Pediatric Endocrinology Flashcards
Growth hormone Deficiency in children
Usually begins in children between 5-8 yrs
- child is normal initially but then falls off the growth curve
- children have no other medical conditions usually and is normal on examination other than weight and height
- children’s parents will both be taller than average usually and they have no reported developmental delays
- growth rate is delayed**
**bone ages are delayed
Screen tests:
- CBC, ESR, electrolytes
- IGF-1/3 levels, somatomedin C and GH levels
- bone age radiographs
- *if a female = get karotype to look for Turner syndrome if present**
Replacement therapy = recombinant GH injections several times per week (need to go to endocrinologist)
Calculation for a rough mid-parental height
- *calculations correct for theopposite gender parents height**
- gives a general estimate for how tall the child should be
Boys [paternal height + (maternal height + 5 inches)]/2 (+/- 2 inches)
Girls [maternal height + (paternal height - 5 inches)]/2 (+/- 2 inches)
if they are way off then check for potential GH deficiency
Bone age definition
Compare the left wrist radiographs in children older than 2 yrs (knee if younger than 2 yrs) to published “normals”
- this determines how old the bones appear compared to chronological age and thus provides an estimate of remaining growth potential of bones
Constitutional growth delay
A condition in which the child’s growth is slower than expected but one or more parents also demonstrated a pubertal developmental delay
- bone age = height age
There is no history or examination of abnormalities
- the growth rate is NORMAL**
Family history is usually positive for at least one “late bloomer” who developed at normal adult height eventually
Familial short statue definition
A short child who is born to short parents who had normal timing of their pubertal development
Kids grow around 3rd-5th percentile at all time, but nothing is technically wrong with them
- bone age = chronological age which means no extra growth potential so no GH replacement fixes this
Growth velocity definition
Increase in measured height or length over time as compared to standardized growth curves
Height age definition
The age at which a child’s measured height is at the 50th percentile
Idiopathic short stature
Condition in which short stature diagnosis cant be reaches
How much growth does someone typically see each year?
1st year of life = 9-11 inches
1-3 yr = 3-5 inch per year
3-puberty = 2-2.75 inch per year
Puberty = 4 inch for guys and 3 inch for girls per year
only time its bad when a kid”falls off the curve” (VERY common in early onset celiac disease also)
Precocious puberty
Excessive growth hormone which produces onset of secondary sexual development before 8 years in girls and 9 years in boys
Can be true = central cause usually pituitary adenomas or CNS lesions
- must rule this out in girls younger than 6-8 yrs and any boy under 9 yrs
Can be pseudopuberty = non-central causes
- gonadotropin independent (usually OCP’s, estrogen/testosterone cream or adrenal/ovarian tumors
Very rare = incomplete
- you get some puberty symptoms but some not
Signs are:
- girls = breast, pubic hair and tall stature for age
- boys = very tall for age and get acne and deep voice quicker
Racial variation of puberty
African Americans = hit puberty earlier
Caucasian’s and Asians = hit puberty later
Delayed puberty definition
No signs of puberty in
- girls by the age of 13
- boys by the age of 14
May be caused by gonadal failure, chromosomal abnormalities, hypopituitarism, chronic disease, malnutrition
Clinical approach to precocious puberty
True precocious puberty overall is more common in girls
- excess secretion of GnRH with normal appearing but early progression of pubertal events
- growth is accelerated and bone age is advanced
However boys are more likely to have a CNS tumor (still like 25% only)
Idiopathic cases are 90% girls
What is the most urgent symptom for precocious puberty?
Vision changes
- can signal mass effect symptoms from somatotropin adenomas
must get an urgent head MRI and initiate prompt referral to pediatric neurosurgeon
Most common Causes of peripheral precocious puberty (no central)
Isolated ovarian cysts/tumors
Exposure to exogenous strokes or androgens
McCune-Albright syndrome
Severe untreated hypothyroidism
CAH
- *abnormal pattern of development of secondary sex characteristics**
- growth is accelerated and bone age is advanced
Benign premature thelarche and adrenarche
Thelarche = breast development without rapid linear growth or other signs of pubertal development observed over a 4-6 month period
- often occurs in girls younger than 2 years
Adrenarche = pubic hair and/or body odor without rapid linear growth
- clitoromegaly, penile growth testicular enlargement. Is observed before age 8 in girls and 9 in boys
- often occurs in African American females
What is estrogenization of the vaginal mucosa?
