Constitutional growth delay

Definitions & Key takeaways

Constitutional growth delay (CGD) is a condition in which some children grow slowly during early childhood and puberty compared to their peers. CGD is the most common cause of short stature in children and pubertal delay in adolescents. It is considered a normal variation to growth because individuals with constitutional growth delay usually end up achieving normal adult heights by adulthood.

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Introduction0:00–0:28

Constitutional growth delay is a normal variation of development where there’s a temporary delay in growth that occurs during early childhood and puberty.
You can think of it as a slowed rate of maturation, which happens normally in some people. It’s the most common cause of short stature and pubertal delay in children and adolescents, but by adulthood, people with constitutional growth delay generally end up with normal adult heights.
Generally speaking, there are two hormonal systems that control growth - the growth hormone axis and the hypothalamic-pituitary-gonadal axis.

Physiology0:28–3:53

The growth hormone axis starts with the hypothalamus which is at the base of the brain. The hypothalamus secretes growth hormone-releasing hormone and that stimulates the anterior pituitary gland to produce growth hormone.
Now, growth hormone affects lots of tissues - in particular it makes the body retains nitrogen leading to more muscle growth, and osteoblasts get stimulated which causes the bones to thicken.
Growth hormone also stimulates certain tissues like the liver, skeletal muscles, bones, and kidneys to produce somatomedin C, also called insulin-like growth factor 1.
Insulin-like growth factor 1 promotes cellular metabolism, prevents cell death, and helps cell divide and differentiate throughout the body.
It’s also the key hormone that stimulates the growth in length of long bones. Now, sexual maturation is under the control of the hypothalamic-pituitary-gonadal axis.
This axis also starts with the hypothalamus which releases Gonadotropin-releasing hormone, or GnRH which stimulates the anterior pituitary to produce the gonadotropin hormones: luteinizing hormone, or LH, and follicle-stimulating hormone, or FSH.
LH and FSH stimulate the gonads to produce sex specific hormones - which are estrogen and progesterone in females, and testosterone in males.
Now, the amount of hormone that gets produced by this axis varies over a person’s lifetime, and that affects the development of the sex organs, as well as the appearance of secondary sexual characteristics.
During puberty, there’s increased GnRH production and increased levels of FSH and LH, and that triggers the onset of sexual maturity.
The stages of sexual maturity that a person goes through are referred to as the Tanner scale. The Tanner scale centers on two, independent criteria: the appearance of pubic hair in both sexes; and the increase in testicular volume and penile size and length in males, and breast development in females.
There are five stages: In stage 1, the prepubertal stage, no pubic hair is present in either sex. Males have a small penis and testes.
Females have a flat-chest. In stage 2, pubic hair appears and there’s a measurable enlargement of the testes; and breast buds appear.
In stage 3, pubic hair becomes coarser; the penis begins to enlarge in both size and length; and breast mounds form. In stage 4, pubic hair begins to cover the pubic area; the penis begins to widen; and breast enlargement continues to form something called a “mound-on-mound” contour.
In stage 5, pubic hair extends to the inner thigh; the penis and testes have enlarged to adult size; and the breast takes on an adult contour.

Pathology3:53–5:34

Constitutional growth delay is not a disorder but a normal variation in the rate of growth. Growth charts are often used to track the development of children, and they usually have age on the X, or horizontal axis and head circumference, weight, or height on the Y, or vertical axis.
The children typically have normal height and weight at birth but during the first few years of life their growth rate declines.
Children with constitutional growth delay may fall to right around the 2nd percentile, but their growth rate picks up again and matches that of their peers by age four.
At that point, their growth rate is parallel to other children, meaning they are growing similar number of centimeters or inches per year, but their overall height still lags behind other children their age.
When other children hit puberty, children with constitutional growth delay are still a bit behind in terms of growth and sexual development.
But they typically have a growth spurt later than normal and use that to catch up with their peers both in terms of height and sexual development, ultimately reaching a normal adult height.
An analogy is having two kids in a race. One child starts the race normally but the other child put the wrong shoe on the wrong foot and can only hobble along.
The first kid pulls ahead and the other kid fixes his shoes and then runs at the same speed as the first kid. The kid that started normally will finish first and in this case reach adult height first.
But the other kid will also finish the race, just a few minutes later because of that initial delay in fixing his shoes.
The cause of constitutional growth delay is not well understood. It may be due to a transient growth hormone deficiency or to a pituitary gland that doesn’t start producing hormones on time - like snoozing through an alarm.
There does seem to be an inherited element, meaning that individuals with constitutional growth delay are more likely to have children with a constitutional growth delay as well.

Symptoms5:34–5:59

Aside from a delay in growth and a delay in developing sexual characteristics, constitutional growth delay doesn’t come along with any other symptoms, and people usually have a normal adult height.
Unfortunately, some individuals can feel a lot of psychological stress from a constitutional growth delay, because they may feel like they don’t fit in with their peers, and it can trigger feelings of depression and anxiety.

Diagnosis5:59–7:06

Constitutional growth delay is the most common cause of short stature which is having a height that’s below the 2.3 percentile.
It’s also helpful to get a bone age, which is the degree of maturation of a child's bones, and it’s usually determined based on an x-ray of the left hand.
In constitutional growth delay the bone age is at least a year less than a child’s actual age. Since constitutional growth delay is a normal variation of growth, it’s critical to distinguish it from possible causes for the growth problems.
Constitutional growth delay can be distinguished from hypothyroidism because there are normal levels of thyroid hormone.
It can be distinguished from Cushing syndrome because there should be a normal 24 hour urine cortisol level. Finally, if there’s a tumor compressing the pituitary gland causing growth hormone suppression could be diagnosed by a stimulated growth hormone test where synthetic growth hormone release hormone is given to a person to see if growth hormone is released.

Treatment7:06–7:29

In most cases of constitutional growth delay, the most important thing is to reassure individuals that the delay is temporary and that they will still reach their adult height and sexual development - a bit later than their peers.
In rare cases, a short course of sex-steroids can be used to speed up sexual development. Alright, as a quick recap constitutional growth delay causes an overall delay in growth during childhood and pubertal development, but ultimately results in a normal adult height.

Review7:29–7:51

The main problem with constitutional growth delay is its association with psychological distress, which can be treated with a short course of sex-steroids.