Acromegaly, known as gigantism in children, is a rare, chronic disorder caused by an overproduction of growth hormone by the pituitary gland, resulting in increased growth in bone and soft tissue and leading to other problems throughout the body.
The pituitary, a peanut-size organ located at the base of the brain, is the most important gland in the body’s endocrine, or hormonal, system. It produces a number of essential hormones; one of these, human growth hormone (HGH or somatotropin), is responsible for regulating growth during childhood.
Normally, as people reach adulthood, less HGH is produced. Overproduction of HGH in children results in exaggerated height. (The most dramatic case of gigantism on record is a child who grew to a height of nearly nine feet.) When onset of the disorder occurs during adulthood (acromegaly), bones can no longer increase in length but progressively thicken instead. This results in gradual enlargement of the hands, feet, jaw, forehead, nose, and ears and produces the coarse facial features characteristic of the disorder.
The internal organs also become abnormally enlarged. Thus, acromegaly often reduces life expectancy and, if left untreated, may lead to blindness, arthritis, infertility, diabetes, high blood pressure, heart valve failure, and coronary artery disease.
What Causes Acromegaly?
- Acromegaly is caused by oversecretion of human growth hormone (HGH), which produces changes throughout the body.
- A benign pituitary tumor (adenoma) is the most common cause of HGH overproduction.
- Rarely, a tumor in the hypothalamus (the region of the brain directly behind the pituitary gland) or elsewhere may overstimulate production of HGH.
Symptoms of Acromegaly
- In adults: enlarged hands, feet, forehead, and jaw bones; broadened head and neck; coarsened facial features; widely spaced teeth; excessive snoring; excessive sweating; impotence in men; cessation of menstrual periods (amenorrhea) and excess facial hair (hirsutism) in women
- In children: excessive height due to abrupt, accelerated growth (not to be confused with normal adolescent growth spurts)
- In both children and adults: fatigue and muscle weakness; profuse sweating; weight gain; oily skin; sinus congestion; increased tongue size; hollow-sounding voice; oversleeping; joint pain; tingling sensations in the hands; sudden mood changes
- Headaches and impaired vision may occur as tumor growth exerts pressure within the skull
- Patient history and physical examination, including visual-field tests.
- Blood tests revealing elevated levels of HGH that are not fully reduced by administration of glucose.
- Glucose tolerance test to determine if growth hormone levels drop.
- Measurement of elevated levels of somatomedin-C (IGF-1) in the blood.
- CT (computed tomography) scans and MRI (magnetic resonance imaging) to detect a pituitary tumor.
- X-rays to detect thickening of bones
How Acromegaly Is Treated
- Surgical removal of the underlying tumor is the treatment of choice. It is not uncommon for HGH levels to return to normal within hours of surgery and for soft tissue (but not bony tissue) enlargement to subside rapidly.
- Medications after surgery such as octreotide, pergolide, bromocriptine, pegvisomant and sometimes cabergoline may be prescribed to decrease tumor size and regulate HGH secretion.
- Radiation, alone or following surgery, may be performed to shrink the tumor (or prevent its recurrence) but it may require 5 to 10 years to work.
- In some cases, lifetime hormone replacement therapy with thyroid or adrenal-steroid hormones may be necessary if surgery or radiation damages the remaining pituitary gland.
When to Call a Doctor
- See a doctor if you or your child develop symptoms of acromegaly or gigantism.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media