol
Or late night salivary/plasma cortisol
Or Dexamethasone suppression test
Next step If urine free cortisol elevated
Serum ACTH level
-if elevated — MRI head
-if low — MRI adrenals
Diabetes insipidus
Exophthalmus
Lytic bone lesions
Recurrent otitis media
Langerhans Cell Histiocytosis
(Posterior pituitary disease)
Time if peak growth velocity
Around SMR 3 in boys and girls
Peak growth velocity for girls
1.5 years before menarche at SMR3
2 correct scenarios for growth hormone deficiency
Space-occupying lesion
Congenital
Micropenis
Hypoglycemia
Short stature
SOD
breech presentation
Jaundice
Congenital growth hormone deficiency
(Typically around 6-12 mo)
Decrease in growth rate
Early teen
Delayed onset of puberty
Bone age below chronological age
Constitutional growth delay
Best assessment for constitutional growth delay
Compare bone age to chronological age
(Bone < chronological)
Disproportionate short stature
Achondroplasia