Acromegaly is a rare hormonal disorder arising when the body produces an excess of growth hormone (GH) in adulthood. This condition affects various body tissues and bones, causing them to grow in irregular ways. Early identification and management are important to prevent potential health complications.
The Cause of Excessive Growth Hormone
The overproduction of growth hormone typically originates from the pituitary gland, a small, pea-sized gland located at the base of the brain. In the vast majority of cases, a benign (non-cancerous) tumor known as a pituitary adenoma develops on this gland. This tumor then causes the pituitary gland to release excessive amounts of growth hormone into the bloodstream.
When high levels of growth hormone circulate, they signal the liver to produce another hormone called insulin-like growth factor 1 (IGF-1). IGF-1 is the primary hormone directly responsible for stimulating the growth of bones, cartilage, and other body tissues. Elevated IGF-1 levels also influence how the body processes blood sugar and fats, contributing to broader systemic effects.
Recognizing the Symptoms of Acromegaly
The signs and symptoms of acromegaly typically develop gradually, often over several years, which can lead to delays in diagnosis. Individuals may observe an enlargement of their hands and feet, sometimes requiring changes in shoe or ring sizes. Facial features can also become more pronounced, including a jutting jaw, a broader nose, and thicker lips and ears.
Beyond external changes, acromegaly can affect internal systems and overall well-being. Many people experience joint pain and stiffness, which can progress to arthritis. Skin may become thicker, oilier, and exhibit excessive sweating. Other common symptoms include a deepening of the voice, fatigue, and headaches. Sleep apnea, a condition where breathing repeatedly stops and starts during sleep, is also frequently associated with acromegaly.
The Diagnostic Process
Confirming a diagnosis of acromegaly involves specific tests designed to measure hormone levels and visualize the pituitary gland. Blood tests are a primary diagnostic tool, specifically measuring insulin-like growth factor 1 (IGF-1). Persistently elevated IGF-1 levels are a strong indicator. A growth hormone suppression test, also known as an oral glucose tolerance test, is often performed. During this test, an individual drinks a glucose solution, and growth hormone levels are measured; in healthy individuals, glucose suppresses GH levels, but in those with acromegaly, GH levels remain high.
Once blood tests suggest acromegaly, imaging is typically used to locate and assess the pituitary gland. Magnetic Resonance Imaging (MRI) of the brain is the standard imaging technique. An MRI can effectively visualize the pituitary gland, confirming the presence of a tumor (adenoma) and determining its size and location.
Treatment Approaches for Acromegaly
Treatment for acromegaly aims to normalize growth hormone and IGF-1 levels, alleviate pressure caused by the pituitary tumor, and manage associated symptoms. The most common initial treatment is surgery, specifically a procedure called transsphenoidal surgery. In this procedure, surgeons typically remove the pituitary tumor through the nasal cavity or an incision under the upper lip, offering a direct path to the gland.
If surgery does not fully normalize hormone levels, or if it is not a suitable option, medication can be used to lower GH and IGF-1. These medications may include somatostatin analogs, which reduce GH secretion, or growth hormone receptor antagonists, which block the action of GH on tissues. Radiation therapy is another treatment option, often considered after surgery or in conjunction with medication. Radiation works by slowly shrinking the tumor and reducing growth hormone production.