Becomes dull gray-pink compared to shiny red
Laboratory testing for precocious puberty
Serum estradiol (elevated in girls
Serum testosterone (elevated in boys)
Serum LH
- in noncentral = undetectable
- in central = high
GnRH stimulation test
Bone age radiographs
Consider pelvic UA to check for ovarian tumors/cysts/adrenal tumors
Consider a CT or MRI if central
- pretty much mandatory in all boys
- almost mandatory in all girls under 6 years
Treatment for precocious puberty
goal is to treat this quick enough to prevent premature closure of the epiphyses
GnRH agonists are used for central as first line and often is a good choice for noncentral also
- purpose is to desensitize the gonadotrophic cells in the pituitary to GnRH
- need a pediatric endocrinologist to sign off though
GnRH agonist examples - Leuprorelin - Goserelin - Buserelin “Erelin’s”
Congenital hypothyroidism
Abnormal formation of the thyroid gland (thyroid dysgenesis is the majority of the causes)
Most are detected at within 1st few weeks of birth via screening programs (mandated in all 50 states)
- often asymptomatic at the time but if they are symptomatic
- if severely affected though will manifest symptoms within 1st week of life
Occurs in 1/4000 or 1/2000 births (variable)
Congenital adrenal hyperplasia
Most common cause of ambiguous genitalia
Autosomal recessive disorder that the majority shows 21-hydroxylase deficiency
- causes NO HTN
- causes VIRULIZATION
- also causes electrolyte abnormalities which can be problematic (no aldosterone)
Need to get a karyotype and serum electrolyte levels
- also get serum 17-hydroxyprogesterone levels (this will be high)
Three subtypes:
1) salt wasting (classical form)
- also shows deficiency in aldosterone and is measured by low sodium and high potassium levels
2) simple virilizing form
- mild Deficiency of aldosterone but not enough to show electrolyte abnormalities
3) non classical form
- no ambiguous genitalia and no salt wasting, but there is still cortisol deficiency
- shows late onset premature pubarche and advanced bone age
- females show hirsutism
Girls with CAH are always fertile and therefore must be assigned female sex at birth
need to have an endocrinologist, geneticist, urologist and psychiatrist to help treat
True hermaphodism
About 70% are 46,XX (30% are 46, XY)
- however the majority of these are assigned male gender at birth (75%)
Comprise less than 10% of all intersex cases
- 75% are classified as male at birth because the external genitalia is virilized
Shows:
- bilateral ovotestes (both ovaries and testies)
- testicular tissue that varies in degree of Virilization
Mixed gonadal dysgenesis
Most are 46,XY/45,XO karyotype
- produces testies with sertoli and leydig cells but there is no germinal elements and streak gonads are present (aplastic gonads)
- also produces hypospadias and partial labioscrotal fusion with undescended testes
25% of streak gonads develop malignancy
Female and male pseudohermaphroditism
Female = Produces a 46,XX karyotype and is the largest neonatal group with ambiguous genitalia**
- predominant etiology is CAH
This will show male external genitalia and virulization but ovaries inside and female internal genitalia
Male = produces 46,XY
- predominant etiology is androgen insensitivity syndrome**
- produces female external characteristics with functional testicular tissue and have undescended testes
- diagnosed with primary amenorrhea occurs
What is the serum marker for CAH?
Elevated 17-hydroxyprogesterone
What imaging is needed for androgen and sex disorders?
Pelvic US and pelvic MRI are usually first line
- can give urogential sinus xray with injection if needed
Laparoscopy is usually not needed
Treatment for ambiguous genitalia
First thing needed is to get functionally normal external genitalia by surgery and/or hormones
- emphasis on cosmetic appearance since this can reinforce doubt about sexual identity as early as 6 months
Then work up internal and actual disorder and treat that
Gender assignment
- *in cases in which fertility is not found, depends upon**
- appearance of external genitalia
- potential of unambiguous appearance
- potential for normal sexual functioning
if fertility is determined, then its based on that
Should you do circumsicion on hypospadias patients?
NEVER
Treatment for CAH
Monitor glucose and electrolytes
- give hydrocortisone 10-20 mg/M2 divided 3 doses daily for pretty much life
What are the required physical examination parts to conduct in a patient with precocious puberty
Growth velocity
Skin (examine for cafe-au-lait spots, oiliness and acne)
Presence of axillary hair, body odor and amount of breast tissue
Characteristic of pubic hair via tanner staging
Abdomen for palpable masses
Enlargement of penicillin and thinning of scrotum
Testicle sizes
- if unilateral enlargement = get testicular transillumination to check for hydrocele vs cyst
Neurological exam and potential MRI of th Brian
What are the cut off levels for congenital hypothyroidism screening on infants?
Get a heel stick test on the 2nd or 3rd day of life
TSH normal measurement = <15
TSH 15-29 = measure T4 levels
- if T4 is low = immediate referral to pediatric endocrinologist
TSH 30 or greater = immediate referrals
