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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.