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Acromegaly

life science Maturity 7-9 Next article →

Acromegaly is a medical disorder characterized by the excessive growth of specific body parts. This condition occurs when the body produces too much growth hormone (GH) after the growth plates have already closed. While children with excess GH experience gigantism, which causes extreme height, adults with acromegaly see changes in bone shape and tissue thickness. This disorder is significant because it affects many different systems in the human body. If left untreated, the condition can reduce life expectancy by 10 years. However, with successful medical intervention, life expectancy can return to that of the general population.

Acromegaly growth hormone levels
Acromegaly growth hormone levels

Most cases of acromegaly, about 98 percent, are caused by a pituitary adenoma. An adenoma is a benign, or non-cancerous, tumor located on the pituitary gland in the brain. This tumor causes the overproduction of growth hormone. As the adenoma grows, it can physically press against surrounding brain tissues. This pressure often leads to headaches or visual disturbances. In some instances, the tumor may compress the optic chiasm, which is a part of the visual system. This compression causes specific problems with a person's vision.

Acromegaly pituitary macroadenoma
Acromegaly pituitary macroadenoma

The mechanism behind these tumors often involves a somatic mutation. This is a genetic change that happens in a single pituitary cell during a person's life. These mutations are not present at birth and are not typically inherited from parents. The mutation occurs in a gene that manages chemical signals within the cells. This error permanently switches on the signal that tells the cell to divide and secrete GH. Some adenomas grow very slowly, meaning symptoms might not appear for many years. Other tumors grow aggressively and may invade the sinuses or nearby brain areas.

Acromegaly presents through a wide variety of physical symptoms. The most common initial sign is the enlargement of the hands and feet. Other visible changes include a larger nose, lips, and ears. The face may change as the forehead, jaw, and skull expand. This can lead to facial features like a protruding lower jaw, known as prognathism, or a protruding brow, called frontal bossing. Internal changes also occur, such as the swelling of the heart and kidneys. The vocal cords may thicken, which results in a deeper voice and slower speech patterns.

Acromegaly treatment diagram
Acromegaly treatment diagram

Because the hormone affects so many tissues, several complications can arise. Many patients develop hypertension, which is high blood pressure, affecting about 40 percent of cases. Diabetes mellitus is another common complication. The disease can also lead to sleep apnea, a condition where breathing stops and starts during sleep. This specific issue affects around 70 percent of patients and often does not resolve even after hormone levels are controlled. Other serious risks include cardiomyopathy, which is a weakening of the heart muscle, and an increased risk of colorectal cancer.

Doctors diagnose acromegaly by measuring GH and insulin-like growth factor I (IGF-1) in the blood. In healthy individuals, GH levels fluctuate and often reach undetectable levels. In people with acromegaly, the secretion is continuous, so levels remain high. An MRI of the brain is used to locate the tumor and see its effect on the pituitary gland. Physicians may also use a glucose test to see how GH levels react to sugar. This helps confirm if the hormone production is truly out of control.

Treatment focuses on lowering GH levels and removing the tumor. Surgery is usually the first choice for treatment. One common method is endonasal transsphenoidal surgery, where the surgeon reaches the tumor through the nose. This is less invasive than older methods and has a faster recovery time. Surgery is most successful when the tumor is no larger than 10 mm in diameter. If surgery is not possible, doctors use medications like somatostatin analogues. These drugs can help shrink tumors or inhibit hormone release. Another option is radiation therapy, which is often used if tumors remain after surgery.

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File:Acromegaly growth hormone levels.JPEG
Acromegaly growth hormone levels.JPEG
File:Acromegaly pituitary macroadenoma.JPEG
Acromegaly pituitary macroadenoma.JPEG
File:Acromegaly treatment diagram.JPEG
Acromegaly treatment diagram.JPEG
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