Growth & Puberty

Question 1

What does standard deviation tell us?

Answer 1

The variation of results away from the mean

Question 2

What is a z-score?

Answer 2

The number of standard deviations away from the mean a value is

Question 3

What percentage of people measured are within 1SD of the mean?

Answer 3

68%

Question 4

What percentage of people are within 2SD’s of the mean?

Answer 4

95%

Question 5

What is included on the x and y axes on a normal growth chart?

Answer 5

x-axis: age

y-axis: height and weight

Question 6

How many readings are required to be plotted on the growth chart to know if the child is growing at a normal rate?

Answer 6

> 1

Question 7

How can you tell from the growth chart whether a child is growing at a normal rate?

Answer 7

Their plotted height/weight should follow the line trajectory across the ages

Question 8

Why is it useful to know whether a child has normal measurements and rate of growth?

Answer 8

A child who is growing normally is unlikely to have a major underlying health problem which is causing their presentation

Question 9

Growth charts have secular trends. What does this mean?

Answer 9

The trend is changing overtime in one general direction

Question 10

What secular trend is currently being seen in growth charts?

Answer 10

• Increase in child height
• Increase in child weight
• Increase in number of children who are obese

Question 11

Why is expected weight higher in formula fed babies?

Answer 11

They do not receive the same end of milk signals to stop sucking so tend to feed longer than is necessary

Question 12

Why is height measurement inaccurate before 2 years of age?

Answer 12

Child is measured lying down so length will change depending on mood e.g., as they kick, scrunch up knees and wriggle around

Question 13

Measurements on a growth chart should be plotted with a dot and joined up. T/F?

Answer 13

False

Measurements should be plotted with a dot but not joined up

Question 14

What hormonal change initiates the onset of puberty?

Answer 14

GnRH is released from the hypothalamus and stimulates LH and FSH release

Question 15

What is the average age that girls and boys enter puberty?

Answer 15

Girls: 11 y/o
Boys: 6 months later

Question 16

What change in girls signals the onset of puberty?

What change in boys signals the onset of puberty?

Answer 16

Girls: breast buds form
Boys: testicular volume reaches 4ml

Question 17

Why do people presume that boys enter puberty later than girls? (2)

Answer 17

Changes which signal the start of puberty (testicular volume increase) are less obvious than changes in girls

Girls also have their pubertal growth spurt earlier

Question 18

When staging puberty using the Tanner system, at which stage does onset of puberty occur?

Answer 18

Stage 2 out of 5

Question 19

What characteristics are included in the Tanner staging system in boys vs girls?

Answer 19

Boys:

• Testicular volume
• Presence of pubic hair
• Genital size

Girls:

• Breast development
• Presence of pubic hair

Question 20

Define:

• Thelarche
• Adrenarche
• Menarche

Answer 20

• Thelarche: breast budding
• Adrenarche: body hair and odour
• Menarche: periods start

Question 21

Menarche (start of period) usually occurs X years after thelarche (breast budding)

Answer 21

2 years

Question 22

What is true central precocious puberty (TCPP)?

Is it more common in boys or girls?

Answer 22

Normal pubertal development occurring abnormally early

More common in girls

Question 23

At what age would puberty be considered precocious in
-girls
-boys
?

Answer 23

Girls: <8 y/o
Boys: <9 y/o

Question 24

What is pubertal delay? (give ages)

Is it more common in boys or girls?

Answer 24

Absence of secondary sexual development in a girl aged 13+ or a boy aged 14+

More common in boys

Question 25

On average, at what age do girls vs boys reach their peak height velocity (i.e., growth spurt) during puberty?

Answer 25

Girls: 12 yrs
Boys: 14 yrs

Question 26

The average height difference between men and women is 12-14.5cm. List 3 reasons for this

Answer 26

• Boys are taller pre-puberty
• Boys have their puberty growth spurt (PHV) later
• Boys have a greater PHV than girls due to increased testosterone

Question 27

Name two methods that can be used together to predict how tall a child should be when they reach adult height

Answer 27

Adult height predictor (child’s height matched to predicted adult height)
+
Mid-parental centile (predicts child’s adult height based on parent’s height)

Question 28

What dynamic function test is used to test growth hormone secretion in children?

Answer 28

Clonidine stress test

Clonidine causes hypotension which should trigger GH secretion (safer than insulin tolerance test used in adults)

Question 29

How is bone age investigated?

Answer 29

The non-dominant hand is x-rayed and the stage of each bone’s maturation is analysed