Gigantism: Causes, Symptoms, Diagnosis, Treatment, and Prevention
An abnormal growth condition in children is called gigantism, which occurs when the pituitary gland, a small gland at the base of the brain, produces too much growth hormone (GH). Growth hormone is responsible for stimulating bones, muscles, and organ growth. A hormone called somatostatin normally regulates the pituitary gland's production of growth hormone. However, in some cases, somatostatin is not effective or there is a tumor in the pituitary gland that secretes excess GH. This leads to gigantism.
Causes of Gigantism
Gigantism is most often caused by pituitary adenomas, a benign tumor located in the pituitary gland. There are two types of pituitary adenomas: functional and non-functioning. Functioning pituitary adenomas produce hormones that affect various bodily functions, such as growth hormone, prolactin, or ACTH. While non-functioning pituitary adenomas do not produce hormones, they can compress surrounding tissues and interfere with pituitary function.
Other rare causes of gigantism include:
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Genetic disorders, such as multiple endocrine neoplasia type 1 (MEN1), Carney complex, McCune-Albright syndrome, or familial isolated pituitary adenoma (FIPA)
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Brain injuries, infections, or radiation that damage the pituitary gland or the hypothalamus, the part of the brain that controls the pituitary gland
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Excess production of GH by other tumors in the body, such as lung, pancreas, or adrenal tumors
Symptoms of Gigantism
The main symptom of gigantism is excessive growth in height, weight, and body proportions. A child with gigantism may grow taller than 7 feet (2.1 meters) and weigh more than 300 pounds (136 kilograms). Their hands, feet, head, and facial features may also be enlarged. Symptoms of gigantism may include:
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Headaches, vision problems, or nausea due to the pressure of the pituitary tumor on the brain
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Delayed puberty, irregular periods, or infertility due to the hormonal imbalance
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Weakness, fatigue, or muscle pain due to the increased metabolic demands
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Joint problems, arthritis, or scoliosis due to the stress on the bones and cartilage
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Diabetes, high blood pressure, or heart disease due to the insulin resistance and cardiovascular complications
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Sleep apnea, a condition where breathing stops and starts during sleep, due to the enlarged tongue and soft tissues in the throat
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Skin problems, such as acne, excessive sweating, or skin tags, due to the increased oil production and skin growth
Diagnosis of Gigantism
To diagnose gigantism, a doctor will perform a physical examination, measure the height and weight, and ask about the medical history and symptoms. The doctor will also order some tests to confirm the diagnosis and identify the cause of gigantism. These tests may include:
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Blood tests to measure the levels of GH, IGF-1 (a hormone that reflects GH activity), and other hormones that may be affected by the pituitary tumor
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Urine tests to measure the amount of GH and IGF-1 excreted in the urine over 24 hours
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Oral glucose tolerance test (OGTT) to check how the body responds to sugar intake. Normally, GH levels should decrease after drinking a sugary solution, but in gigantism, they remain high or increase
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Imaging tests, such as MRI or CT scan, to visualize the pituitary gland and detect any tumors or abnormalities
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Genetic tests to screen for any inherited disorders that may cause gigantism
Treatment of Gigantism
The goal of treatment for gigantism is to reduce the excess GH production, shrink or remove the pituitary tumor, and prevent or manage the complications. The treatment options for gigantism may include:
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A pituitary tumor is removed either through the nose (transsphenoidal surgery) or through the skull (transcranial surgery). This is usually the most effective treatment for gigantism, especially if the tumor is small and confined to the pituitary.
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In order to lower GH levels, medications such as somatostatin analogs (octreotide, lanreotide, or pasireotide), dopamine agonists (cabergoline or bromocriptine), or GH receptor antagonists (pegvisomant) are available. During or after surgery, or if surgery is not possible or effective, these drugs can be used
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Radiation therapy to destroy the remaining tumor cells or prevent them from growing back. It can be done through external beams of radiation (conventional radiotherapy) or radioactive seeds implanted into the tumor (stereotactic radiosurgery). In cases where surgery and medications fail or are not appropriate, radiation therapy is usually used.
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As a result of pituitary damage, some hormones, such as thyroid hormone, cortisol, estrogen, or testosterone, may be deficient. Symptoms such as fatigue, weight gain, or low libido can be prevented by restoring the body's normal function.
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Changes in lifestyle, such as eating a balanced diet, exercising regularly, managing stress, and getting enough sleep, can help improve overall health and quality of life. By doing so, you may be able to prevent or control complications of gigantism, such as diabetes, high blood pressure, or heart disease.
Prevention of Gigantism
Since gigantism is usually caused by factors that are beyond one's control, such as genetic mutations or tumors, there is no known way to prevent it. The symptoms and complications of gigantism can be reduced or prevented if they are detected and treated early. Therefore, when a child displays signs of abnormal growth or other gigantism symptoms, it is important to consult a doctor. In order to ensure the effectiveness of the treatment and to adjust the dosage or type of medication if necessary, regular follow-up and monitoring are also essential.
