Constitutional Growth Delay / Idiopathic Short Stature – Our Experience

E was born at the 50% centile and followed the 50% growth curve for her first year.  At that point, she started slowly dropping in her growth velocity.  By 18-24 months she had dropped to the 5th percentile; she continued dropping until she fell below the 1% line.  Since age 3, E has tracked steadily under the 1% for height.  Her weight has varied from about 5-20%.

When your child drops more than 2 curve lines on the growth charts, they are flagged for “failure to thrive”.  At this point, we were referred to feeding clinics and nutritionist consultations.

At the feeding clinic, an occupational therapist, physical therapist, nutritionist, and psychologist evaluated E while she ate a typical meal.  She was eating independently (since 6 months old – we followed Baby Led Weaning), and they were happy with her interest in food and physical ability to feed herself, chew, and swallow.  At that point the nutritionist gave us suggestions to increase her caloric intake.

From our post on allergies, you will see how that didn’t go so well for us.

At this point, E had some bloodwork done to rule out nutritional deficiencies.  She also had a left hand x-ray to determine bone age.  Both came back within normal limits.

E’s genetic height potential (which you can calculate for your child here) is 5’1″, but her growth curves lead her to being approximately 4’7″.  Concerned about this, I asked for a referral to a pediatric endocrinologist.

In the meantime, E’s x-ray for bone age was repeated, along with bloodwork to rule out celiac disease / gluten intolerance (which, if untreated, can cause growth delay).   Both came back as normal.

We had our consultation with the endocrinologist, who was very helpful.  She suggested that reading bone age is a bit of an “art form”, and that she reads E’s x-rays as being delayed by about 1-1.5 years (1 step on the bone age scale).  The term for this is Constitutional Growth Delay.  The logical explanation for this would be from her malnutrition when we were feeding her excessive dairy calories, which she wasn’t able to digest.  It had taken a good 1.5-2 years to diagnose her dairy, and subsequent soy and egg, allergies.

The endocrinologist explained that if E’s growth was plotted as if she was 1.5 years younger than she is, it neatly follows the 50% curve again.  She is following E yearly, and we will be able to know more the closer she approaches puberty.  Apparently, if this is what she has, she will eventually reach her growth potential (and just be a “late bloomer”).  Otherwise, she may need daily Growth Hormone injections.  So for now, we are just waiting and watching.

UPDATE 2016:  E had another x-ray for bone age, which came back as normal.  This indicates that she does not, in fact, have constitutional growth delay.  She may be on the borderline normal (which is +/- 5″ of calculated genetic potential) or could have idiopathic short stature.  I did ask for her to be tested for Turner Syndrome, as that can also cause short stature and be undetected if it is a mild case.  Her karyotype came back normal.  The endocrinologist is willing to treat her with growth hormone anyways, but estimates that she would only gain 1-2″ total.  It would also be unfunded, so we would have to pay out of pocket approximately $25,000 per year until puberty ended.  For cost/benefit we just can’t justify this!  I did discuss trying it for only one year, as most catch-up growth occurs in the first year.  However, if growth hormone is discontinued before growth potential ends, often what happens is “catch-down growth” – meaning, growth will slow until she is back on the curve her body was trying to grow on.  We will continue to watch and wait for now, and consider 1 year of growth hormone near the end of puberty (when she is 13-14) depending how things are looking at that time.

Wikipedia describes constitutional growth delay as:

Constitutional growth delay (CGD) is a term describing a temporary delay in the skeletal growth and thus height of a child with no other physical abnormalities causing the delay. Short stature may be the result of a growth pattern inherited from a parent (familial) or occur for no apparent reason (idiopathic). Typically at some point during childhood, growth slows down, eventually resuming at a normal rate. CGD is the most common cause of short stature and delayed puberty.

Children with constitutional growth delay (CGD), the most common cause of short stature and pubertal delay in males, typically have slowed linear growth within the first 3 years of life. In this variant of normal growth, linear growth velocity and weight gain slows beginning as young as age 3–6 months, resulting in downward crossing of growth percentiles, which often continues until age 2–3 years. At that time, growth resumes at a normal rate, and these children grow either along the lower growth percentiles or beneath the curve but parallel to it for the remainder of the prepubertal years.

At the expected time of puberty, the height of children with CGD begins to drift further from the growth curve because of delay in the onset of the pubertal growth spurt. Catch-up growth, onset of puberty, and pubertal growth spurt occur later than average, resulting in normal adult stature and sexual development. Although CGD is a variant of normal growth rather than a disorder, delays in growth and sexual development may contribute to psychological difficulties, warranting treatment for some individuals. Recent studies have suggested that referral bias is largely responsible for the impression that normal short stature per se is a cause of psychosocial problems; nonreferred children with short stature do not differ from those with more normal stature in school performance or socialization.

Individuals with constitutional growth delay (CGD) are usually of normal size at birth. Deceleration in both height and weight velocity typically occurs within the first 3–6 months of life. This shift downward is similar to that observed in infants experiencing normal lag-down growth but tends to be more severe and prolonged. Individual variation is substantial; however, most children resume a normal growth velocity by age 2–3 years. During childhood, these individuals grow along or parallel to the lower percentiles of the growth curve.

Skeletal age, which is estimated from radiographic studies of the left hand and wrist, is usually delayed (typically 2-4 y by late childhood) and is most consistent with the child’s height age (age for which a child’s height is at the 50th percentile) rather than the child’s chronologic age. Because the timing of the onset of puberty, pubertal growth spurt, and epiphyseal fusion are determined by a child’s skeletal age (biologic age), children with CGD are often referred to as “late bloomers.”

At the usual age for puberty, these children continue to grow at a prepubertal rate appropriate for their biologic stage of development. Natural slowing of linear growth just before onset of puberty may be exaggerated, emphasizing the difference in size from peers who are accelerating in growth. The timing of the pubertal growth spurt is delayed, and the spurt may be prolonged with a lower peak height velocity. In patients with both CGD and familial short stature, the degree of growth retardation may appear more severe, but the adult height is appropriate for the genetic background.

I strongly believe that in this life, nothing happens by accident or coincidence – things aren’t determined by fate or luck (good or bad).  I believe there is an overarching story – a beautiful picture of love, loss, and redemption – and that there is Someone who cares and is in control.  You are already a part of this story, whether you know or believe it or not.  While the end of the story has already been written, your own part lays open before you for you to choose your ultimate destiny.  Perhaps our coinciding struggles have been finely orchestrated to lead you to this one moment: The Bridge to God.

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“Praise be to the God and Father of our Lord Jesus Christ. The Father of compassion, the God of all comfort, who comforts us in all our troubles so that we can comfort those in any trouble with the comfort we ourselves have received from God. For just as the sufferings of Christ flow into our lives, so also should the comfort of Christ overflow.” (2 Corinthians 1:3-5)

 

2 thoughts on “Constitutional Growth Delay / Idiopathic Short Stature – Our Experience

  1. Laini Southards

    I’m so interested to read this! I found your blog while searching for constitutional growth delay and food allergies, as we have a child with both. I’ve always wondered if there was a connection, although our endocrinologist didn’t seem to think so. It’s neat to find someone (and their child) who seem to have quite a bit in common with us. Best wishes!

    1. Yeah, both the allergist and endocrinologist kind of smiled and nodded at me when I made the suggestion…but I can’t imagine why they wouldn’t be connected! Since protein is essential for growth, and the protein wasn’t being digested, it makes sense to me 😉 Best of luck in your own growth and allergy journey with your child!

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