2/15 Growth - Radovick

Question 1

timing of peak growth velocity in boys and girls during puberty

Answer 1

DIFFERENT!!!

peak in growth velocity associated with secretion of sex steroids

• girls : 12y : 8-10cm
• boys : 14y : 9-11cm

→→→ diffs in adult height

*anything that affects growth axis → can affect final height

Question 2

classification of short stature

Answer 2

1. “normal” variants

• familial short stature
• constitutional delay of growth

2. pathological variants

• disproportionate → genetic and bone abnlities
• proportionate

3. idiopathic short stature (i.e. everything else

Question 3

normal variants of short stature

Answer 3

1. familial short stature

• short stature in family
• nl growth rate
• nl age of puberty
• nl bone age

2. constitutional delay of growth

• temp reduction in growth rate for age, but can reach nl height
  
  • delay in age of puberty
  • delayed bone age

Question 4

pathological variants of short stature

Answer 4

1. disproportionate

• rickets
• skeletal dysplasia (osteogenesis imperfecta)

2. proportionate

• prenatal
  
  1. IUGR
  2. genetic syndromes
  3. defects in pituitary devpt
• postnatal
  
  1. malnutrition
  2. chronic disease
  3. psychosocial dwarf
  4. endocrine disease

3. idiopathic : dx of exclusion

• short BUT no short relatives, no fhx of pubertal delay, all endocrine testing normal

Question 5

growth hormone deficiency

normal axis

abnormalities at level of ant pit

Answer 5

hypothal:GHRH → ant pituitary:GH → liver:IGF1 (insulin-like growth factor) → bone/muscle

abnormalities at level of…

• ant pituitary
  
  • GHRHreceptor mutations
  • GH gene mutations
  • CPHD (combined pituitary hormone deficiency)

Question 6

GH resistance

IGF1 deficiency/resistance

Answer 6

mutations at the level of…

• liver
  
  • GHreceptor mutations (Laron dwarves)
  • STAT mutations
  • IGF1 mutations
• bone
  
  • IGF1receptor mutations

Question 7

GH deficiency

severe vs mild

Answer 7

severe def?

• maybe assoc with multiple ant pituitary hrmone deficits
• characterized in newborn period by:
  
  • hypoglycemia
  • small phallus in boys

mild def?

• usually presents at 6mo+ w subnormal growth rate → proportionate short stature
• cherubic appearance w incr body fat ant:
  
  • decr muscle mass
  • delayed dentition
  • thin hair
  • poor nail growth

Question 8

GH deficiency

Answer 8

• auxiologic
  
  • height >2SD below mean
  • growth rate <50percentile for age
  • crossing percentiles on height curve
• bone age delayed
• lab assay: IGF1, IGFBP3
• provocative testing for GH
• brain MRI

Question 9

tx of GH deficiency

Answer 9

• initiate tx asap
• GH subcutaneously
• growth rate will accelerate to normal during first year
• cont tx until satisfactory height acheived or epiphyseal fusion occurs

FDA approved uses (pic)

Question 10

summary

Answer 10