The Short Child
Is he normal?
Parents and children, especially teenagers, often worry when they notice that they are not as tall as many of their peers and classmates of the same age.
While there are many medical conditions that can cause children to be short, or have short stature, most children who are short are normal.
This is one time when teens can blame their parents, or at least their genes, for something. Most children are short because they have short parents. Genetics plays a very big role in how tall a person will be.
Parents often ask if their doctor can figure out how tall their children will be. There is a simple formula which will calculate a child's target height or their genetic potential for growth using parental heights. This is important to figure out, because if a child is much below his genetic potential then that may be a sign of a problem.
Children in early childhood usually grow at a rate of about 2 - 2 1/2 inches/year, up until they begin puberty, when their growth will slow to about 1 1/2 inches/year. There is an acceleration in growth as they hit their peak growth velocity in puberty, to about 3 - 3 1/2 inches/year for girls and 4 inches/year for boys. Growth then slows again in girls to about 2 1/2 - 3 inches/year after menarche (the first period) until they reach their adult height. Boys and girls usually continue to grow until they are 14-16 years old, but this depends on when they started puberty. Remember that girls reach their pubertal growth spurt about two years earlier than boys, so in early adolescence, many girls are taller than boys.
When evaluating children who are short, more important than where they are on a growth chart is how they have been growing. To look at this pattern of growth, or a child's height velocity, you usually have to look at several years of growth. Children who are growing normally should follow their growth curve fairly closely, so even if they are at the 5th or 3rd percentile, if that is where they have always been, then they are probably growing normally. If your child is crossing percentiles or lines on the growth curve, then there may be a medical problem causing him to be short. Keep in mind that children may normally cross percentiles in the first few years of life and this is actually a common finding in children with familial short stature or a consititutional growth delay.
Other red flags that may indicate a growth problem include having a chronic medical condition or other symptoms, such as vomiting, diarrhea, fever, weight loss, poor appetite, poor nutrition, headaches, delayed puberty, having disproportionate short stature, which can be a sign of a chromosomal disorder, or being short and overweight, which can indicate an endocrine or hormonal problem.
The most important part of an evaluation of children with short stature is reviewing their growth records. If you have had more than one Pediatrician, then it is a good idea to get all of your children's old records. If they are short, but growing normally, then no further testing may be required. Your doctor may decide to just observe your children's growth over the next 3-6 months to make sure that they continues to grow normally.
Testing is sometimes required, either to rule out a medical condition causing short stature or to reassure your child or yourself that he is growing normally. One of the most important tests is a bone age, which is the chronological age of your child's bones and is determined by taking an xray of his left wrist and hand. If your child's bone age is much less than his chronological or real age, then there is probably still room for his bones to grow after the age that you would normally expect him to already stop growing. Girls usually continue to grow until a bone age of about 14 years, and boys stop growing after a bone age of 16 years (with a peak growth rate at a bone age of 14 years). Having a delayed or advanced bone age can also be a sign of a problem that needs further evaluation.
Other tests can include blood tests to check for hypothyroidism (T4 and TSH), growth hormone levels (usually by checking IGF-1 and IGF BP3), complete blood counts (CBC to check for anemia), blood chemistries (which can include a SMA 20 to check for kidney and liver disease), urinalysis, and sometimes a karyotype to look for chromosomal abnormalities (especially in girls who are suspected of having Turner syndrome).
One of the most common normal reasons for your child to be short is having familial short stature, in which a child's parents and other family members are also short. These children usually grow at a normal rate, although they are short, and they follow a growth curve that may be below, but runs parallel to the normal growth curves. Although testing is not routinely required, if a bone age is done, it would be normal and not delayed.
Although there are a lot of normal reasons for your child to be short, there are also some serious conditions that require treatment. Children with these conditions are short, but are also not growing normally, are not following a growth curve and often cross percentiles downward. One of these conditions, and the one which parents are usually worried about, is growth hormone deficiency. Growth hormone is required for normal growth, and children with growth hormone deficiency are short, often look younger than their chronological age, and they can be chubby. While they will usually have a delay in their bone age, like children with a constitutional delay, children with growth hormone deficiency will have a slow rate of growth and they will have a growth curve that falls away from the the normal growth curves. Testing that can be done if your Pediatrician suspects your child has growth hormone deficiency include checking the levels of IGF-1 and IGF BP3, which will be low. A growth hormone stimulation test may also be done by an endocrinologist. Treatments for growth hormone deficiency include growth hormone replacement. Other conditions for which growth hormone is currently being successfully used include Turner syndrome, chronic renal failure and Prader-Willi syndrome. Growth hormone defiency may be congenital (a child is born with it), or it may be acquired later in life from head injury or a brain tumor or mass.
Growth hormone therapy has also recently been approved for the long-term treatment of children with idiopathic (of unknown origin) short stature, also called non-growth hormone deficient short stature, if they are more than 2.25 SD below the mean for age and sex, or the shortest 1.2% of children.
Keeping good records of your children's height and weight can make it a lot easier to evaluate a child with short stature. Be sure to go to your regular well child visits with your Pediatrician, and even at a sick visit, ask them to measure your child's height if it hasn't been done recently. While most Pediatricians can begin the initial evaluation of a short child, if additional testing is required, or you or your child need reassurance, then a visit to a Pediatric Endocrinologist can be helpful.