Childhood growth Flashcards
Why do we measure growth
poor growth in infancy is associated with high childhood morbidity and mortality.
Growth is the best indicator of health
How do we measure height
Measuring height: lying flat for babies, and standing flat against wall for those old enough to stand
Summarise growth
By the time of birth the fetus has grown from the size of a single fertilized egg to (if the baby is born at term) an average of 50cm long and 3.3kg weight. Growth in height is completed over the next 12-16 years. The pattern of growth in normal children is very consistent and centile charts are a way of checking that growth is normal. A number of factors can adversely affect growth in height- nutrition, hormone problems, genetic diseases.
What is the red book
Centile charts are a way of looking at this range of height and checking that growth patterns are normal. Every child has a handheld record which includes their growth charts- the “Red book”.
Essentially, what is a centile chart
Centile charts are a way of expressing variation within the population: Head circumference Weight Height/Length Leg length BMI Growth Velocity Specialist Charts.
how are centile charts made
Development: sample of population taken and height recorded and plotted on a normal distribution
Summarise what a centile chart tells you
There are centile charts for a range of growth measurements- height, weight, head circumference and BMI are the commonest
They are based on surveys of large numbers of children- in the UK we use both UK population based charts and ones from the WHO which look at an international population.
To use a centile chart you plot the age (x axis) against height (y axis). 50% of children will be shorter than the 50th centile, 25% shorter than the 25th centile, and so on.
Centile charts are not a ”normal range”, they are just a way of looking at where height is compared to others
There are centile charts for girls and boys
Describe the importance of getting an accurate measurement of growth and height
Getting an accurate height and weight is important in assessing growth.
The equipment should be accurate and maintained properly
Position the child properly to get an accurate height (read the instructions on the growth chart)
Make sure you get rid of things which interfere with measuring- shoes off, hair out of the way, clothes off to weigh.
Calculate the age and plot correctly on the chart.
How do we look at height and growth
The centile charts we use are for cumulative height – how tall the child is now, (the total of all the growth they have done up to now, from conception).
Height velocity is how fast a child is growing in cm per year, usually this is calculated over a whole year. Most short children are growing at a completely normal speed.
Other useful information when assessing growth is the height of family members- parents and siblings. Ideally measure them yourself because people can be very inaccurate in assessing their own height.
Summarise how we interpret centile charts
Many parents (and quite a few health professionals) find it very hard to accept that 50% of the population is below average.
For most children on the bottom centile for height there is nothing at all wrong with them (and your medical assessment is to look at this), and there is no reason that they should be higher up on the centiles.
Children who are referred to hospital for height concerns are a very selected (and unrepresentative) group. Many short children are never seen in a hospital clinic.
Pattern of growth important- if they fall of the centile- then it indicates a growth problem- nutrition etc
Why do we measure head circumference
Marker of brain development
Fontanelles exist in baby to allow growth of brain- head circumference will increase as brain develops and the bones of the skull will eventually fuse
Fall of centile- insult, abnormality in brain developmen
Increase in centile- hydrocephalus.
How do we measure heigh velocity
Height now - height last visit / age now- age last visist
Expressed in cm/yr
Interval approx 6 months.
Describe the trends in growth velocity
Trends: height velocity highest at birth, then decreases sharply by 2 years old, with a spike at puberty (girls at beginning, boys at end) - synergy between sex steroids and GH produces pubertal spike
Summarise the endocrine control of growth
GH-IGF-1 axis regulator of human linear growth
GH single chain polypeptide
Somatotroph cells of anterior pituitary
Pulsatile secretion- why one off measurement pointless
Influenced by nutrition, sleep, exercise and stress.
Describe the endocrine control of growth
Growth hormone (GH) is the most important hormonal factor in growth.
GH secretion is controlled by the hypothalamus, which secretes growth hormone releasing hormone (GHRH) which stimulates secretion and somatostatin which suppresses secretion. GH is released by the pituitary as pulses most of which occur overnight.
GH has some growth effect itself and also stimulates the release of IGF1 (insulin like growth factor !).
IGF 1 circulates bound to a number of binding proteins and stimulates growth in all the tissues of the body
IGF-1 made in liver, bones (growth plates) and muscle.
Describe the different phases of growth
Antenatal: most rapid phase of growth - maternal/placental health key factor
Infancy: rapid growth (23-25cm) in first year, but dependent on nutrition, with GH not causing growth until months 9-12
Childhood: growth rates in males and females similar, with less dependence on nutrition and growth driven by GH/IGF-1. Post infancy to adolescence. Nutrition has less impact- but malnutrition can inhibit growth.
