growth hormone secreting pituitary adenoma

Growth Hormone Secreting Pituitary Adenoma: An Overview

A growth hormone-secreting pituitary adenoma is a type of tumor that originates in the somatotropic cells of the pituitary gland. This rare condition is characterized by the excessive production of growth hormone (GH), which triggers the liver to produce insulin-like growth factor 1 (IGF-1). IGF-1 plays a crucial role in bone and tissue growth, metabolism, and other bodily processes.

Causes and Symptoms

Growth hormone-secreting pituitary adenomas are typically benign tumors that can cause various physical changes and health issues. The symptoms of this condition depend on the age of the individual:

• In children, excessive GH production leads to gigantism.
• In adults, it results in acromegaly, a rare but serious condition characterized by:
  • Enlargement of hands and feet
  • Gnathopathy (jaw abnormalities) with malocclusion of teeth
  • Soft tissue swelling

Prevalence and Demographics

Growth hormone-secreting adenomas are the second most common functional pituitary tumors, accounting for about 20% of all pituitary adenomas. They predominantly affect adults in their third to fifth decade, with a long subclinical course ranging from 4 to 10 years.

Treatment and Management

The management paradigm for growth hormone-secreting pituitary adenomas involves surgical intervention as the primary treatment option. Radiation therapy may be considered as a second-line treatment in selected patients who have failed transsphenoidal surgery.

References:

• [1] Growth hormone–secreting pituitary adenomas begin in the somatotropic cells of the pituitary gland.
• [2] Management paradigm for growth hormone-secreting pituitary adenomas.
• [3] Growth hormone–secreting adenomas are the second most common functional pituitary tumors (after prolactinomas).
• [4] Somatotroph adenomas make excess growth hormone and cause different symptoms depending on age.
• [5] The majority of patients with acromegaly harbor a functioning growth hormone (GH) pituitary adenoma.

Symptoms of Growth Hormone Secreting Pituitary Adenoma

Growth hormone-secreting pituitary adenomas, also known as somatotroph adenomas, can cause a range of symptoms depending on the age of the individual. In children and teens, high levels of growth hormone can stimulate the growth of nearly all bones in the body, leading to gigantism [1]. This condition is characterized by excessive growth and development, which can result in being very tall.

In adults, these adenomas are a common cause of acromegaly, a rare but serious condition that results from too much growth hormone. Symptoms of acromegaly include:

• An enlarged face and hands
• Changes to the face may cause the brow bone and lower jawbone to protrude [5]
• Unexpected weight gain, easy bruising of the skin, and muscle weakness [8]
• Increased hair growth on the face and body
• A buildup of fat between the shoulders (buffalo hump)

Additionally, high levels of growth hormone can also lead to an increase in insulin-like growth factor-1 (IGF-I) levels, which is a marker for growth hormone excess. This can result in symptoms such as:

• High blood pressure
• Heart palpitations or irregular heartbeat
• Increased appetite and weight gain

It's essential to note that these symptoms can vary widely depending on the size of the tumor and whether it is causing an increase or decrease in hormone production.

References:

[1] Somatotroph adenomas make excess growth hormone (also known as somatotropin) and make up about 2 in 10 pituitary tumors. [3] [5] Symptoms of acromegaly include an enlarged face and hands. Changes to the face may cause the brow bone and lower jawbone to protrude, and the ... [5] [8] Symptoms include unexpected weight gain, easy bruising of the skin and muscle weakness. [8]

Diagnosing Pituitary Tumors

Pituitary tumors can be challenging to diagnose due to their slow growth and similar symptoms to other medical conditions. However, there are several tests that can help identify these tumors.

• Blood Tests: Blood tests can detect abnormal hormone levels in the body, which can indicate a pituitary tumor. For example, a blood test may show high levels of growth hormone (GH), which is often associated with acromegaly or gigantism [1].
• Urine Tests: Urine tests can also detect abnormal hormone levels, such as cortisol, which can be elevated in cases of Cushing's syndrome [7].
• Imaging Tests: Imaging tests like MRI scans and CT scans can help visualize the pituitary gland and identify any tumors or abnormalities. These tests are often used in conjunction with blood and urine tests to confirm a diagnosis [5][8].

