Growth Hormone Deficiency
What Is Growth Hormone?
Growth hormone (GH) is a substance in the body that helps kids grow and develop. It is made by the pituitary gland, a small gland between the lobes of the brain.
What Is Growth Hormone Deficiency?
GH deficiency happens when the body does not make enough growth hormone to allow a child to grow at a normal pace.
The two kinds of GH deficiency are:
- Congenital GH deficiency. This is the kind that some babies are born with. They also can have deficiencies of other pituitary hormones. Even though they're born with the condition, some babies look like they're growing normally until they're about 6–12 months old.
- Acquired GH deficiency. This happens when the body stops making enough GH to grow normally. It can start at any time in childhood.
What Are the Signs & Symptoms of Growth Hormone Deficiency?
Doctors check kids' height during regular checkups. Over time, doctors can see how fast kids grow. If a child is growing much slower than most other kids the same age, this is called growth failure.
One of the most visible signs of growth failure is a height that is much shorter than most other kids the same age. This is called short stature. But some kids can have growth failure even if they don't have short stature.
Other signs and symptoms of GH deficiency include:
- teeth that come in late
- muscle weakness
- in boys, a small penis at birth
- low blood sugars
What Causes Growth Hormone Deficiency?
Often, doctors don't know why a child has GH deficiency. When a cause is found, it's often related to problems with the pituitary gland or with the brain around the pituitary gland. Brain tumors, head injuries, and radiation treatment to the brain also can cause GH deficiency.
How Is Growth Hormone Deficiency Diagnosed?
If your child has growth failure or short stature, even without any other signs or symptoms, your doctor might send you to a pediatric endocrinologist, who specializes in children's growth and hormones.
The endocrinologist will ask about your child's growth and will do a careful exam. The doctor will order some tests to look for GH deficiency, such as:
- Blood tests. There are no easy tests to measure GH levels. GH is made in short bursts, mostly overnight. At other times, levels may be undetectable. This makes testing for it hard, because there is no way to know when the bursts will happen. So instead, doctors look at the levels of two proteins that have more stable levels and are markers of GH function: IGF-I (insulin-like growth factor I) and IGFPB-3 (insulin-like growth factor binding protein). They may also check for any other causes of short stature that are not related to growth hormone.
- Bone age X-rays. These are X-rays of one of your child's hands and wrists. An expert compares your child's X-rays with the X-rays of other children the same age, and gives the bones an age in years. If a child's bone age is much younger than their actual age, this might be a sign of GH deficiency.
- GH stimulation test. Doctors do this test when other tests suggest that a child might have GH deficiency. First, your child will need to fast by not eating or drinking anything for a certain number of hours, usually overnight. The doctor will give your child a medicine that should make the body produce a burst of GH. A nurse will then draw blood at a few different times to check the GH levels to try to catch the peak. Low GH levels confirm the diagnosis of growth hormone deficiency.
- Brain MRI. This very detailed picture of the brain helps doctors see if there is a problem with the pituitary gland or the brain that might be causing GH deficiency.
How Is Growth Hormone Deficiency Treated?
Treatment for GH deficiency is a growth hormone shot that replaces what the body isn’t making. Parents learn how to give these shots at home so kids don't need to go to the doctor's office for them.
The endocrinologist will tell you how often your child should come in when treatment starts. At each visit, the doctor:
- will check your child's growth
- may order blood tests to see how your child's body is responding to the medicine
- change the dose, if needed
Side effects are rare at the doses used for growth hormone deficiency. Tell the doctor if your child has headaches, vision changes, or limping.
Treatment usually lasts until growth is completed, in the late teens.
What Else Should I Know?
Growth hormone can increase the speed of growth in a child with growth hormone deficiency. Kids who start this treatment early often can catch up more than kids who begin treatment later.
As adults, our bodies make a much smaller amount of GH. So, many kids with GH deficiency and no other medical problems who get GH shots won't need them as adults.