Endocrinology and Diabetes
Childhood Growth Sal talks with Dr. Laura Bachrach about childhood growth
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- I'm here with Dr. Laura Bachrack at Stanford Medical School
- and what are we going to talk about?
- We are going to talk about normal and abnormal growth in children
- Fascinating...so, this is an important concern...
- Parents really worry if their child is growing normally
- and physicians worry about this too because
- the change in height is an important barometer
- of how the child is doing overall in terms of health
- Right...so to begin to assess the child's growth pattern
- we have to think about what are the determinants
- of where the child should be on the growth curve
- Right...the number one most important determinant,
- of course, is genetics. Short parents are more
- likely to have short children and vice versa
- And that's also true even when the child is young
- if...like...big, cause sometimes I've seen in the opposite
- so, you know....people who are petite have large children
- and all the rest but it is true even if someone is large or
- someone is large they're more like to have large children
- even in infants and toddlers...
- You have hit upon a really important issue that is
- shown here in the slide.. the size of a baby at birth
- isn't necessarily going to reflect the genetics
- There are babies that are born small because the mother
- didn't have pre-natal care...mother was a smoker...
- other factors that compromised the growth of the child
- and those can be born small for their gestational age.
- During the first two to three years of life, they have
- a chance to catch up on the curve and reach what's
- called their genetic potential. So let's say...
- So, I want to make sure...I have seen these curves before...
- I remember this when I used to visit the Paediatrician
- which I did, may be a little too long, but eh, so
- so this axis right over here is age, in months
- In months...so this is right here at birth. So if a baby
- born at, I don't know, uh, this is the weight right over here
- So if the baby are born at 5 pounds,
- is this in pounds, this is in kilograms. So 5 pounds is
- right over here. So this would be a baby born at 5 pounds.
- And I'm talking more here during this growth lecture about
- the height or the length of the baby
- throughout childhood, but let say
- the baby were born light in weight and short in length
- So maybe 18 inches here would be a short length.
- And let's say that that baby were small because
- his mother had issues during pregnancy.
- Is it always the case that the baby would be small because of issues or i mean...
- No...the bottom line is the genetics
- plays less of a part in the size of the baby at birth
- and it will later on in childhood.
- So it comes back to your point. You'll meet parents whose baby seemed
- a bit larger or smaller than they are.
- But by age 3, the child should be...
- Hold on 1 second, let me just
- close this...OK.
- By age 3, the child should be in his or her genetic group if you will.
- So, there can be movement on the growth curve in the first 2 to 3 years
- of life. There can be catch up growth where the child who were small
- let's say moves from below the curve up to the 50%
- by age 24 months. And you could have the convert.
- Where you have a very big baby, let's say the mother had uncontrolled diabetes
- and the baby was born very large, that baby can have catch down growth
- to the 50%. By the age of 3, certainly movement across percentile
- is considered to be abnormal and warrants an investigation.
- So you really can predict someones even adult height based on where they are at 3?
- The general rule of thumb is that by the age of 2 and a half to 3 the child is in their genetic
- growth. Really? Mhmmm... Wow..I didn't realize that that quickly you can kinda..
- So if a child in age of 3 or 4 is in the 25% of height, it is unlikely
- that they are gonna be in the NBA.
- In general that's true there's a few exception there are late group of bloomers
- what we call a constitutional delay of growth
- but the general rule would be what percentile you are by the age of 2 or 3
- is pretty much where you're gonna track if all things are going normally.
- Wow..I never realize that's ahh...that's ahhh..
- In genetics, it's an important determinant as they said. we can actually do a calculation
- of where we think the child should end up the so called mid-parental height
- I wish we're gonna talk about it later.
- So, genetics is a critical factor but whether or not you reach your genetic potential
- means that the cards have to be lined up appropriately.
- So the cards that are important for achieving your genetic potentials
- first of all, number one, normal amounts of hormones that are important for growing.
- And those are thyroid and growth hormone to a large extent.
- The second factor of course is adequate nutrition and we think worldwide of children
- who are under nourished who don't look anywhere near their age in terms of height
- because they're so under nourished.
- And you see the reverse of that, I mean I was born here and my parents were the 1st or 2nd generation..
- we see that people in my generation are much taller that their parents because their parents
- were probably malnourished in some way.
- Certainly there can be a secular trend where the children get taller than their parents
- if the children have a different environment. The other thing that we notice about
- nutrition in our country is the over nutrition of our children and what happens
- with obesity is that children may grow faster, in terms of weight and height for their age..
- they don't end up taller in the long run but they move ahead more quickly through the maturation process
- I see...like they accelerate. Exactly.
