September 3, 2010
Dear Mayo Clinic:
My four-year-old hasn't grown much since she was two. We were told she probably needs growth hormone. She's doing great otherwise. Is it possible she is just going to be very petite? What are the risks of waiting a little longer before giving her growth hormone?
Before moving forward with growth hormone therapy, your daughter should receive a thorough evaluation from an endocrinologist who has expertise in growth disorders to verify that growth hormone deficiency is the reason for her lack of growth. If she is indeed growth hormone deficient, it makes sense to start treatment as soon as possible. The earlier treatment begins, the better the response will be for increasing her final adult height.
Growth hormone is produced by the pituitary gland — a pea-sized structure at the base of the brain — to fuel childhood growth and help maintain tissues and organs throughout life. If a child's body doesn't produce enough growth hormone, his or her adult height may be less than would otherwise be expected. Children with growth hormone deficiency generally don't have trouble gaining weight; the disorder usually affects only height.
A normal rate of growth is about 2 inches per year. If your daughter is growing less, that's cause for concern. But a thorough assessment and accurate diagnosis are critical because not every child with poor growth has growth hormone deficiency. Other conditions that can influence growth include disorders of the gastrointestinal tract — such as inflammatory bowel disease and celiac disease — lung disorders and heart conditions, among others.
A diagnosis of growth hormone deficiency is made by evaluating a child's growth pattern over time, taking blood tests to measure hormone levels, and using imaging exams, such as an MRI, to assess the pituitary gland.
In some cases, growth hormone deficiency may be caused by disorders of the pituitary gland. These usually involve underdevelopment or under-functioning of the gland as a result of other factors, such as radiation, infection or trauma. In many cases, however, a specific reason for the deficiency cannot be determined.
If a diagnosis of growth hormone deficiency is confirmed, then growth hormone therapy is the best option. The treatment involves an injection of growth hormone once a day until a child's bone growth plates close, usually sometime during puberty. At that point, growth hormone will not be able to increase height any further. When a child starts taking growth hormone, typical growth is 3 to 4 inches during the first year. The rate of growth slows to about 2 inches per year after that.
Serious side effects from growth hormone treatment are rare. But, as with any injection, there is a risk of pain, bleeding and infection at the injection site. Other potential complications include increase in fluid pressure within the brain, an increase in blood sugar and changes in thyroid function.
Children taking growth hormone need careful medical supervision. Monitoring usually requires follow-up visits to an endocrinologist, as well as blood tests and X-rays to watch the child's rate of growth and adjust the amount of growth hormone needed, if necessary.
The sooner therapy begins in these children, the longer their period of growth. If your child has growth hormone deficiency and you decide to delay treatment, her ultimate height as an adult will be less, compared to what it would have been if treatment had started earlier.
If you haven't already done so, discuss your daughter's condition with and obtain a comprehensive evaluation of her medical situation from a pediatric endocrinologist familiar with growth disorders. Once you've received a clear diagnosis, you can work with that specialist to develop an appropriate treatment plan.
— Seema Kumar, M.D., Pediatric Endocrinology, Mayo Clinic, Rochester, Minn.