Growth hormone deficiency

Definition

Growth hormone deficiency refers to abnormally short height in childhood due to the lack of growth hormone.

See also: Short stature

Alternative Names

Panhypopituitarism; Dwarfism; Pituitary dwarfism; Recombinant human GH (rhGH); Acquired growth hormone deficiency; Congenital growth hormone deficiency

Causes, incidence, and risk factors

An abnormally short height in childhood (called short stature) may occur if there is not enough growth hormone produced. Growth hormone is produced in the pituitary gland, which is located at the base of the brain.

Most of the time, no cause is found.

Growth hormone deficiency may be present at birth (congenital) or acquired as the result of an injury or medical condition.

Children with physical defects of the face and skull, such as cleft lip or cleft palate, can also have decreased growth hormone levels.

Growth hormone deficiency also can be caused by severe brain injury.

Growth retardation may first be noticed in infancy and continue throughout childhood. The pediatrician will usually plot the child's "growth curve" on a standardized growth chart. The child's growth may range from flat (no growth) to very shallow (minimal growth). Normal puberty may or may not occur, depending on how well the pituitary gland can produce hormones other than growth hormone.

Although it is uncommon, growth hormone deficiency may also be diagnosed in adults. Possible causes include:

• Hormonal problems involving the pituitary gland or hypothalamus
• Brain radiation treatments for cancer
• Severe head injury

Symptoms

Children with growth hormone deficiency have a slow rate of growth, usually less than 2 inches per year. The slow growth may not appear until a child is 2 or 3 years old.

The child will be much shorter than most or all children of the same age and gender.

Children with growth hormone deficiency still have normal body proportions, as well as normal intelligence. However, their face often appears younger than children of the same age. They may also have a chubby body build.

In older children, puberty may come late or may not come at all.

Signs and tests

A physical examination including weight, height, and body proportions will show signs of slowed growth rate. The child will not follow the normal growth curves.

Tests may include the following:

• Dual energy x-ray absorptiometry (DEXA) scans can also determine bone age.
• Hand x-ray (usually the left hand) can determine bone age. Normally, the size and shape of bones change as a person grows. These changes can be seen on an x-ray and usually follow a pattern as a child grows older.
• Measuring growth hormone and binding protein levels (IGF-I and IGFBP-3) will show whether the growth problem is caused by a problem with the pituitary gland.
• MRI of the head can show the hypothalamus and pituitary glands.
• Tests to measure other hormone levels (lack of growth hormone may not be the only problem) may be done.
• X-ray of the head may show problems with the skull.

Treatment

Treatment involves growth hormone injections given at home. Patients may receive growth hormone several times a week or once a day.

Serious side effects of growth hormone therapy are rare. The most common side effects are:

• Fluid retention
• Muscle and joint aches

Expectations (prognosis)

The earlier the condition is treated, the better the chance that a child will grow to be a near-normal adult height. Many children gain 4 or more inches over the first year and 3 or more inches during the next 2 years. The rate of growth improvement then slowly decreases.

Growth hormone replacement therapy does not work for all children.

Complications

If left untreated, growth hormone deficiency will lead to short stature and delayed puberty.

Growth hormone deficiency may occur with deficiencies of other hormones, including the following:

• Thyrotropins (control production of thyroid hormones)
• Vasopressin (controls water balance in the body)
• Gonadotropins (control production of male and female sex hormones)
• Adrenocorticotrophic hormone or ACTH (controls the adrenal gland and its production of cortisol, DHEA, and other hormones)

Calling your health care provider

Call your health care provider if your child seems abnormally short for his or her age.

Prevention

Most cases are not preventable.

Review your child's growth chart with your physician after each check-up. If your child's growth rate is dropping or your child's projected adult height is much shorter than an average height of both parents, evaluation by a specialist is recommended.

References

Parks JS, Felner EI. Hypopituitarism. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 558.

Reiter EO, Rosenfeld RG. Normal and aberrant growth. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 23.