Pediatric Short Stature

The cause of a growth problem depends on the type of growth disorder in question. Some growth problems are genetic, while others may be caused by hormonal disorders or poor absorption of food. Causes for growth problems usually fall into the following categories:

• Familial short stature — Familial short stature is a tendency to follow the family's inherited short stature (shortness).
• Constitutional growth delay with delayed adolescence or delayed maturation — A child who tends to be shorter than average and who enters puberty later than average, but is growing at a normal rate. Most of these children tend to eventually grow to approximately the same height as their parents.
• Illnesses that affect the whole body (also called systemic diseases)
• Malnutrition — constant malnutrition prevents children from attaining their full growth potential; a well-balanced diet generally prevents or corrects this disorder. Malnutrition is the most common cause of growth failure around the world.
  • Digestive tract diseases
  • Kidney disease
  • Heart disease
  • Lung disease
  • Diabetes
  • Severe stress
• Endocrine (hormone) diseases
  • Lack of thyroid hormones — adequate production of the thyroid hormone is necessary for normal bone growth
  • Cushing's syndrome — Cushing's syndrome can be caused by myriad abnormalities that are the result of hypersecretion of corticosteroids by the adrenal gland
  • Growth hormone deficiency — There is a problem with the pituitary gland (small gland at the base of the brain) that secretes several hormones, including growth hormone
• Congenital (present at birth) problems in the tissues where growth occurs
  • Intrauterine growth restriction (IUGR) — Slow growth within the uterus occurs during a pregnancy. The baby is born smaller in weight and length than normal, in proportion to his/her short stature.
  • Chromosome abnormalities — Having too many or few chromosomes can result in health problems, including problems with growth. One chromosome abnormality that results from too few chromosomes is the following:
    • Turner syndrome — A genetic disorder seen in people with external female genitalia that causes them to be shorter than others and to not mature sexually as they grow into adulthood. The severity of these problems varies among affected individuals. Other health problems may also be present involving the heart or renal system (kidneys, etc.) Many conditions can be managed or corrected by medical treatment. Turner syndrome occurs in one in 2,500 females born. The features of Turner syndrome result from having a missing X chromosome in each of the body's cells.
  • Skeletal abnormalities (bone diseases or skeletal dysplasias) — There are more than 50 bone diseases that affect height and growth, many of which are genetic. The most common is achondroplasia, a type of dwarfism in which the child's arms and legs are short in proportion to his/her body length. Further, the head is often large and the trunk is normal size.
• Tall stature
  • Unusual tallness in girls — Some girls may grow unusually tall for their age if their parents are tall
  • Precocious puberty — This growth disorder is characterized by an early onset of adolescence in which a child is tall for his/her age initially but due to rapid bone maturity, growth stops at an early age and they may be short as adults
  • Genetic conditions — There are a few genetic conditions which result in tall stature where other health problems are also present
• Idiopathic — There is no known cause for the growth problem

Some growth problems may be immediately diagnosed at birth because the infant may be abnormally small for his/her age. However, many growth problems are noticed much later when the child appears smaller than his/her classmates or when growth appears to be insignificant over a period of a year. The primary symptom that may indicate a growth problem is when a child grows less than two inches a year after his/her second birthday. Symptoms of growth problems may resemble other problems or medical conditions. Always consult your child's physician for a diagnosis.

Diagnosis of a growth problem must be made by your child's physician. The method used for diagnosis will depend on the type of growth disorder presented. In addition to a complete medical history and physical examination, diagnostic tests may include:

• Observing the child's health and growth over a period of time
• Blood tests (to rule out hormone, chromosomal or other disorders associated with growth failure)
• Bone X-rays – electromagnetic energy used to produce images of bones and internal organs onto film (to determine maturity and growth potential of bones)
• Examining the functions of the pituitary gland, which produces and secretes the growth hormone

Growth hormone deficiency, as the name implies, is the absence or deficiency of growth hormone produced by the pituitary gland to stimulate the body to grow. Growth hormone deficiency may occur during infancy or later in childhood. Without treatment, most children with growth hormone deficiency will not reach a height of 5 feet.

