Pediatric Endocrine Flashcards
What is the normal rate of linear growth for kids 5-puberty?
At least 5 cm/yr (2 in/yr)
What is the first parameter typically affected in endocrine growth disorders?
Length or height
What is “delayed bone age”?
A bone age that is 2 SDs or more below the chronological age of the patient.
What 4 parameters are included on the growth chart?
Height (or length if <24 mo.)
Weight
BMI (if >36 mo.)
Head circumference (if <24 mo.)
If height/length changes first, think:
If weight changes first, think:
If head circumference changes first, think:
Height - endocrine
Weight - caloric/nutrition
Head circumference - brain/skull/hydrocephalus
What is short stature defined as?
Height atleast 2 SDs below the mean height (50th percentile) for age and sex, which means the height would be less than the 3rd percentile on the growth chart.
What are the following benign causes of short stature?
Familial
Constitutional
Idiopathic
Familial: bone age is consistent w/ chronological age.
-parents are small. They grow with normal velocity in all parameters, but just plot lower on the growth curve.
Constitutional: bone age is delayed (hallmark sign).
-puberty is delayed (late bloomers)
Idiopathic: bone age is consistent w/ chronological age.
-unknown cause
What is the regulation of IGF-1?
It binds to IGFBP-3 and can be transported.
GH increases its synthesis by osteoclasts and chondrocytes, suggesting it plays a role in statural growth.
What levels of IGF-1 and IGFBP-3 would you expect in a patient w/ GH deficiency?
When can these levels be drawn?
Decreased levels of both
At any time of the day - GH is pulsatile however.
What are the 3 most reliable tests for GH stimulation in a patient w/ short stature?
Administration of glucagon
Administration of arginine
Insulin induced hypoglycemia
At what ages does precocious puberty begin in boys vs. girls?
Boys - before 9 y/o
Girls - before 8 y/o
The diagnosis of precocious puberty should be entertained in children who meet the following criteria (boys and girls):
Boys: evidence of testicular and penile enlargement and crossing major percentile lines upward on the linear growth chart.
Girls: progressive breast development and crossing major percentile lines upward on the linear growth chart.
What 4 labs can be checked when considering precocious puberty?
What 3 imaging studies might be of interest?
LH
FSH
Estradiol or testosterone
17-hydroxyprogesterone
Bone age
MRI head (possible CNS tumor)
US of gonads
What regions of the adrenal cortex produce which hormones?
Glomerulosa - mineralocorticoids
Fasciculata - glucocorticoids
Reticularis - sex steroids
Most common cause of ambiguous genitalia in females =
Congenital adrenal hyperplasia (virilization of genitalia)
Symptoms of CAH
Failure-to-thrive Recurrent vomiting Dehydration Hypotension Hyponatremia Hyperkalemia Shock
What are the levels of aldosterone, cortisol and androgens in CAH?
Aldosterone: low
Cortisol: low
Androgens: high
3 mainstays of treatment in an infant in crisis due to CAH
Hydrocortisone (IV or IM)**
Fluids/glucose
Management of hyperkalemia
What are the 3 categories of adrenal gland defects responsible for primary adrenal insufficiency (Addison’s Dz)?
Adrenal dysfunction - ex: autoimmune
Adrenal dysgenesis - ex: congenital adrenal insufficiency
Impaired steroidogenesis - ex: CAH
What is the major lab finding in patients w/ primary adrenal insufficiency?
What are a few others?
Low 8am plasma cortisol + simultaneous elevation of plasma ACTH
Neutropenia
Low Na+
High K+
Fasting hypoglycemia
Low serum ACTH in the setting of low cortisol =
Secondary adrenal insufficiency
Elevated midnight cortisol levels should make you think…
Cushing syndrome
Dexamethasone Suppression Test in Cushing syndrome
Low ACTH + cortisol not suppressed
Primary hypercortisolism (not ACTH driven)
Dexamethasone Suppression Test in Cushing syndrome
High ACTH + cortisol not suppressed
Ectopic ACTH syndrome (associated w/ small cell carcinoma)
