Growth and Puberty Flashcards
What are the four phases of normal human growth?
Fetal, the infantile phase, childhood phase and the pubertal growth spurt
What is the size at birth determined by?
The size of the mother and by placental nutrient supply
What is growth during the infantile phase determined by?
Adequate nutrition, good health and normal thyroid function
What is failure to thrive?
Inadequate rate of weight gain during the infantile phase
What is growth during the childhood phase largely determined by?
Pituitary growth hormone secretion acting to produce IGF-1 at the epiphyses is the main determinant of a child’s rate of growth, provided there is adequate nutrition and good health.
What can negatively affect growth during the childhood phase?
Thyroid hormone, vitamin D and steroids. Profound chronic unhappiness can decrease GH secretion and accounts for psychosocial short stature
What causes the pubertal growth spurt?
Sex hormones, mainly testosterone and oestradiol, cause the back to lengthen and boost GH secretion
What stops growth?
Testosterone and oestradiol cause fusion of the epiphyseal growth places and a cessation of growth, so patients that suffer from early puberty may be short
How can growth be measured?
Weight, height/length (difficult in young children) and head circumference
What are the female features of puberty and when do they happen?
Breast development - 8.5-12.5 years
Pubic hair growth and growth spurt - immediately after breast development
Menarche - 2.5 years after the start of puberty
What are the male features of puberty and when do they happen?
Testicular enlargement - first sign of puberty
Pubic hair growth - between 10 and 14 years of age
Growth spurt - 18 months after testicular enlargement
What are features of puberty that are present in both sexes?
Acne, axillary hair, body odour and mood changes
How can abnormally early or late puberty by assessed?
Bone age measurement from X-ray
Females: pelvic US to assess uterine size and endometrial thickness
How is short stature defined
Height below the second centile or 0.4th centile
How do you measure height velocity and what is abnormal?
Two accurate measurements at least 6 months but preferably a year apart. A height velocity persistently below the 25th centile is abnormal and that child will be short.
How do you calculate a genetic target centile for growth?
The mean of the fathers and mothers height with 7cm added for the mid-parental target of a boy, and 7cm subtracted for a girl
What is the link between IUGR/extreme prematurity and growth?
1/3 of children born with severe IUGR or who were born extremely premature remain short. Growth hormone treatment may be indicated
What is constitutional delay of growth and puberty?
These children have delayed puberty, which is often familial, usually having occurred in the parent of the same sex
Is constitutional delay of growth and puberty more common in males or females?
Males
Which endocrine conditions can cause short stature?
Hypothyroidism, GH deficiency, IGF-1 deficiency and steroid excess are uncommon causes of short stature. They are associated with overweight children
Can you treat short stature due to hypothyroidism?
Yes, catch up growth rapidly occurs but often with a rapid entry into puberty that can limit final height