What Is Growth Hormone Deficiency in Children?
Growth hormone deficiency is a disorder that involves the pituitary gland, which controls the production of growth hormone in the body. The pituitary gland is located at the base of the brain behind the back of the nose and near the hypothalamus. The hypothalamus is a region of the brain that stimulates the secretion of growth hormone from the pituitary gland into the body. If the pituitary gland or the hypothalamus are damaged and the production of growth hormone is low or absent then a child's growth may be slower than normal. Growth hormone is supposed to be released in bursts into the body throughout the day and night. Growth hormone is essential for children to grow at a normal rate.
Growth hormone deficiency can occur when your child is an infant but also can occur later on in childhood. Children who are diagnosed and treated early on for growth hormone deficiency typically reach a normal height.
What Is the Average or "Normal" Growth for a Child Per Year?
The first year of your child's life they are typically growing very rapidly. On average babies grow about 10 inches in length and triple in weight. Between the ages of 1 and 2 a child typically grows about 5 inches a year and between the ages of 2 and 3 they grow about 3 inches per year. After the age of 3, a child's growth rate slows down. On average they will grown at a steady pace of 2 1/2 inches per year until they reach adolescence. You can help your child grow at a "normal" rate by assuring they have good nutrition, get regular exercise, and are sleeping enough. Every child's growth rate is different and much of it is dependent on genetics and cannot be controlled.
What Causes Growth Hormone Deficiency?
Often times the cause of growth hormone deficiency in children is unknown. Since every child is different there can be numerous different causes of growth hormone deficiency. Growth hormone deficiency may be present at birth but could also have been causes by other medical conditions or injuries. Some causes include:
- The pituitary gland did not develop properly and is not producing enough growth hormone.
- A mass or tumor is affecting or preventing the pituitary gland from producing growth hormone.
- Radiation therapy to treat brain tumors or other types of cancers near the hypothalamus or pituitary gland.
- Inflammation of the pituitary gland
- Head trauma
- Physical defects of the face or skull
- Other genetic diseases that interfere with the pituitary gland
What Are the Symptoms of Growth Hormone Deficiency?
The symptoms of growth hormone deficiency vary depending on the severity of your child's case. Some of the most common symptoms of growth hormone deficiency in children include:
- A short stature compared to other children the same age and gender as your child
- A slow growth rate
- A younger looking appearance
- Increased body and belly fat (around the waist area)
- High-pitched voice
- Delayed bone age (found through an X-ray)
- Low blood sugar
Children with growth hormone deficiency tend to still have normal body proportions. Your child's intelligence will not be affected if they have growth hormone deficiency. It is important to remember that these symptoms could also be signs of other growth problems and conditions, so always be sure to consult with your doctor for an accurate diagnosis.
How Will My Child Be Diagnosed with Growth Hormone Deficiency?
The Pediatric Endocrinologists at MassGeneral Hospital for Children will evaluate your child's height and growth rate to determine how to proceed with treatment. These doctors specialize in treating children and adolescents with endocrine disorders, which include disorders of growth. Your child will receive personal treatment from one of our endocrinologists along with state of the art evaluation and therapy.
Your child's endocrinologist will need to gather information about the family history. They will need to know the heights of his or her parents and other relatives. Additionally, they will need to know if there are any existing or past health problems in the family along with details about the mother's pregnancy with the child. Your child's height and weight will be measured in order to plot them on a growth chart. A growth chart will display a comparison of your child's growth to other children the same age. A child with growth hormone deficiency will have a height that levels off and does not reach the average growth curve. Next, your child's doctor will ask further questions about your child's nutrition, past illnesses, injuries, along with various other questions regarding their general health. Further tests will be conducted if your child's doctor thinks they may have growth hormone deficiency.
How Will My Child Be Tested for Growth Hormone Deficiency?
There are many different ways the physicians at MassGeneral Hospital for Children will test for growth hormone deficiency. The four types of tests include a bone age X-ray, a blood test, a brain MRI, and a growth hormone stimulation test.
Bone Age X-Ray
Your child's endocrinologists will take an X-ray of your child's left hand and wrist to determine their bone age. The areas in the fingers and wrists contain growth plates and the doctor will be able to tell the maturity of your child's skeletal system based on the appearance of these areas. Children with growth hormone deficiency often have delayed bone age which means they have immature bones relative to their age. For example, your child might be 12-years-old, but his or her bones might have the maturity level expected for a 9-year-old – this would be called a delayed bone age.
Your child may be given a blood test to test the levels of two proteins in their body. These two proteins are called IGF-1 and IGFBP-3. They are made in the body when growth hormone is released. But when your child's growth hormone levels are low, then the levels of these proteins may also be low, indicating that your child has growth hormone deficiency.
Your child's doctor may conduct a brain MRI, which is a special X-ray that shows if the pituitary gland is growing normally. It also can indicate whether it is safe to treat your child with growth hormone medication.