Definition

Acromegaly is a rare disorder characterized by the excessive production of growth hormone, which leads to the accelerated growth of body tissues and bones.

While typically diagnosed in adults between the ages of 30 and 50, acromegaly can occur at any age. When this condition develops before puberty ends, it is referred to as gigantism.

Causes

Acromegaly results from an overproduction of growth hormone by the pituitary gland, a small gland located at the base of the brain.

This excessive hormone production is usually caused by a benign, noncancerous tumor known as an adenoma in the pituitary gland.

The majority of acromegaly symptoms stem from the overproduction of growth hormone; however, some symptoms, such as headaches and vision disturbances, may arise from the tumor compressing adjacent tissues, including nearby nerves.

Adenomas typically form spontaneously due to genetic mutations in pituitary cells. These mutations trigger uncontrolled cell growth, leading to tumor formation.

In rare cases, acromegaly can be the result of a tumor located elsewhere in the body, such as in the lungs, pancreas, or other parts of the brain. Certain genetic conditions may also be associated with the development of acromegaly.

Risk Factors

Acromegaly is most commonly diagnosed in adults of middle to older age. Although the condition may sometimes run in families, a hereditary cause is rare, with most cases not being inherited.

Symptoms

Acromegaly presents with a range of symptoms, which typically develop gradually. Early signs may include:

• Swollen hands and feet, with noticeable changes in ring or shoe sizes
• Fatigue, sleep disturbances, and sometimes obstructive sleep apnea
• Gradual alterations in facial features, such as enlarged eyebrows, lower jaw, or nose, and increased spacing between teeth
• Numbness and weakness in the hands, often due to carpal tunnel syndrome

In children and adolescents, acromegaly may manifest as excessive growth in height.

As the condition progresses, more common symptoms may include:

• Abnormally large hands and feet
• Enlarged and prominent facial features, including the nose, lips, and tongue
• Skin changes, such as thickening, roughness, oiliness, skin tags, and excessive sweating
• Joint pain
• Fatigue and muscle weakness
• Headaches
• Blurred or impaired vision
• Decreased libido
• Irregular menstrual cycles in women and erectile dysfunction in men

These symptoms typically become more pronounced with age.

Diagnosis

To diagnose acromegaly, a blood test measuring growth hormone levels is typically performed.

For accurate test results, you will be asked to consume a sugary liquid before your blood is drawn. In individuals without acromegaly, this liquid suppresses growth hormone release; however, in those with acromegaly, blood growth hormone levels remain elevated, a finding confirmed by the glucose tolerance test.

Your doctor will also assess other hormone levels, including insulin-like growth factor 1 (IGF-1). Elevated IGF-1 is a strong indicator of acromegaly.

If blood tests reveal elevated growth hormone and IGF-1 levels, an MRI scan of your brain may be conducted to locate and assess the size of the pituitary adenoma. Although a CT scan can be performed, it is less precise than MRI for this purpose.

Management

The approach to treating acromegaly depends on the individual's symptoms. The primary goals of treatment are to:

• Normalize growth hormone production
• Relieve the pressure exerted by the tumor on surrounding tissues
• Address any hormonal deficiencies
• Alleviate symptoms

Most patients with acromegaly undergo surgery to remove the tumor. In some cases, medication or radiation therapy may be used either in place of or in addition to surgery.

Surgery is typically effective and can potentially cure acromegaly. However, if the tumor is too large to be fully removed, additional surgery or further treatment with medication or radiation may be necessary.

During the procedure, which is performed under general anesthesia, the surgeon makes a small incision either inside the nose or behind the upper lip to access the pituitary gland.

A thin, flexible tube equipped with a light and video camera, called an endoscope, is inserted through the incision to provide visualization of the tumor. Surgical instruments are also inserted through the same incision to remove the tumor.

Once the tumor is removed, growth hormone levels will immediately decrease, and the pressure on surrounding tissues will be relieved. Facial features may return to normal, and swelling typically improves within a few days.

Although surgery is generally safe, it carries some risks, including:

• Damage to healthy portions of the pituitary gland
• Leakage of cerebrospinal fluid
• Meningitis, though rare

Your doctor will discuss these potential risks with you.

If surgery does not fully normalize growth hormone levels or is not an option, medication may be prescribed.

There are three main types of medications:

• Monthly injections of octreotide, lanreotide, or pasireotide, which reduce growth hormone production and may shrink the tumor.
• Daily injections of pegvisomant, which block the effects of growth hormone and can greatly improve symptoms.
• Oral tablets of bromocriptine or cabergoline, which inhibit growth hormone production but are effective in only a small number of cases.

Each medication has its own advantages and drawbacks, and your doctor will discuss the most appropriate options for you, along with potential benefits and risks.

If surgery is not feasible, if complete tumor removal is not achieved, or if medications prove ineffective, your doctor may recommend radiation therapy.

Radiation therapy can reduce growth hormone levels, but its effects may take several years to manifest, requiring continued medication use during this period.

There are two types of radiation therapy for acromegaly:

• Stereotactic radiotherapy: a high-dose, precise beam of radiation is directed at the adenoma.
• Conventional radiotherapy: a broader, less targeted beam of radiation is directed at the adenoma, which can result in damage to the pituitary gland and surrounding brain tissue.

Complications

Untreated acromegaly can lead to several complications, including:

• Type 2 diabetes
• Hypertension
• Heart disease
• Cardiomyopathy
• Joint inflammation
• Bowel polyps, which may become cancerous if left untreated

Due to the risk of bowel polyps, a colonoscopy may be recommended if you are diagnosed with acromegaly, and regular colonoscopic screening may be necessary.

Prevention

Currently, there is no known way to prevent acromegaly. The exact cause of pituitary tumors is unclear, though genetic factors are thought to play a role.

When to See a Doctor?

If you suspect you have acromegaly, it is crucial to consult a doctor promptly. Acromegaly generally responds well to treatment, but early diagnosis and intervention are important to prevent the progression of symptoms and lower the risk of complications.

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