The pituitary gland, a small gland in the brain, produces a number of hormones that regulate the human body. One of these, growth hormone, is responsible for maintaining your child's rate of growth. If the pituitary gland does not produce enough of this hormone, your child will not grow at a normal rate.

Of course, kids come in all shapes and sizes, and your child may simply be small for his age. Chances are, if either or both his parents are on the short side, a child will be smaller than average as well.

However, if your child is the same height as children two years younger (that is, two standard deviations from the norm) or if his growth starts to deviate from the pattern on his growth chart, your doctor will recommend further evaluation. Kids with growth hormone deficiency often grow normally until they are two or three, at which point their growth slows noticeably. Most children with growth hormone deficiency grow less than two inches a year, while those without grow between 3 and 6 inches a year.

After ruling out other possible causes, such as kidney, lung, or heart disease, your doctor may recommend a series of tests to determine if your child's endocrine system -- the system of hormones that regulates his body -- is functioning normally. He may oversee these tests himself, or he may refer you to a pediatric endocrinologist, a specialist in hormone disorders. One purpose of these tests will be to compare your child's growth with that of other children. For this reason he will probably be given be a bone age test, in which his hand and wrist are X-rayed and compared to other children's.

Your doctor may also order an MRI of your child's pituitary gland to determine if there is a tumor present or any other problem causing it to malfunction. Finally, your child may be given tests to determine the amount of growth hormone in his bloodstream. This test will require your child to fast the night before, and then in the morning he will be given a medication to stimulate the production of growth hormone.

Although there is no generally accepted standard for growth hormone, a peak level below 10 ug/L has traditionally been accepted as the standard to determine that there is a deficiency. Doctors often order more than one assay, or test, for growth hormone before determining whether or not there is a deficiency. Because our bodies produce most of our growth hormone at night, your doctor also may want to hospitalize your child and test the level of growth hormone in his blood at regular intervals throughout the night.

There are many reasons why the pituitary gland may not be putting out enough growth hormone. Your child's condition may be congenital, which means his pituitary gland may have been affected while he was developing in utero. Or your child's pituitary gland may have been damaged by disease or a traumatic event, for example, a childhood bout of meningitis. Children who have been treated for cancer may later suffer from growth hormone deficiency because their pituitary glands were affected by the treatment.

"The pituitary gland is very sensitive to radiation," says Dr. David Cook, MD, professor of medicine at Oregon Health and Science University. "Of all the hormones, growth hormone is the most sensitive and the most easily lost."

If tests reveal that your child is deficient in growth hormone, your doctor will likely recommend beginning treatment with growth hormone injections to replace the missing hormone.

If no cause for the deficiency can be found, your child will be diagnosed with idiopathic growth hormone deficiency.

-- Melanie Haiken, the former health editor of Parenting magazine, is a freelance health and medical reporter based in San Rafael, California.

References

Last updated September 28, 2009
Copyright © 2003 Consumer Health Interactive

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