Additional Diagnostic Tools

Other diagnostic tools, such as the oral glucose tolerance test (OGTT), may also be used to diagnose pituitary tumors. The OGTT is a test that measures how well the body regulates blood sugar levels after consuming a sugary drink [6]. This test can help confirm a diagnosis of acromegaly or gigantism.

Screening Tests

Screening tests, such as measurement of late-night salivary cortisol levels, may also be used to detect pituitary tumors. These tests are often used in cases where there is a high suspicion of a tumor based on symptoms and physical examination [9].

It's worth noting that diagnosis can take time and may involve multiple tests and evaluations. If you suspect you might have a pituitary tumor, it's essential to consult with a healthcare professional for proper evaluation and treatment.

References:

[1] Context 1 [2] Context 2 [3] Context 3 [4] Context 4 [5] Context 5 [6] Context 6 [7] Context 7 [8] Context 8 [9] Context 9

Treatment Options for Growth Hormone Secreting Pituitary Adenomas

Growth hormone secreting pituitary adenomas can be treated with a variety of medications, which aim to reduce the production of excess growth hormone and shrink the tumor. Here are some of the treatment options:

• Somatostatin analogs: These medications, such as Lanreotide and Octreotide, mimic the action of somatostatin, a natural hormone that inhibits the release of growth hormone. They can decrease growth hormone production and may also reduce the size of the tumor [5].
• Cabergoline: This medication is a dopamine agonist that can normalize insulin-like growth factor 1 (IGF-1) levels in approximately 37% of patients [4]. It works by stimulating the somatotroph cells to produce less growth hormone.
• Pegvisomant: This medication blocks the effect of excess growth hormone on the body, making it a useful treatment option for patients with acromegaly. It is administered via injection every day [7].
• Dopaminergic agonists: These medications, such as bromocriptine and cabergoline, can be used to treat prolactinomas, but they may also be effective in reducing growth hormone production in some cases [8].

Medication Selection

The choice of medication depends on various factors, including the size and type of tumor, the patient's age and overall health, and the presence of any other medical conditions. Your doctor will work with you to determine the best treatment plan for your specific situation.

It is essential to note that these medications may have side effects, and their effectiveness can vary from person to person. Regular monitoring and follow-up appointments with your healthcare provider are crucial to ensure the medication is working effectively and to address any concerns or issues that may arise.

References:

[4] MS Racine · 2002 · Cited by 47 — Cabergoline, the most efficacious dopamine agonist for treating prolactinomas and acromegaly. [5] Lanreotide and Octreotide: Somatostatin analogs for treating growth hormone secreting pituitary adenomas. [7] Pegvisomant (Somavert): A growth hormone receptor antagonist for treating acromegaly. [8] Dopaminergic agonists for treating prolactinomas and other endocrine disorders.

The differential diagnosis of growth hormone-secreting pituitary adenomas involves distinguishing this condition from other causes of excessive growth hormone secretion.

Causes to Consider

• Somatotropinomas: These are tumors that produce excess growth hormone, leading to symptoms similar to those of growth hormone-secreting pituitary adenomas.
• Other diseases with increased growth hormone secretion:
  • Lymphocytic hypophysitis: A rare condition characterized by inflammation of the pituitary gland, which can lead to excessive growth hormone production.
  • Non-pituitary sources of increased growth hormone: These include conditions such as acromegaly caused by a non-pituitary source.

Diagnostic Tests

• Corticotropin-releasing-hormone test: This test is used to differentiate between Cushing's syndrome and other causes of excessive cortisol production.
• High-dose dexamethasone test: This test can help diagnose Cushing's syndrome by suppressing cortisol production in response to high doses of dexamethasone.

Key Points

• Growth hormone-secreting pituitary adenomas are a common cause of acromegaly, a rare but serious condition resulting from too much growth hormone.
• The most common cause of acromegaly is a growth hormone (GH) secreting adenoma in the pituitary gland [6].
• Other conditions, such as somatotropinomas and non-pituitary sources of increased growth hormone, must be considered in the differential diagnosis.

References

[1] The Pituitary Society published guidelines on diagnosis and management of prolactin-secreting adenomas (referred to hereafter as prolactinomas) in 2006 [14]. [2] Testing with cortisol and other hormones is useful in the differential diagnosis of Cushing's syndrome [15]. [3] The corticotropin-releasing-hormone test versus the high-dose dexamethasone test in the differential diagnosis of Cushing's syndrome. Lancet. 1986;2(8506):540–544 [1].