• Growth – an increase in size, implying an increase in length or height as opposed to weight
• Chronological Age – age since birth
• Height Age – the age at which a given height would be the average (as plotted on a growth chart)
• Bone Age – determined by x-rays of the left wrist, a reflection of maturation of bone, gives an idea of growth potential
• Growth Potential – how much growth is possible, from x-ray measurements of the physis
• Upper to Lower Segment Ratio – (U/L), length of upper segment divided by length of the lower segment
• upper and lower segments are from the symphysis pubis and extend up or down accordingly.
• Newborn – 1.7
• Age 10 – 1.0
• Adult – 0.85

• Three zones of rapid growth
• (1) last trimester of gestation – size of uterus and pathological conditions in fetus matter more than genetics
• (2) first two years of life – growth rate during this period can vary greatly and still be "normal"
• (3) "adolescent growth spurt"
• the growth rate is abnormal at any non-adult age if it falls below 5 cm/year
• Growth Percentile Channel – curved line on height vs. age graph showing average normal growth rate
• an infant may shift growth percentile channels, a child >2y.o. should stay in one channel, if not something is wrong

• Prenatal – due to maternal and uterine factors as well as hormones (but usually not T₄ or GH) – example: EtOH
• Intrauterine Growth Retardation (IUGR) – at least 2 std deviations below normal full term birth weight
• Two Possible outcomes:
• (1) permanently short stature (30%)
• (2) catch-up growth (70%)
• Postnatal
• Genetic – normal variants and syndromes
• Familial short stature – bone age = chronological age, small parents = small children, normal variant
• Constitutional delay (late bloomer) – bone age < chronological age parents were late bloomers, normal variant
• Turner’s syndrome – 45X (only one X), webbed neck, coarctation of the aorta –any short girl should be karyotyped
• Height age < bone age < chronological age
• Nutritional – #1 cause of proportionate short stature, height falls off growth curve after weight falls off.
• Chronic illness
• Psychosocial – deprivation dwarfism, when pituitary shuts off in response to an environment
• Hormones – thyroid hormone (drastic effects), growth hormone (GH), excess glucocorticoids

• Physiological – familial short stature or constitutional delay (see above)
• Pathological
• Proportionate – normal upper to lower body segment ratio
• Malnutrition
• Chronic Disease – often growth failure is the first sign of a chronic disease process in children
• Hypothyroidism – often proportionate, most likely Hashimoto’s with few other symptoms
• Cushing’s syndrome – any excess of glucocorticoids above physiologic levels will stunt growth
• Growth Hormone Deficiency – "proportional dwarfism" – cubby with low muscle mass, will reach normal height with treament, can be congenital or acquired (falls off growth chart), probably tumor if acquired
• Disproportionate – abnormal upper to lower body segment ratio
• Achondroplasia – big head and short limbs – autosomal dominant, many are new mutations, can reproduce Hypothyroidism – delayed bone age, short arms
• Radiation effects – radiation to the spine will cause the spine to fuse and limit growth of the trunk
• In general, if short stature has endocrine causes Þ cubby children; if non-endocrine causes Þ thin children***

 Tall children

• Normal Variants – constitutional, bone age = chronological age
• Genetic
• Marfan’s Syndrome, abnomral upper to lower body segment ratio
• Endocrine
• GH excess – Height age > Bone age, Bone age = Chronological age
• Androgen excess – bone age > chronological age, precocious puberty
• Estrogen excess – bone age > chronological age, early fusion of physis so short at adulthood despite early excess growth, excess estrogen will produce gynecomastia in boys