Understanding Abnormal Growth: Acromegaly and Gigantism
Abnormal and continuous growth is a key symptom of two rare, but distinct, endocrine disorders: acromegaly and gigantism. Both conditions stem from an overproduction of growth hormone (GH), a crucial hormone secreted by the pituitary gland. The main difference between them lies in when the excess GH is produced relative to puberty and the fusion of a person's growth plates, or epiphyseal plates.
When excess GH production begins in childhood, before the growth plates have fused, it results in gigantism, causing a person to grow unusually tall. In contrast, acromegaly develops in adults after the growth plates have closed, meaning height is unaffected. Instead, bones in the face, hands, and feet enlarge, and internal organs can increase in size.
The Pituitary Gland and the Root Cause
In the vast majority of cases, the source of excess growth hormone is a benign, or noncancerous, tumor on the pituitary gland, called a pituitary adenoma. This pea-sized gland at the base of the brain is responsible for producing several important hormones, including GH. The adenoma causes the gland to secrete excessive amounts of GH into the bloodstream.
This elevated level of GH, in turn, signals the liver to produce an excess of insulin-like growth factor-1 (IGF-1), which is the hormone primarily responsible for driving the growth of bones, cartilage, and other tissues. The slow growth of these benign tumors often means that symptoms develop gradually over many years, which can delay diagnosis. In rare instances, tumors in other parts of the body, such as the pancreas or lungs, can also produce hormones that trigger excess GH production.
Comparing Gigantism and Acromegaly
The age of onset is the defining factor that differentiates these two conditions. In children with gigantism, the epiphyseal plates at the end of long bones are still open, allowing for significant linear growth. Once puberty is complete, these growth plates fuse, and the individual can no longer grow taller. For adults with acromegaly, the fused growth plates prevent further height increases, forcing bone growth to occur in other areas and resulting in distinct features.
| Feature | Gigantism | Acromegaly |
|---|---|---|
| Onset | Childhood or adolescence | Adulthood |
| Effect on Height | Unusually tall stature | No change in height |
| Growth Location | Long bones, leading to tallness | Bones of face, hands, feet; internal organs |
| Key Symptoms | Rapid growth, delayed puberty, prominent jaw and forehead | Enlarged hands/feet, facial changes, joint pain |
| Growth Plates | Open and unfused | Fused |
| Diagnosis Often Occurs | Younger age | Middle age (40s-50s) |
Signs, Symptoms, and Complications
Because the excess growth hormone affects bones, soft tissues, and organs throughout the body, both conditions present a range of symptoms. Since acromegaly develops slowly, patients may not notice changes for years.
- Visible Physical Changes: Enlarged hands and feet (requiring larger shoe or ring sizes), thickened, coarse, and oily skin, enlargement of facial features (nose, lips, tongue), and widening spaces between teeth.
- Musculoskeletal Issues: Joint aches and arthritis, carpal tunnel syndrome, and muscle weakness.
- Systemic Symptoms: Excessive sweating and body odor, headaches, fatigue, and deepened voice.
- Organ Enlargement: Excessive GH can cause the heart and other organs to enlarge, leading to significant health risks if untreated.
Untreated acromegaly and gigantism can lead to serious health complications, such as heart disease (including an enlarged heart), high blood pressure, type 2 diabetes, sleep apnea, vision problems, and an increased risk of colon polyps.
Diagnosis and Treatment
Diagnosis typically begins with a thorough physical examination and an assessment of a patient's medical history. Blood tests are essential for confirming the condition. A blood sample is taken to measure levels of IGF-1, as high levels are often an indicator of acromegaly or gigantism. A definitive diagnosis is often confirmed with an oral glucose tolerance test (OGTT). Normally, a sugary drink suppresses GH levels, but in patients with these conditions, the levels remain high. An MRI is then used to locate and assess the size of any potential pituitary tumor.
The goal of treatment is to return GH and IGF-1 levels to normal and reduce the tumor's size. Treatment options include:
- Surgery: The most common approach is transsphenoidal surgery, where a neurosurgeon removes the tumor through an incision made through the nose and sphenoid sinus. This can often be curative, especially for smaller tumors.
- Medication: If surgery isn't possible or fails to normalize hormone levels, medications can be used. These include somatostatin analogs to suppress GH release, dopamine agonists, and GH-receptor antagonists that block GH's effects.
- Radiation Therapy: High-energy radiation can be used to destroy tumor cells, especially when surgery is not fully successful. This process can be slow and may take several years to normalize hormone levels.
Early diagnosis and consistent treatment are crucial for preventing the long-term complications associated with acromegaly and gigantism, improving symptoms, and normalizing life expectancy. For comprehensive information on endocrine disorders, refer to authoritative sources like the National Institute of Diabetes and Digestive and Kidney Diseases.
Conclusion
The medical condition for which you continue to grow is a result of excess growth hormone, caused by a pituitary tumor. If this occurs in childhood, it is known as gigantism, leading to excessive height. If it develops in adulthood, it's called acromegaly, causing bone and organ enlargement without increasing height. While these conditions can be serious, an early and accurate diagnosis, followed by a multi-faceted treatment plan, can effectively manage the symptoms and mitigate the long-term health risks associated with excessive growth hormone production.
