Paediatrics Essay 1: Growth and puberty.

Normal human growth consists of _ phases.

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Recall the four phases of normal human growth.

Fetal growth

Infantile growth

Childhood growth

Pubertal growth

Which is the fastest period of growth?

Fetal growth

What is size at birth determined by?

1. Size of the mother

2. Size of the father

3. Placental nutrient supply (which is dependent on maternal diet) - this modulates fetal growth factors e.g. IGF-2, human placental lactogen and insulin.

4. Growth hormone

What does the 'infantile growth' phase refer to?

Growth during infancy to around 18 months of age.

What is infantile growth determined by?

Adequate nutrition and normal thyroid function.

What does the 'childhood growth' phase refer to?

Growth from 18 months to onset of puberty.

What is childhood growth determined by?

Main determinant:

- Pituitary GH secretion acting to produce IGF-1 at the epiphyses

Adequate nutrition and good health i.e. normal thyroid function, vitamin D etc.

What does the 'pubertal growth' phase refer to?

Growth during the pubertal years.

What is pubertal growth determined by?

Sex hormones (i.e. testosterone, oestradiol) - at the end of puberty these hormones cause fusion of epiphyseal plates, marking the cessation of growth.

Recall some indices used to analyse growth in children.

Length/height

Weight

Head circumference

What is the normal length of a full term newborn?

50cm ± 2cm

Recall the average rate of height/length increase in the first year of life.

3cm/month for the first 3 months.

2.5cm/month during months 3-6

2cm/month during months 6-9

1cm/month from months 9-12.

What is the average increase in length/height by the end of the first year?

25cm

Recall the formula used to estimate the normal length/height of a child at any point in the first year.

Length/height at any point of the first year = Length at birth + (Age in months x 2)

How much does height increase in the second year of life?

10-12cm

How much does the height increase during years 2-3?

8cm

After the age of 3, how much does the height increase per year?

6cm/year

What is considered a concerning growth velocity in children aged above three?

Less than 4cm/year

What is the normal weight of a child born at full term?

2500-4000 grams.

Recall the average rate of weight increase in the first year of life.

25 grams/day in the first 3 months of life.

20 grams/day from months 3-6.

15 grams/day from months 6-9.

12 grams/day from months 9-12.

After the first year, what is the average yearly weight gain?

Approximately 2-2.5kg/year.

If a child is below the 10th centile for height and weight, the child is considered to have ____.

IUGR

How many times should an infant have its weight recorded in the first year of life?

At least 5 times

How many times should a child have his/her weight recorded between years 1-2?

At least 3 times

How many times should children above the age of 2 have their weight recorded per year?

At least once annually.

What is the normal head circumference at birth?

34cm ± 2cm

How much does the head circumference increase in the first year of life?

Increases on average 1cm/month

How much does the head circumference increase during years 1-5?

Increases by 1cm/year

How much does the head circumference increase during years 5-15?

Increases by 0.5cm/year

If a child is below the 3rd percentile for head circumference, what is this called?

Microcephaly

If a child is above the 97rd percentile for head circumference, what is this called?

Macrocephaly

Recall the physiology of puberty.

Hypothalamus secretes GnRH, initially during sleep, then throughout the day in the later stages of puberty

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Stimulates the release of FSH and LH from the pituitary gland

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These hormones act on the target organs:

- Genitourinary ducts

- Hair follicles

- Apocrine sweat glands

- Adipocytes and myocytes

- Bones

- Brain

Also, ACTH stimulates the release of DHEA which leads to pubic and axillary hair.

There is an increase in GH release, leading to growth spurt.

At what age does puberty begin in females?

Usually begins at 8 years old.

When is puberty concluded in females?

Usually by 14 years old.

What is the first sign of puberty in females?

Breast development i.e. a palpable breast disc.

When does this occur?

Begins at 9 years of age but can begin up to 12.5 years.

What occurs almost immediately after breast development?

Pubic hair growth and rapid height growth.

When does the height (growth) spurt reach its maximum in females?

Around age 12

What occurs after the pubic hair growth and height (growth) spurt in females?

Menarche

What is menarche?

The first episode of menstruation.

When does menarche begin?

Around 2.5 years after the start of puberty.

Menarche signals that the ______ is coming to an end, with only around _cm of _______ gain remaining.

Growth

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Height

Besides those already mentioned, recall another change that occurs in females during puberty.

Widening of the hips

At what age does puberty begin in males?

Usually begins at 10 years old.

When is puberty concluded in males?

Usually by 15 years old.

What is the first clinical sign of puberty in males?

Testicular enlargement to over 4ml volume.

How is testicular size measured?

Using an orchidometer

What follows testicular enlargement in males?

Pubic hair growth

When does this occur?

Usually between 10 and 14 years of age

What occurs after the testicular enlargement and pubic hair growth?

Rapid height growth

When does the rapid height growth occur in males?

After a delay of 18 months following testicular enlargement.

In other words, when the testicular volume is 12-15ml.

Besides those already mentioned, recall some other changes that occur in males during puberty.

Deepening of the voice

Facial hair development

Broader shoulders

Penile enlargement

Possibly gynaecomastia

List some common pubertal changes that occur in both sexes.

Development of acne

Axillary hair

Body odour

Mood changes

Sexual feelings/thoughts

How can abnormally early or late puberty be assessed?

Bone age measurement from a hand and wrist X-ray to determine skeletal maturation.

In females, pelvic ultrasound to assess uterine size and endometrial thickness.