Normal Growth Flashcards
How do you determine whether you need a further workup for a short child?
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ABSOLUTE HEIGHT < 3RD PERCENTILE
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GROWTH < 2 INCHES A YEAR (AGE 3 YRS TO PUBERTY)
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CROSSING CENTILES DOWNWARD (AFTER TODDLERHOOD AND BEFORE PUBERTY)
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PREDICTED HEIGHT <2SD BELOW EXPECTED FOR TARGET
What can help you distinguish normal growth & abnormal growth?
Check head circumference: if it’s normal but growth isn’t going well, suspect hormonal problem bc nutritional problem would impact head circumference
Obesity v. Cushings or hormone deficiency: in obesity, both height and weight go up; in hormone problem, weight goes up but height doesnt
What’s the abnormal sequence of puberty for girls? boys?
Girls: before age 8 or older than 13
For a boy, everything is pushed 1 year later
In girls, precocious puberty is usally idiopathic/not that bad
In boys, it’s usually pathologic
Bone age
Based on hand x-ray to see epiphyses
Reflects a moment in time
More advanged bone age –> less growth going forward
Normal bone age = chronological age
Predicted height
Average of parents sex adjusted height
girl: dad-13 cm
boy: mom+13 cm
Growth hormone: hypothalmic-pituitary-systemic axis?
GHRH made & released by hypothalamus
Goes to pituitary where GH is made & released
Liver cells & cartilage cells synthesize IGF-I –> growth!
GH action is in bone mtabolism, linear growth, adipose tissue, and muscle
IGF-1 does negative feedback
What can cause postnatal growth failure?
Intrinsic defects of growing tissues i.e. skeletal dysplasias, chondrodystrophies, syndromes
Abnormal environment: metabolic disorders, hypoxia, acidosis, renal insufficiency
Endocrine pathology: abnormal GH or IGF-1 secreiton/action, thyroid hormone deficiency, cortisol excess
How do you test GH levels?
Provacative stimuli: arginine, clonidine, L-DOPA, insulin, glucagon, propranolol, GHRH, etc
Physiologic stimuli: sleep, exercise, hypoglycemia
Interpretation: if they have at least one peak >10 ng/ml = not a GH deficiency
What can cause GH deficiency?
Congenital malformations
Acquired brain tumors
Post trauma or inflammation
Post irradiation
Genetic hypopituaritism
Psychosocial dwarfism
Neurosecretory deficiency
Bioniactive growth hormone
Idiopathic isolated GH deficiency
What are the indications for treatment with GH?
Child: GH deficiency, Turner’s syndrome, Chronic renal insufficiency prior to transplant, prader willi syndrome, IGUR with lack of catch up by age 2 years, severe idopathic short stature
Adults: with GH deficiency, AIDS wasting, short gut synrome
IGF-1
Necessary for post natal growth but not for intrauterine growth
IGF-1 deficiency = Laron syndrome, GH insensitivity/resistance
IGF-1 can be used to treat isolated IGF-1 deficiency, can be used in combo with GH to treat GH deficiency; also may be useful in type II diabetes, ALS
What can cause IUGR?
intrinsic defects: syndromes, skeletal dysplasias
Environmental factors: maternal/placental, nutritional, metabolic
Hormonal: GH, thyroid, insulin and IGF deficiencies/resistance, cortisol excess
IGF-2
Only expressed by the paternally derived chromosome 11
Tissue specific expression
High fetal levels –> overgrowth (Beckwith Wiedemann Syndrome)
Low fetal levels –> IUGR (Russel Silver Syndrome)
What are the therapeutic options for tx of short stature?
GH
IGF-1
Androgens
Low dose estrogen
Lupron
Aromatase inhibitors
