Growth in childhood Flashcards
How do we measure growth in children?
Centile charts.
What are centile charts? What do centile charts tell us?
There are centile charts for a range of growth measurements – head circumference, height, weight, BMI and more. They are based on surveys of a large number of children in the UK. Centile charts are not a ‘normal range’ – they are just a way of looking at where height is compared to others.
What is the importance in measuring head circumference?
Measures brain development and growth. You do not measure once the bones have fused.
How do you measure a child and plot on a centile chart?
An accurate measurement is obtained if the equipment is accurate, shoes are taken off and clothes off if a child is being weighed. The values are plotted onto the following chart:
What two ways is height in children assessed? !
We use centile charts to assess CUMULATIVE HEIGHT – how tall the child is now, with measurements recorded from growth since conception. HEIGHT VELOCITY is also measured – it is a measure of how fast a child is growing in cm per year and usually calculated over a whole year (most short children are growing at a completely normal speed).
What influences are there on growth in childhood? (x4)
□ Events before birth such as poor foetal growth, low birth weight and prematurity. □ Medical issues in childhood such as malnutrition, chronic disease, endocrine problems including growth hormone deficiency. □ Genetic factors including the height of the family and any inherited disorders of growth. □ Randomness: not every child of the same parents will be the same adult height. There are multiple genes which determine adult height, and these are randomly distributed at conception.
What does normal growth look like on a centile chart look like – from birth to puberty? !
□ The fastest phase of growth after birth is in the FIRST 2 YEARS: children can move up and down through the centiles at this phase of growth. □ By 2 to 3 years of age, most children will stay in the same centile position and then continue on this centile position through childhood. Normal children grow fast enough to keep on the same centile and movement up or down is unusual. □ There is a phase of fast growth at puberty – the pubertal growth spurt. The timing of this depends on the age at which the child enters puberty. □ The skeleton matures as the child grows and the epiphyses fuse at the end of puberty, and growth stops.
How is growth in childhood hormonally controlled?
□ GROWTH HORMONE is the most important hormonal factor in growth.
□ Growth hormone secretion is controlled by the hypothalamus, which secretes GROWTH HORMONE RELEASING HORMONE (GHRH) which secretion and SOMATOSTATIN which suppresses secretion. GHRH secretion is stimulated by exercise, nutrition and sleep.
□ Growth hormone is released by the pituitary as PULSES – most of which occur overnight.
□ Growth hormone has some growth effect itself and also stimulates the release of INSULIN-LIKE GROWTH FACTOR I (IGF1).
□ IGF1 is produced mainly in the liver, growth plates, as well as in target tissues as a paracrine/autocrine function. It circulates bound to a number of binding proteins and stimulates growth in all the tissues of the body.
What causes children to grow slower than normal? (x7)
□ Poor nutrition. □ Chronic disease such as asthma, sickle cell, juvenile arthritis, IBD, CF and more. □ Endocrine diseases such as GH deficiency, steroid excess and thyroid hormone deficiency (hypothyroidism). □ Genetic disorders affecting bone growth (e.g. achondroplasia (genetic condition that results in dwarfism), Turner syndrome, Down’s syndrome). □ Psychological stress and neglect. □ Pubertal and growth delay. □ IUGR/SGA.
What cause tall stature in children? (x4)
□ This is not usually a concern. Most tall children have normal growth pattern. Causes to consider are: □ Tall parents. □ Syndromes of overgrowth including Marfan syndrome and Soto syndrome. □ GH excess from a pituitary tumour. □ In precocious puberty, the pubertal growth spurt occurs very early and so children will present with tall stature. However, growth stops early so they can be short adults.
What is obesity defined as?
For adults, obesity is defined is BMI is over 30 kg/m2. Children have lower BMI than adults, and this changes with age, so these figures do not apply, and obesity is assessed on the BMI centile position. See photo.
Why is childhood obesity a concern? (x4)
□ Emotional and behavioural issues from stigmatism, bullying and low self-esteem. □ School absence. □ High cholesterol, high blood pressure, pre-diabetes, orthopaedic problems and increased risk of cancers. □ Obesity predisposes children to obesity in adulthood.
What are the main factors linked to obesity in childhood? (x2)
□ Single gene mutations affecting hormones in the hypothalamus which regulate appetite (including leptin). This leads to excessive appetite and severe obesity. Monogenic conditions include: Leptin deficiency, leptin receptor deficiency, POMC deficiency, PC-1 deficiency and more. □ Polygenic inheritance of multiple genes can lead to obesity. In the population there are some gene variants (for example the FTO gene) which can affect eating behaviour and appetite and make an individual more likely to eat in a way that makes them gain weight.