Growth hormones are produced by the pituitary gland, which is attached to the hypothalamus (a part of the brain) located at the base of the brain. Sometimes referred to as the master gland of the endocrine system, the pituitary gland controls the functions of the other endocrine glands through the secretion of certain hormones and produces human growth hormone. When the pituitary gland or the hypothalamus are malformed or damaged, growth hormone deficiency may result. Damage to the pituitary gland or hypothalamus may occur as a result of abnormal formation of these organs before a child is born (congenital, or present at birth) or as a result of damage that occurred during or after birth (acquired).

Researchers have found that growth hormone deficiency may also be part of a genetic syndrome. However, in some cases, the cause of growth hormone deficiency is unknown (idiopathic).

The primary symptom of growth hormone deficiency is a noticeable slow growth (less than two inches per year), although the body has normal proportions. The child with growth hormone deficiency may also have:

• Immature face, meaning he/she looks much younger than his/her peers
• Chubby body build

It is important to note that growth hormone deficiency does not affect the child's intelligence and each child experiences symptoms differently. The symptoms of growth hormone deficiency may resemble other problems or medical conditions. Always consult your child's physician for a diagnosis.

Before a growth hormone deficiency diagnosis can be made, your child's physician may have to rule out other disorders first, including short stature (inherited family shortness) and thyroid hormone deficiency. In addition to a complete medical history and physical examination, diagnostic procedures for growth hormone deficiency may include the following:

• Monitoring the child's growth over a period of time
• A review of the mother's pregnancy, labor and delivery
• Bone (hand and wrist) X-rays – electromagnetic energy used to produce images of bones and internal organs onto film (to determine bone maturity and growth potential)
• IGF-1 (or somatomedin) test – produced when the liver and other tissues are stimulated by growth hormone
• Scan of the pituitary gland (to detect abnormalities)
• Artificial stimulation of growth hormone secretion followed by measurement of growth hormone release over a period of time
• Measurement of growth hormone in the blood during an overnight stay in the hospital (two-thirds of the production of growth hormone occurs during deep sleep)

Specific treatment for growth problems will be determined by your child's physician based on:

• Your child's age, overall health and medical history
• Extent of the condition
• Your child's tolerance for specific medications, procedures or therapies
• Expectations for the course of the condition
• Opinion or preference

Treatment of growth problems will depend on the type of growth disorder presented. If a medical condition causes the growth problem, treatment of that condition may alleviate the growth problem.

Specific treatment for growth hormone deficiency will be determined by your child's physician based on:

• Your child's age, overall health and medical history
• Extent of the condition
• Your child's tolerance for specific medications, procedures or therapies
• Expectations for the course of the condition
• Opinion or preference

Once growth hormone deficiency has been diagnosed, treatment for the disorder involves regular injections of human growth hormone (some children receive daily injections, while others receive injections several times a week). Treatment usually lasts several years, although results are often seen as soon as three to four months after the injections are started. The earlier the treatment for growth hormone deficiency is started, the better chance the child will have of attaining normal or near-normal adult height. However, not all children respond well to growth hormone treatment.

The American Academy of Pediatrics (AAP) recommends that therapy with growth hormone is medically and ethically acceptable for children:

• With classic growth hormone deficiency
  
• Awaiting kidney transplantation who have chronic renal insufficiency
  
• With Turner syndrome (females)
  
• Whose extreme short stature prohibits their participation in everyday activities and who have a condition for which the efficacy of growth hormone therapy has been demonstrated

While there are many potential side effects, researchers generally agree that treatment with human growth hormone is safe and effective. Until the 1980s, the only source of human growth hormone was from the pituitary glands of deceased people where an increased chance of transmission of human diseases from human growth hormone existed. In 1985, a biosynthetic growth hormone was approved by the U.S. Food and Drug Administration (FDA) eliminating the risk of disease transmission and creating an unlimited supply of growth hormone. Consult your child's physician for more information.