Gigantism Detailed Information

Gigantism is abnormally large growth due to an excess of growth hormone during childhood, before the bone growth plates have closed. Approximately 20% of patients with gigantism have MAS and may have either pituitary hyperplasia or adenomas. The most common cause of too much growth hormone release is a non-cancerous (benign) tumor of the pituitary gland. Other causes include carney complex, McCune-Albright syndrome (MAS), multiple endocrine neoplasia type 1 (MEN-1) and neurofibromatosis. If excess growth hormone occurs after normal bone growth has stopped, the condition is known as acromegaly.

The vertical growth in height that marks this condition is also accompanied by growth in muscles and organs, which makes the child extremely large for his or her age. The disorder can also delay puberty. Gigantism may begin at any age before epiphyseal fusion. The mean age for onset of acromegaly is in the third decade of life. For acromegaly, the delay from the insidious onset of symptoms to diagnosis is 5-15 years, with a mean delay of 8.7 years. Sign and Symptoms of Gigantism comprise thickening of the facial features, disproportionately large hands and feet with thick fingers and toes, augmented perspiration, weakness and secretion of breast milk.

Other symptoms of Gigantism include irregular menstruation, headache, and delayed onset of puberty and double vision or difficulty with peripheral vision. Surgery is the treatment of choice and can cure many cases. When surgery cannot completely eliminate the tumor, medication is also treatment of alternative. The most helpful medications are somatostatin analogs (such as octreotide or long-acting lanreotide), which reduce growth hormone release. Somatostatin analogs are very effective in treating patients with GH excess. Dopamine agonists (bromocriptine mesylate, cabergoline) have also been utilized to reduce growth hormone secretion.

A drug that blocks the result of increase hormone, pegvisomant, has recently become available. Radiation therapy has also been used to bring increase hormone levels to normal. However, it can take 5-10 years for the full effects to be seen and almost always leads to low levels of other pituitary hormones. Radiation has also been related with learning disabilities, obesity, and emotional changes in children. Surgery and radiation can both lead to deficiencies in other pituitary hormones, causing hypothyroidism, adrenal insufficiency, hypogonadism, and (rarely) diabetes insipidus.