Gigantism: Symptoms, Causes, Treatment

What are the symptoms of gigantism?

Gigantism is a rare condition that occurs when the body produces too much growth hormone during childhood, before the growth plates in the bones have closed. This excessive growth hormone production leads to abnormal growth and development, resulting in a person being significantly taller than average. Symptoms of gigantism can include:

1. Excessive Growth: The most noticeable symptom of gigantism is excessive growth, usually starting in childhood or adolescence. Children with gigantism may grow much taller than their peers and continue to grow taller even after their peers have stopped growing.
2. Large Hands and Feet: People with gigantism often have disproportionately large hands and feet compared to the rest of their body.
3. Facial Changes: Gigantism can cause changes in facial features, including a prominent jaw, a protruding forehead, and a larger nose and lips.
4. Joint Pain: The rapid growth associated with gigantism can lead to joint pain, especially in the knees and hips.
5. Increased Sweating: Some people with gigantism may experience excessive sweating, especially at night.
6. Delayed Puberty: In some cases, gigantism can delay the onset of puberty or cause irregular menstrual periods in girls.
7. Enlarged Organs: Excessive growth hormone can cause organs such as the heart, liver, and kidneys to enlarge, which can lead to complications.
8. Vision Problems: In rare cases, gigantism can cause vision problems due to pressure on the optic nerves.

What are the causes of gigantism?

Gigantism is primarily caused by an overproduction of growth hormone (GH) during childhood and adolescence, before the growth plates in the bones have closed. The excess GH is usually produced by a noncancerous tumor of the pituitary gland called a pituitary adenoma. This tumor causes the pituitary gland to produce too much GH, leading to abnormal growth and development. In some cases, gigantism can also be caused by other conditions that affect the production of GH or the sensitivity of tissues to GH. These include:

1. Pituitary Adenoma: The most common cause of gigantism is a pituitary adenoma, a benign tumor of the pituitary gland that produces excessive GH.
2. Genetic Mutations: Rare genetic mutations can cause conditions that lead to gigantism, such as multiple endocrine neoplasia type 1 (MEN1) or McCune-Albright syndrome.
3. Carney Complex: Carney complex is a rare genetic disorder that can cause gigantism, as well as other symptoms such as skin pigmentation abnormalities and cardiac myxomas.
4. Familial Isolated Pituitary Adenoma (FIPA): Some cases of pituitary adenomas and gigantism are familial, meaning they run in families. FIPA is a rare genetic condition associated with pituitary adenomas.
5. Acromegaly: While acromegaly typically occurs in adults, if it develops before the closure of the growth plates in adolescence, it can lead to gigantism.
6. Other Conditions: Certain rare conditions or syndromes, such as neurofibromatosis type 1 and Proteus syndrome, can be associated with gigantism.

In most cases, gigantism is caused by a pituitary adenoma and is not inherited. However, in some cases, there may be a genetic component or a familial predisposition to developing pituitary adenomas.

How is the diagnosis of gigantism made?

The diagnosis of gigantism involves a combination of medical history, physical examination, and laboratory tests. Here’s an overview of the diagnostic process:

1. Medical History: Your healthcare provider will ask about your symptoms, growth history, and family history of pituitary disorders or other medical conditions.
2. Physical Examination: A thorough physical examination will be performed to assess your height, weight, and body proportions. Your healthcare provider will also look for signs of gigantism, such as enlarged hands and feet, facial features characteristic of acromegaly (a condition related to gigantism that occurs in adults), and other physical abnormalities.
3. Hormone Testing: Blood tests will be done to measure the levels of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) in your blood. Elevated levels of these hormones are indicative of gigantism.
4. Imaging Studies: Imaging studies, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans, may be done to visualize the pituitary gland and look for the presence of a pituitary adenoma or other abnormalities.
5. Oral Glucose Tolerance Test (OGTT): In some cases, an OGTT may be performed to help differentiate between gigantism and other conditions that can cause elevated GH levels. During this test, blood samples are taken before and after drinking a glucose solution to see how your body responds.
6. Genetic Testing: Genetic testing may be recommended if there is a suspicion of a genetic cause of gigantism, such as multiple endocrine neoplasia type 1 (MEN1) or other genetic syndromes associated with pituitary adenomas.

The diagnosis of gigantism can be complex and may require the expertise of an endocrinologist, a healthcare provider who specializes in hormone-related disorders. Prompt and accurate diagnosis is important to begin appropriate treatment and prevent complications associated with gigantism.

What is the treatment for gigantism?

The treatment for gigantism aims to reduce the production of growth hormone (GH), normalize growth, and prevent complications associated with the condition. The main treatment options for gigantism include:

1. Surgery: The primary treatment for gigantism caused by a pituitary adenoma is surgery to remove the tumor. The surgical approach may be transsphenoidal, where the tumor is accessed through the nose and sinuses, or craniotomy, where a portion of the skull is removed to access the tumor. Surgery is often successful in reducing GH levels and normalizing growth in many cases.
2. Medications: In some cases, medications may be used to reduce GH levels before surgery or as a primary treatment for those who are not candidates for surgery. Medications that may be used include somatostatin analogs (e.g., octreotide, lanreotide) and growth hormone receptor antagonists (e.g., pegvisomant).
3. Radiation Therapy: Radiation therapy may be used if surgery and medications are not effective in reducing GH levels or if the tumor cannot be completely removed. Radiation therapy uses high-energy X-rays or other forms of radiation to destroy tumor cells.
4. Follow-Up Care: After treatment, regular follow-up care is important to monitor GH levels, growth, and any potential complications. Additional treatments or adjustments to treatment may be needed based on follow-up assessments.

It’s important to work closely with a healthcare team experienced in treating gigantism, which may include endocrinologists, neurosurgeons, and radiation oncologists. Treatment plans are individualized based on the specific circumstances of each case, and the goal is to achieve normal growth and development while minimizing the risk of long-term complications.