Pediatric Endocrine

Question 1

What is the normal rate of linear growth for kids 5-puberty?

Answer 1

At least 5 cm/yr (2 in/yr)

Question 2

What is the first parameter typically affected in endocrine growth disorders?

Answer 2

Length or height

Question 3

What is “delayed bone age”?

Answer 3

A bone age that is 2 SDs or more below the chronological age of the patient.

Question 4

What 4 parameters are included on the growth chart?

Answer 4

Height (or length if <24 mo.)
Weight
BMI (if >36 mo.)
Head circumference (if <24 mo.)

Question 5

If height/length changes first, think:

If weight changes first, think:

If head circumference changes first, think:

Answer 5

Height - endocrine

Weight - caloric/nutrition

Head circumference - brain/skull/hydrocephalus

Question 6

What is short stature defined as?

Answer 6

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.

Question 7

What are the following benign causes of short stature?

Familial

Constitutional

Idiopathic

Answer 7

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

Question 8

What is the regulation of IGF-1?

Answer 8

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.

Question 9

What levels of IGF-1 and IGFBP-3 would you expect in a patient w/ GH deficiency?

When can these levels be drawn?

Answer 9

Decreased levels of both

At any time of the day - GH is pulsatile however.

Question 10

What are the 3 most reliable tests for GH stimulation in a patient w/ short stature?

Answer 10

Administration of glucagon
Administration of arginine
Insulin induced hypoglycemia

Question 11

At what ages does precocious puberty begin in boys vs. girls?

Answer 11

Boys - before 9 y/o

Girls - before 8 y/o

Question 12

The diagnosis of precocious puberty should be entertained in children who meet the following criteria (boys and girls):

Answer 12

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.

Question 13

What 4 labs can be checked when considering precocious puberty?

What 3 imaging studies might be of interest?

Answer 13

LH
FSH
Estradiol or testosterone
17-hydroxyprogesterone

Bone age
MRI head (possible CNS tumor)
US of gonads

Question 14

What regions of the adrenal cortex produce which hormones?

Answer 14

Glomerulosa - mineralocorticoids

Fasciculata - glucocorticoids

Reticularis - sex steroids

Question 15

Most common cause of ambiguous genitalia in females =

Answer 15

Congenital adrenal hyperplasia (virilization of genitalia)

Question 16

Symptoms of CAH

Answer 16

Failure-to-thrive
Recurrent vomiting
Dehydration
Hypotension
Hyponatremia
Hyperkalemia
Shock

Question 17

What are the levels of aldosterone, cortisol and androgens in CAH?

Answer 17

Aldosterone: low
Cortisol: low
Androgens: high

Question 18

3 mainstays of treatment in an infant in crisis due to CAH

Answer 18

Hydrocortisone (IV or IM)**

Fluids/glucose

Management of hyperkalemia

Question 19

What are the 3 categories of adrenal gland defects responsible for primary adrenal insufficiency (Addison’s Dz)?

Answer 19

Adrenal dysfunction - ex: autoimmune
Adrenal dysgenesis - ex: congenital adrenal insufficiency
Impaired steroidogenesis - ex: CAH

Question 20

What is the major lab finding in patients w/ primary adrenal insufficiency?

What are a few others?

Answer 20

Low 8am plasma cortisol + simultaneous elevation of plasma ACTH

Neutropenia
Low Na+
High K+
Fasting hypoglycemia

Question 21

Low serum ACTH in the setting of low cortisol =

Answer 21

Secondary adrenal insufficiency

Question 22

Elevated midnight cortisol levels should make you think…

Answer 22

Cushing syndrome

Question 23

Dexamethasone Suppression Test in Cushing syndrome

Low ACTH + cortisol not suppressed

Answer 23

Primary hypercortisolism (not ACTH driven)

Question 24

Dexamethasone Suppression Test in Cushing syndrome

High ACTH + cortisol not suppressed

Answer 24

Ectopic ACTH syndrome (associated w/ small cell carcinoma)

Question 25

Dexamethasone Suppression Test in Cushing syndrome

NL/mildly elevated ACTH + cortisol only suppressed at high doses

Answer 25

Cushing disease (pituitary cause)

Question 26

3 features of primary aldosteronism

Answer 26

Low renin HTN
Hypokalemia
Metabolic acidosis

Question 27

VHL type 2 inheritance:

What do 20% of patients develop?

Patients will have: (3)

Answer 27

AD

Pheochromocytomas

Retinal capillary hemangiomas/hemangioblastomas (BV tumors)
Hemangioblastomas of CNS
Increased risk for renal cysts that may become RCC

Question 28

Patients w/ adrenal incidentalomas require testing for what? (3)

At what size should they be resected?

Answer 28

Cushing syndrome
Hyperaldosteronism
Pheochromocytoma

If > 4 cm