Growth Hormone Deficiency

Background

 

Growth hormone deficiency refers to an abnormally short height in childhood due to a lack of growth hormone. The pituitary gland, which is located at the base of the brain, produces growth hormone. Hormones in the brain tell the pituitary gland how much growth hormone must be produced. Growth hormone then enters the blood and stimulates the liver to produce a hormone called insulin-like growth factor (IGF-1). This hormone plays a key role in childhood growth.

 

Causes

Short stature, or abnormally short height, may occur in childhood if not enough growth hormone is produced. Often, there is no single cause of growth hormone deficiency. In some children, growth hormone deficiency may be congenital, or present at birth. However, growth hormone deficiency is usually not passed from parent to child. The deficiency can also develop after birth as a result of brain injury, tumor or a medical condition.

 

Adults rarely are diagnosed with growth hormone deficiency. Some causes may include brain radiation treatments for cancer, hormonal problems involving the pituitary gland or hypothalamus or severe head injury.

 

Symptoms

Children with growth hormone deficiency have a slow or flat growth rate. This is defined as usually less than two inches per year. Often this does not appear until a child is two or three years old. A child will still have normal body proportions and intelligence but their face often appears younger than children of the same age. In addition, they may also have a chubby body build. Puberty may appear later or not at all in older children.

 

Diagnosis

Physical examination and several blood tests are performed to diagnosis children with growth hormone deficiency. During the physical examination, the doctor will measure the child’s weight, height and body proportions. A growth chart is used to compare a child’s current height and how fast he or she is growing compared to other children the same age and gender. A child with growth hormone deficiency will not follow the normal growth curves and will show signs of a slowed growth rate.

 

The following blood tests are used to help diagnose growth hormone deficiency:

 

• GNRH-arginine.

 

• Growth hormone levels in the blood.

 

• Growth hormone stimulation test.

 

• Growth hormone and binding protein levels (IGF-1 and IGFBP-3) determines if there is a problem with the pituitary gland.

 

• Insulin tolerance test (ITT) – often used to diagnose adults.

 

• Tests to measure levels of other hormones made by the pituitary gland.

 

Imaging or x-ray tests may include the following:

 

• Dual energy x-ray absorptiometry (DEXA) scans can also determine bone age.

 

• Hand x-ray to measure the size and shape of bones that change as a person grows.

 

• MRI of the head examines the hypothalamus and pituitary glands.

 

Treatment

 

Specialty drug list

 

The earlier the condition is treated the better the chance a child has to grow to be a near-normal adult height. Treatment involves receiving injections of growth hormone. Children may gain four or more inches over the first year, and three or more inches during the next two years. After two years, the growth rate slowly decreases.

 

Side effects

The most common side effects of growth hormone therapy are fluid retention and muscle and joint aches. The fluid retention some patients experience often occurs as swelling in the feet and ankles. In addition, pain, redness and swelling at the site of injection can be bothersome for patients.

 

Resources

 

There are many resources and organizations available to help, providing support, advocacy and information:

 

The Human Growth Foundation
www.hgfound.org

 

The Magic Foundation
www.magicfoundation.org

 

References

National Institutes of Health. NLB. Growth hormone deficiency–children. A.D.A.M. Medical Encyclopedia. Atlanta (GA): A.D.A.M.; 2011.