Growth & Puberty Flashcards
What does standard deviation tell us?
The variation of results away from the mean
What is a z-score?
The number of standard deviations away from the mean a value is
What percentage of people measured are within 1SD of the mean?
68%
What percentage of people are within 2SD’s of the mean?
95%
What is included on the x and y axes on a normal growth chart?
x-axis: age
y-axis: height and weight
How many readings are required to be plotted on the growth chart to know if the child is growing at a normal rate?
> 1
How can you tell from the growth chart whether a child is growing at a normal rate?
Their plotted height/weight should follow the line trajectory across the ages
Why is it useful to know whether a child has normal measurements and rate of growth?
A child who is growing normally is unlikely to have a major underlying health problem which is causing their presentation
Growth charts have secular trends. What does this mean?
The trend is changing overtime in one general direction
What secular trend is currently being seen in growth charts?
- Increase in child height
- Increase in child weight
- Increase in number of children who are obese
Why is expected weight higher in formula fed babies?
They do not receive the same end of milk signals to stop sucking so tend to feed longer than is necessary
Why is height measurement inaccurate before 2 years of age?
Child is measured lying down so length will change depending on mood e.g., as they kick, scrunch up knees and wriggle around
Measurements on a growth chart should be plotted with a dot and joined up. T/F?
False
Measurements should be plotted with a dot but not joined up
What hormonal change initiates the onset of puberty?
GnRH is released from the hypothalamus and stimulates LH and FSH release
What is the average age that girls and boys enter puberty?
Girls: 11 y/o
Boys: 6 months later
What change in girls signals the onset of puberty?
What change in boys signals the onset of puberty?
Girls: breast buds form
Boys: testicular volume reaches 4ml
Why do people presume that boys enter puberty later than girls? (2)
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
When staging puberty using the Tanner system, at which stage does onset of puberty occur?
Stage 2 out of 5
What characteristics are included in the Tanner staging system in boys vs girls?
Boys:
- Testicular volume
- Presence of pubic hair
- Genital size
Girls:
- Breast development
- Presence of pubic hair
Define:
- Thelarche
- Adrenarche
- Menarche
- Thelarche: breast budding
- Adrenarche: body hair and odour
- Menarche: periods start
Menarche (start of period) usually occurs X years after thelarche (breast budding)
2 years
What is true central precocious puberty (TCPP)?
Is it more common in boys or girls?
Normal pubertal development occurring abnormally early
More common in girls
At what age would puberty be considered precocious in
-girls
-boys
?
Girls: <8 y/o
Boys: <9 y/o
What is pubertal delay? (give ages)
Is it more common in boys or girls?
Absence of secondary sexual development in a girl aged 13+ or a boy aged 14+
More common in boys
On average, at what age do girls vs boys reach their peak height velocity (i.e., growth spurt) during puberty?
Girls: 12 yrs
Boys: 14 yrs
The average height difference between men and women is 12-14.5cm. List 3 reasons for this
- Boys are taller pre-puberty
- Boys have their puberty growth spurt (PHV) later
- Boys have a greater PHV than girls due to increased testosterone
Name two methods that can be used together to predict how tall a child should be when they reach adult height
Adult height predictor (child’s height matched to predicted adult height)
+
Mid-parental centile (predicts child’s adult height based on parent’s height)
What dynamic function test is used to test growth hormone secretion in children?
Clonidine stress test
Clonidine causes hypotension which should trigger GH secretion (safer than insulin tolerance test used in adults)
How is bone age investigated?
The non-dominant hand is x-rayed and the stage of each bone’s maturation is analysed