Puberty- sex steroids and GH stimulate the pubertal growth spurt- occurs at the start of puberty in females, at the end for males.
What is meant by bone age
Bone age
Membrane- skull and clavicle
REst- ossifying of cartillage- IGF-1 makes osteoblasts divide and produce bone- growth plates fuse once bone has fully grown.
Describe the cessation of growing
The bones mature and epiphyses fuse at the end of puberty
The final part of growth occurs in the spine and the final epiphyses to fuse are the pelvis.
What questions can we ask
Is a child too short or tall for their age- is this a problem,
Has puberty started and is it progressing normally
Is growth normal for the stage of puberty
Is this child overweight or obese
What can we learn
Centiles are not a normal range
You can be taller or shorter than the cantle lines and still be completely normal and healthy
Most children set out on a centile and by about 2 years and grow on the same centile during childhood.
Patten of growth is more important than position on the gentiles.
Most very tall people or very short people are healthy and grow in a normal pattern
A child who falls significantly in centile position is not growing normally, whatever their height.
Outline the different causes of short stature
Genetic - achondroplasia
Pubertal/growth delay
IUGR/SGA - born small- 85% catch up
Dysmorphic syndromes - Turner’s, Down’s- tend to be shorter
Endocrine disorders (hypothyroid, GH deficiency or steroid excess)
Chronic paediatric disease (chronic inflammation e.g. CF, renal disease, sickle cell)
Psychosocial depravation (depressed GH function)
When does puberty start
Males- 9- 13
Females - 8- 13
Describe some other causes of short stature
Normal growth pattern
Most short children have a normal growth pattern and do not have any medical problems
They are usually the children of small parents
Not all children with IUGR catch up completely. Growth will be normal in childhood bu they have lost ‘some’ height in the antenatal period.
If you see a small patient what should you look at
Birth history and weight
Parental heights
Medical History
Previous measurements
Calculate mid parental centile
The mid parental height is calculated in males, by adding 7cm to the mean of parental heights; in females by subtracting 7cm. This gives the height expected at 18 years for the child, and this can be plotted on the percentile chart to predict the child’s height at the appropriate age. This can normally vary by two standard deviations, or 5cm each way (1).
This measurement aids distinction between genetic and constitutional growth disturbances.
Describe the endocrine causes of short stature
Hypothyroidism
GH deficiency
Steroid excess
If a child is not parallel to the parental heights, what investigations should be carried out
FBC- rule out infection CRP- rule out infection Serum iron- see if deficient Liver and Kidney function Thyroid funciton- hypothyroidism results in short height\ Coeliac screen- dodgy poos, sore stomach- inflammation reduces growth, that it- gluten free diet- grow normally IGF-1 Bone age -see bone maturity MRI pituitary pituitary function test
Describe the genetic syndromes that can lead to short stature
Turner syndrome XO
Down syndrome T21
Skeletal dysplasias- something wrong which look after bones
Describe how significant illness can affect growth
Because of inflammation, poor nutrition and the effects of drugs such as steroids
IGF-1 needs to bind to receptor and trigger intracellular cascades, inflammation does the same and essentially exhausts mediators and receptors.
What happens to patient’s with Turner’s
We give GH induce puberty- they have streaked ovaries and so can’t go into puberty themselves
What investigations should you carry out in patients with achondroplasia
Measure sub-ischial leg length
Measure total height
Then sit the patient down- measure form bum to head
Take values away to get sub-ischial height
Sitting height- normal
leg length- short.
Describe the chronic paediatric diseases that can stunt growth
Asthma SCD Juvenila chronic arthritis IBD- Chrons and coeliac Cystic Fibrosis Renal Failure Congenital Heart Disease
Describe the causes of tall stature
Tall parents
Early puberty (5/60) - intervene- prevent psychological effects
Marfan’s syndrome
GH excess- growing and bones aren’t fuses- so grow taller- cerebral gigantism- not common
Sotos syndrome (cerebral gigantism) is a rare genetic disorder caused by mutation in the NSD1 gene on chromosome 5. It is characterized by excessive physical growth during the first few years of life.
Summarise the causes of tall stature
Tall stature is a very unusual concern. Most tall children have a normal growth pattern and do not have anything wrong with them. Causes to consider are:
Syndromes of overgrowth including Marfan syndrome and Soto syndrome
GH excess from a pituitary tumour. This is very rare indeed, most of the “tallest men and women in the world” have had this diagnosis
In precocious puberty the pubertal growth spurt occurs very early and so children with this can present with tall stature. However growth stops early as well so they can then be short as adult
Describe the epidemiology of obesity
2/3rd of adults
1/4 of 2-10 year olds
1/3rd 11-15 year old
Overweight or obese
Most adults and children are severely obese- predicted to reach 70% by 2034.
