12 - Fundamental mechanisms in human growth and puberty

Question 1

What are the requirements for normal human growth?

Answer 1

• Absence of chronic disease
• Emotional stability, secure family environment
• Adequate nutrition
• Normal hormone/growth factor actions
• Healthy growth plates

Question 2

What are the phases of growth?

Answer 2

Infancy
Childhood
Puberty

Question 3

What occurs during infancy in terms of growth?

Answer 3

o Nutrition most significant source of growth

o 25cm/year

Question 4

What occurs during childhood in terms of growth?

Answer 4

o Growth hormone and T4 most significant

o 4-8cm/year

Question 5

What occurs during puberty in terms of growth?

Answer 5

o Sex steroids, growth hormone and T4 most significant

o Peak at 8-12cm/year

Question 6

What are short stature disorders?

Answer 6

growth hormone deficiency and Turner syndrome

Question 7

What are elements of well-functioning monitoring?

Answer 7

o	Calibrated equipment 
o	Correct technique 
o	Systematically collected growth data 
o	Screening rules for abnormal growth 
o	Referral criteria 
o	Adherence to guidelines 
o	Appropriate diagnostic work up

Question 8

What are centiles?

Answer 8

o Optimum range of weights and heights
o 50% below 50th
o half between 25-75
o 50th centile de-emphasised

Question 9

When would a child need further assessment?

Answer 9

o Weight or height below 0.4th centile
o Height centile more than 3 centile spaces below the mid-parental centile
o Drop in height centile position of more than 2 centile space

Question 10

What is bone age used for?

Answer 10

adult height prediction

Question 11

What is short stature defined as?

Answer 11

the length or height less and 2 standard deviations below the mean for the age and sex of appropriate reference population

Question 12

What causes proportionate short stature?

Answer 12

	Psychosocial growth retardation 
	Turner syndrome 
	Chronic renal insufficiency 
	GI disease
	Nutritional deficiency 
	Hypothyroidism 
	Hypercortisolism

Question 13

What causes disproportionate short stature?

Answer 13

 Achondroplasia
 Hypochondroplasia
 Rickets

Question 14

What are the mean ages for somatic changes during puberty for girls and boys?

Answer 14

11 for girls and 12 for boys

Question 15

Where is GnRH released from?

Answer 15

Hypothalamus

Question 16

How does GnRH release change during pregnancy?

Answer 16

o Some release during gestation for sexual maturation
o Large activation in infancy
o Long latent period during childhood
o Reactivation during puberty

Question 17

What does GnRH stimulate?

Answer 17

LH and FSH production from the anterior pituitary

Question 18

What are the tanner stages?

Answer 18

staging of somatic changes during puberty
o Onset of puberty defined as Tanner stage B2 for girls (budding of the breast) and stage G2 for boys (testis volume > 3mL)

Question 19

When does peak height velocity occur for girls and boys?

Answer 19

early stage for girls and mid stages for boys

Question 20

What is the difference in adult height?

Answer 20

o 13cm difference in adult height
 2 additional years of prepubertal growth
 Taller prepubertal height
 Greater amplitude of spurt in males