Alterations in Growth

Normal variations

Changing patterns of growth during infancy
For a variety of reasons, a child may be born smaller or larger than would be expected based on the physical size of the parents and other family members (the family's genetic potential). When this happens, the child may show a growth pattern called "catch-up" or "catch-down," depending on the difference between size at birth and expected size. This means that the child's length or height may cross over one or two percentile lines upward or downward, then stabilize once it reaches the percentile appropriate for the genetic potential. This is generally a normal pattern during the first two years or so of life.

Constitutional growth delay

Constitutional growth delay (also known as constitutional delay of growth and puberty, or constitutional delay of growth and adolescence) refers to a fairly common variation of the growth process in which growth occurs more slowly than average.

Such children are often the smallest in their class at school. The physical changes of puberty and the pubertal growth spurt occur later in children with constitutional growth delay, around ages 13 to 14 for girls and 15 to 16 for boys. These children are often referred to as "late bloomers." There may be a history of a similar growth pattern in one or more family members. This delayed growth and development may cause some emotional stress for the child; if so, medical or psychological therapy may be helpful.

Hormone Deficiency or Excess

Thyroid hormone deficiency
The thyroid gland, located at the base of the neck, produces thyroid hormones that have a direct effect on growth and metabolism.

Hypothyroidism, or insufficient secretion of thyroid hormones, may result in slowing of growth.

Hypothyroidism that develops during childhood usually develops slowly, often making diagnosis difficult. A decrease in the speed of growth may be one of the earliest signs of the condition. Some other symptoms of hypothyroidism include dry skin and hair, fatigue, constipation and weight gain. Blood tests can confirm a diagnosis of hypothyroidism. Treatment consists of providing thyroid hormone in the form of tablets given daily.

Excessive cortisol

The adrenal glands, located above the kidneys, produce a number of hormones, including an important hormone called cortisol. Cortisol affects many processes in the body, such as glucose production, fat storage and helping the body cope with stress. When above-normal amounts of cortisol are released by the adrenal glands, many processes and organs in the body are affected. In childhood, one consequence of excessive cortisol may be inhibition of growth. Other symptoms may include fatigue, muscle weakness, weight gain, easy bruising and thinning of the skin.

Detailed testing is required to diagnose excessive cortisol production, and treatment varies according to the cause of the excess cortisol production.

High doses of cortisol-like medications are sometimes required to treat severe conditions such as asthma or arthritis. This can also cause a slowing of growth.

Growth hormone deficiency

The pituitary gland normally produces growth hormone and releases it into the bloodstream. Growth hormone deficiency is a condition in which the pituitary gland produces less than the normal amount of growth hormone, which may result in slow growth, short stature, and disturbances of metabolism.

There are a number of possible reasons for poor growth hormone production in childhood. For example, there may have been improper formation of the hypothalamus (the region of the brain that controls the pituitary gland) or pituitary gland itself before birth.

Head injuries, brain tumors, and brain damage due to disease, infection or radiation can also cause poor functioning of the pituitary gland. In many cases, detailed testing will be needed to find the cause of the subnormal growth hormone production.

Other causes of growth disturbance

Turner syndrome
Turner syndrome, a genetic alteration due to a partial or complete absence of one X chromosome in girls, is one of the most common causes of extreme short stature in girls. Affected girls usually fail to enter puberty and may have a number of other medical conditions, such as heart or kidney problems. Any condition that is present at birth, such as Turner syndrome, is called a congenital condition. Other examples of congenital conditions include heart defects, skeletal (bone) abnormalities and alterations of chromosomes.

Idiopathic short stature

The term "idiopathic" short stature is used to describe short stature for which there is no known, identifiable cause. However, children with idiopathic short stature likely have another cause for their poor growth for which there is currently no known medical explanation. General health in these children is usually good. However, they tend to have lower than average blood levels of IGF-I.

Acquired growth disorders

Illness
Chronic illnesses, such as diseases of the kidneys, heart, lungs or gastrointestinal tract (bowels) can also affect growth. Normal growth should resume if the disease can be effectively treated. However, adult height may be reduced if the disease is severe or prolonged, or if it is difficult to treat, as may be the case with kidney and severe bowel diseases.

Medication

Certain medications used to treat childhood illnesses, such as asthma or arthritis, can suppress growth. Other medications that may affect growth, in some cases, include those used to treat attention deficit and hyperactivity disorders. If it appears that a medication is affecting your child's growth, your child's doctor may recommend changing the dose or trying another medication. Of course, any changes should be made only under medical supervision.