High BMI- costly to health and social care, has wider economic and societal impacts- as these people get sick.
Most obese children will become obese adults.
What is the barker hypothesis
The Barker hypothesis proposed that adverse nutrition in early life, including prenatally as measured by birth weight, increased susceptibility to the metabolic syndrome which includes obesity, diabetes, insulin insensitivity, hypertension, and hyperlipidemia and complications that include coronary heart disease and stroke. Periods of rapid postnatal growth associated with high-energy intake seem to be risk factors, along with a high-energy western diet.
Related to thrifty gene hypothesis etc
Describe the consequences of unhealthy weight
UW- higher risk of death
Normal weight -low risk of death
Risk increases again as you become more obese.
Describe how obesity harms children and young adults
Emotional and behvaiour - stigmatism, bullying, low self-esteem- don’t go to school- don’t thrive
School absence
High cholesterol, HBP, pre-diabetes, bone and joint problems, breathing difficulties.
Increased risk of becoming overweight adults, risk of ill-health and premature death in adult life.
Describe the complications of obesity and associated features
T2DM- bad in children- more likely to get microvascular and macrovascular complications- more aggressive in T2DM Orthopaedic problems PCOS CVD risk Psychological problems Cancer Respiratory problems
Describe the mapping of BMI in children
Centile- different to that of adults.
Describe the prevalence of excess weight in children
20% in reception
33% in year 6
What is closely related to obesity
Deprivation
Less access to healthy food and exercise
Describe some syndromes associated with obesity
Tall, obese child- likely to be overfed
Short, obese child- likely to have a syndrome:
Cushing’s- lots of steroids
Prader-Willi- uniparental disomy- learning difficulties, food-seeking behaviour, almond eyes, fat pads on hands, underdeveloped genitalia.
Laurence-Moon-Biedl (Bardet-Biedl) syndrome- polydactyly- pigmentation in eye- learning difficulties
Summarise the genetics of weight
Polygenic inheritance Highly heritable trait (40-70%) Monogenic obesity syndrome - rare- be alarmed of obese child <5 Leptin deficiency Leptin receptor deficiency POMC deficiency PC1 deficiecny MC4R- increased muscle bulk and fat.
Describe how many families’ are considered with their child’s height
Many families who come with concerns about their child’s growth are also looking for a treatment that will make them taller. For almost all of these families not only is their child completely healthy and normal, we cannot do anything that will change their adult height.
Children with confirmed GH deficiency will get a significant improvement in their adult height with treatment, and there are a number of other disorders of growth where there is some benefit from treatment.
There have been multiple trials of GH treatment in children who do not have anything wrong with them but are just short (“short normal children”). Treatment is not given to these children because the tiny improvement in height seen is not worth the time, effort and expense of treatment.
Deifne obesity
For adults BMI of over 25 kg/m2 is overweight and over 30 kg/m2 is obese. 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.
Describe the worldwide obesity factors
Obesity is getting more common although there are still a lot of adults and children in the world who are undernourished.
However looking at the statistics tells us that the situation is quite complicated:
Rates of obesity and overweight have increased but may not continue to go up at the same rate for the future
There are some nations who have a much higher rate of obesity than others. There are some cultures where overweight has traditionally been seen as a desirable feature indicating wealth and high status. In some areas of the world obesity is a feature of poverty and in others associated with affluence.
Some ethnic groups have less “tolerance” of obesity and are more likely to get complications like type 2 diabetes at a lower BMI
Why does obesity happen
Obviously this is the balance of energy taken in as food versus energy expenditure.
Hunger is regulated by the hypothalamus and there are a number of factors (including leptin) which regulate this. There are a very small number of individuals with single gene mutations affecting one of these hormones which results in an excessive appetite and can lead to severe 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.
Summarise how children grow
The fastest phase of growth after birth is in the first 2 years of life. Children can move up and down through the centiles at this phase of growth.
Most children w ill move to a centile position by 2 to 3 years of age 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, the epiphyses fuse at the end of puberty, and growth stops.
Summarise what can influence normal growth
If you plot a child on a centile chart, their current height position on the centile looks at all the growth they have done from conception up to this point. This can be influenced by:
Events before birth- poor fetal growth, low birth weight, prematurity
Medical issues in childhood- malnutrition, chronic disease, endocrine problems including growth hormone deficiency
Genetic factors- 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, and tall parents can occasionally have a short child. There are multiple genes which determine adult height, and these are randomly distributed at conception.
