About Gigantism

Overview

Gigantism, also known as growth hormone excess, is a condition characterized by abnormally large growth due to an excess of growth hormone (GH) during childhood, before the bone growth plates have closed. This excessive production of GH leads to increased growth in height, muscles, and organs, making the affected child much larger than their peers. Some common symptoms of gigantism include delayed puberty, double vision or difficulty with side vision, prominent forehead and jaw, headache, increased sweating, irregular periods (in females), large hands and feet with thick fingers and toes, thickening of facial features, and weakness. The most common cause of gigantism is a noncancerous tumor of the pituitary gland that stimulates excessive GH production. However, it can also be caused by underlying conditions that may lead to a pituitary tumor. Genetic changes in the GPR101 gene have also been identified as a cause in some cases.

Causes and Risk Factors

Gigantism occurs during childhood and adolescence when the bones are still growing. The disease causes of gigantism (growth hormone excess) include:

Most commonly, it is caused by a benign tumor called a pituitary adenoma in the pituitary gland. These tumors can produce excess growth hormone, leading to gigantism.
In some cases, gigantism may be related to other conditions such as Carney complex, McCune-Albright syndrome, multiple endocrine neoplasia type 1 or 4, neurofibromatosis, or a GPR101 gene mutation.
Rarely, tumors in other parts of the body like the lungs, pancreas, hypothalamus, adrenal glands, chest, or abdomen can cause gigantism by secreting hormones that trigger the pituitary gland to produce excess growth hormone.

It's important to note that the development of pituitary adenomas can sometimes be influenced by certain genetic syndromes like Carney complex, McCune-Albright syndrome, multiple endocrine neoplasia type 1 or 4, and neurofibromatosis. These genetic syndromes cannot be changed. It is always recommended to consult with a healthcare professional for personalized advice regarding risk factors for gigantism.

Symptoms

Early symptoms of gigantism (growth hormone excess) include:

Excessive growth in height, muscles, and organs
Enlarged hands and feet with thick fingers and toes
Thickening of facial features
Prominent forehead and jaw
Delayed puberty
Irregular menstrual periods (in females)
Difficulty with side vision or double vision
Increased sweating
Weakness

As the condition progresses or becomes more severe, additional symptoms may occur:

Headaches
Joint pain
Difficulty sleeping
Oily skin
Irregular heartbeat
Enlarged tongue, nose, and lips
Deepening voice in boys

It's important to note that these symptoms can vary from person to person. If you or someone you know is experiencing any of these symptoms, it's recommended to consult with a healthcare professional for an accurate diagnosis and appropriate treatment.

Diagnosis

To diagnose gigantism (growth hormone excess), doctors commonly perform the following examinations, tests, and procedures:

Medical history: Your doctor will ask about your family history and current symptoms to determine if further tests are necessary.
Physical examination: This allows your doctor to look for physical signs such as an enlarged tongue or prominent facial bones.
Blood tests: High levels of growth hormone and insulin-like growth factor-1 (IGF-1) are characteristic of gigantism. Your doctor may also check other hormones like cortisol and thyroid hormone.
Imaging tests: If a pituitary adenoma is suspected, your doctor may order an MRI (magnetic resonance imaging) or CT (computed tomography) scan to visualize the tumor's size and location.

To determine the severity of gigantism, additional examinations, tests, and procedures may include:

Oral glucose tolerance test: This test measures growth hormone levels after drinking a sugary liquid. If growth hormone levels remain elevated, it confirms the diagnosis of gigantism.
MRI scan: If a pituitary tumor cannot be found, other imaging tests may be ordered to identify nonpituitary tumors that could be causing elevated growth hormone levels.

Remember, these are general guidelines, and your healthcare professional will determine the most appropriate examinations and tests based on your individual situation.

Treatment Options

The goals of treatment for gigantism (growth hormone excess) are to control the size of the tumor, regulate growth hormone and IGF-1 levels, improve symptoms, and treat the effects of growth hormones on other body systems. Here are the recommended treatments and how they work to achieve these goals:

Surgery: Transsphenoidal surgery is commonly used to remove pituitary tumors causing elevated growth hormone levels. Surgeons enter through the nose to remove the tumor, which lowers growth hormone levels and improves symptoms. If the tumor is not on the pituitary gland, other types of surgery may be necessary.
Medications: Doctors may recommend medications to help normalize growth hormones. Two types of medications commonly used are:
- Somatostatin analogs (SSAs): These drugs signal the pituitary gland to produce less growth hormone and may decrease tumor size.
- Dopamine-receptor agonists: These medications curb growth hormone secretion but are not as effective as SSAs.
Radiation therapy: If surgery is not an option or ineffective, radiation therapy may be recommended. It destroys tumor cells using a beam of radiation.

It's important to note that these treatment options should be discussed with a doctor, as they will determine the best approach based on factors like age, tumor size, symptom severity, and hormone levels. Health behavior changes may also be recommended to manage symptoms and support overall health.

Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Side effects can occur. Check with your health care professional or read the information provided with your medication for side effect information.