Growth hormone deficiency is one of the endocrine (hormonal) disorders that can cause poor growth. In order for a child to grow properly, an important gland called the pituitary must release enough growth hormone called somatropin. Somatropin stimulates growth and cell reproduction. When the pituitary does not release enough somatropin, growth hormone deficiency (GHD) occurs and a child’s growth may slow down.1
Many factors influence the release of growth hormone from the pituitary gland in a child. These may include:
- High levels of physical and mental stress
- Types of prescription medications taken
- Amounts of other hormones produced in the body
- Amount of blood sugar released after eating
- Elevated levels of insulin-like growth factor-1 (IGF-1)
What causes growth hormone deficiency?
A Congenital Disorder
Sometimes, a child is born with growth hormone deficiency, possibly because of a problem with the pituitary gland. A congenital disorder may be the result of a genetic or chromosomal abnormality, or a problem during pregnancy.
An Acquired Disorder
In some cases, a disorder develops later in life. An acquired disorder refers to a condition that is not present at birth, and may result from illness or accident. Possible reasons why a child may develop an acquired disorder include illness—such as a tumor affecting the pituitary gland or a part of the brain called the hypothalamus—or trauma to the head that caused brain damage.
Idiopathic Growth Hormone Deficiency
Occasionally, doctors cannot find any reason for a child’s growth hormone deficiency. This is known as idiopathic growth hormone deficiency. Idiopathic growth hormone deficiency seems to occur in one of every 3,800 live births; exact rates of older children affected by this condition are harder to obtain.2
What are the signs of growth hormone deficiency?
From around the age of two and through puberty, children should grow, on average, two inches per year and gain roughly six pounds per year. Some children may not meet these average milestones, and that does not mean there is a growth hormone deficiency. However, in some cases it does.
Signs and symptoms of a possible growth hormone deficiency can include:
- Slow growth; less than two inches of growth per year3
- An immature appearance—making the child look younger than his or her peers
- A history of low blood sugar as an infant
How is growth hormone deficiency diagnosed?
If your child appears to have a growth problem, your pediatrician may refer you to a pediatric endocrinologist—a doctor who specializes in diagnosing, treating and managing disorders involving hormones and the glands that make them.
At your first visit, your pediatric endocrinologist will be interested in your child’s birth and medical history. The doctor may also ask you about family history and the adult height of both parents.
In addition to taking a patient history, the doctor will conduct a physical evaluation that may include the following:
- Laboratory evaluation: This may include blood tests to help rule out other illnesses.
- A stimulation test, also known as a STIM test: This test helps the doctor find out if your child’s body is producing enough growth hormone over time. During the test, your child receives a drug agent that can stimulate the pituitary gland to release GH. This is done in an effort to simulate the natural GH release from the pituitary gland. An IV is inserted into a vein, and a small amount of blood is taken, usually five times, 30 minutes apart. If the blood samples don’t show an increase in growth hormone, your healthcare team is one step closer to the diagnosis of growth hormone deficiency.
- Bone age X-rays: An X-ray of the left hand and wrist may be taken. The bone images will help determine the maturity of the bone and growth potential.
How is growth hormone deficiency treated?
Growth hormone deficiency is often treated with growth hormone replacement therapy. Growth hormone therapy helps bones grow, which causes an increase in height, but the process takes patience. It may take time before you begin to see a distinct change.
The structure of the growth hormone used in treatment is identical to the growth hormone produced by the pituitary gland. One brand of growth hormone, approved to treat appropriate growth hormone deficient children and adults, is called Saizen® (somatropin) for injection.