- I never realized that. That's fascinating.
- And then we think about psycho social factors, there literally a situation where
- infants can be deprived of parental love and support and you can see
- some dwarfing there. In a teenager we see problems with eating disorder
- that's a cross between nutrition and a psychological problem.
- It a psycho social factors.
- So it's been seen that it's a noticeable changes in physical development based on
- attention in love and....
- Yes, there's actually a syndrome called Psycho Social Dwarfism
- where you actually see them slow down in growing without adequate interpersonal support.
- So, the issue is when do you need to worry about a child's growth pattern.
- In order to interpret that you really have to understand about the variability in growth.
- In the first 2 to 3 years of life children grow much more quickly than they will later on..
- By the age of three, until they hit puberty, children should grow 2 inches a year.
- This is out of the toddler hood until they hit puberty.
- Wow, so this is like the tree of puberty. Exactly, exactly.
- But when kids will hit puberty is going to be very long...
- and so that's an issue. If the children are growing at a normal rate
- it's not necessary to memorize the inches per year
- Children will track along the growth curve and if we could turn to the next
- slide or graph. This is the graph that we use for older children.
- After the age of 2 up until they're 18. This is the curve that we use.
- Now, beyond the age of 2, I told it is not normal for the children to
- necessarily cross percentiles. So if for example you have a child
- who is tracking along the 5th percentile every year growing their 2 inches per year...
- They're moving along steadily, steadily, steadily...
- that child has a more reassuring growth curve than one for example
- who as a 5 year old had been on the top of the curve
- and then the next year is on the 75th moving down the line
- and the year after is on the 50th percentile.
- Now that point in time the child has theoretically a normal height
- because its within the curve, but there's something very abnormal
- about that rate of growing and that's the child is more worrisome than the shorter child.
- I see...fascinating.
- So bottom line when a child would come in to present to me because of the concern
- about growing, I first of all try to decide if they're short and if they're growing normally.
- And those are 2 different questions.
- The 1st question is are they short? And are they short can be defined by looking
- at these curves. These are curves representing the spectrum of normal height
- for healthy American youth. And they go from the 5th to the 95th percentile.
- So you can compare a child to the population as a whole
- but I also like to calculate what we call the mid-parental height.
- This is where we take into account the heights of the parents.
- Because that's the most important determinant.
- So how we calculate that is as follows.
- We take the height of mom and dad and average them.
- OK, let's do that.
- So, I'm 5"9 if I'm wearing decent shoes.
- And how tall is the mother of your children?
- She's 5"6.
- And are we trying to calculate your son or your daughter?
- Let's do my son since he's little older, so he is plus 66 inches.
- So we'd take the mid-point of that and we're gonna add 2 and a half inches.
- OK, so that gets us exactly 70 inches.
- Right, so that's the height prediction for your son.
- Oh, very good.
- Plus or minus...4 inches.
- Oh, plus or minus 4 inches, that's a big difference.
- It's a big difference but that's the nature of human variability.
- OK, if these were your daughter, we would take the 67.5 inches and subtract 2 and a half inches.
- Let's do that.
- OK, so she would get 65...plus or minus 4 inches.
- So that's something we do. We then calculate, in fact let's plot that
- right on the curve, this is the boy's curve. So let's plot the 70 inches.
- 70 inches is right over here, OK.
- And then the range of 74 to 66.
- Pretty broad range. OK, but if we had a child who is growing well below the curve
- and we thought that mid-point she'd be about the 50th percentile,
- that child would be short for the family.
- So we always like to take the family's height into account.
- So, number 1 question is the child short?
- It will depend on what the height prediction is.
- I see. So if my son was tracking down here at the 5%...that would be concerning.
- Even if he's growing the 2 inches every year, it would still be concerning?
- Well, it would raise some questions in our mind.
- But more important factor is not just where they are on the curve at the moment,
- but are they growing at the normal rate.
- And the child who is not growing at the normal rate raise more red flags
- than the child who is trotting up the curve.
- Fascinating, it's interesting. Wow!
- So that's the issue and that's what we approach every day
- we want to look into the various causes, potentially for a growth slowdown
- we want to adjust treatment to the specific ideology
- And ideology means....?
- Well for example, if the child has a deficiency of thyroid hormone, we'd want
- to give the thyroid hormone back.
- So ideology is like the cause of the...right, right, right..
- So if the child isn't growing because he has a nutritional problem like Celiac disease,
- we want to put him on a special diet to address that issue.
- Some parents think, well, what we wanna do..my child is healthy and normal and growing normally
- but I wanna give him growth hormone, that becomes a topic in itself.
- Well, thank you for this. This is super informative.
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