Growth Hormone   

What is Growth Hormone?

Growth hormone is secreted by the acidophil cells of the Anterior pituitary gland. Its secretion is controlled by a dual system - Growth Hormone Releasing Hormone (GHRH) & Growth Hormone Release Inhibitory Hormone (GHRIH). These releasing and inhibitory hormones are secreted by Hypothalamus.

GROWTH HORMONE DEFICIENCY

In children the hyposecretion of GH causes Short Stature. This is usually due to inability to secrete GHRH rather than a primary pituitary abnormality. The next common cause is craniopharygioma.

Hypersecretion of GH is usually due to acidophil macroadenoma. Very rarely it could be due to ectopic production of GHRH by pancreatic tumour.

If GH hypersecretion occurs before the fusion of epiphysis GIGANTISM occurs. More commonly GH excess occurs in adult life after the fusion of epiphysis in which case ACROMEGALY occurs. If hypersecretion starts in adolescence and continues in the adult life then both the conditions may be combined.

CLINICAL FEATURES OF ACROMEGALY

Skin thickening, increased sweating,increased sebum production.

Enlargement of lips, nose and tongue.

Increased heel pad thickness.

Carpal tunnel syndrome

Large hands, large feet.

More than normal growth of lower jaw. Prominent supraorbital ridges and large frontal sinuses.

Kyphosis

Diabetes Mellitus, Hypertension

Headaches, visual defects, cranial nerves palsies

The pituitary tumour also affects other anterior pituitary hormone secretion. Level of Prolactin is increased in 30 % of the patients.

Management of GH deficiency

In children with GH deficiency GH therapy is indicated. 24 units/sq.m/week divided into daily bedtime dose given subcutaneously.

Patients with other cause of short stature like in Turner's syndrome may also benifit from GH therapy.

In case of Normal Short Child the role of GH therapy is not yet clear and is under clinical trails.

Causes of Short Stature

Isolated GH deficiency

Panhypopituitarism

Primary hypothyroidism

Cushing's syndrome

Achondroplasia- short limbs for spine

Mucopolysaccharidoses- short limbs and very short spine.

Turner's syndrome

Malabsorption syndromes- Crohn's disease,Coeliac disease, Colitis

Congenital heart diseases, Intrauterine growth retardation,Systemic illnesses like asthma, renal disease, malnutrition, psychosocial deprivation, Constitutional short stature with normal bone age.

Study Questions Growth Hormone Use in Children

Doctors are questioning the benefits of giving short children human growth hormone injections in an attempt to make them taller.

In a study appearing in the Feb. 18 issue of The New England Journal of Medicine, researchers found growth hormones can increase the height of healthy children by an average of two inches. However, the treatment is costly and there's no guarantee it will work.

Researchers at Stanford University in Stanford, Calif., studied 121 children who were considered short for no known medical reason. These children received daily growth hormone injections for two to 10 years. About 80 percent of the boys and girls who received the treatment and have since reached adulthood gained an extra two inches in height, researchers say. Twenty percent showed no height increase and only a few of the children reached the target height set by doctors. Researchers called the results "disappointing." Hormone growth therapy can cost anywhere from $10,000 to $25,000 a year.

While the U.S. Food and Drug Administration does not approve use of growth hormones for cosmetic use, the agency does approve of such treatments if deemed medically necessary.