Advik Singh
Acromegaly is a rare but serious medical disorder that can profoundly affect an individual’s quality of life. It occurs when the body produces too much growth hormone (GH) over a prolonged period, leading to abnormal growth of bones and tissues. Most commonly, this overproduction is caused by a benign tumour in the pituitary gland, a small structure at the base of the brain that plays an important role in controlling hormone levels.
In this article, we will explore how pituitary tumours lead to acromegaly, the impact they have on hormone levels, and the treatment options available to manage the condition.
The pituitary gland is commonly called the "master gland" due to its key role in controlling the body’s endocrine system. Despite its small size, it regulates vital hormones that affect growth, metabolism, reproduction, and more.
But what exactly does this gland do, and why is it so essential? Here’s an overview of its key functions:
Pituitary Gland Structure: The pituitary is divided into two parts: the anterior lobe and the posterior lobe. The anterior lobe produces several hormones, including growth hormone (GH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), and prolactin. The posterior lobe releases hormones like oxytocin and vasopressin (antidiuretic hormone, ADH).
Hormonal Regulation: The hypothalamus, a part of the brain, controls the production and release of hormones from the pituitary. It sends signals to the pituitary to either release or stop the release of hormones, maintaining the body’s hormonal balance.
Pituitary Tumours and Hormonal Imbalance: Tumours in the pituitary gland can disrupt the regulation of hormones, leading to either an overproduction or underproduction of key hormones, such as growth hormone (GH). This imbalance can result in conditions like acromegaly (caused by excess GH) or hypopituitarism (due to insufficient hormone production).
Acromegaly occurs when a pituitary tumour causes excessive production of growth hormone (GH). But how does this happen, and what are the effects? Here’s the explanation:
Pituitary Adenomas: Most acromegaly cases are caused by benign tumours in the pituitary gland called pituitary adenomas. These tumours release excess GH, disrupting normal hormone regulation.
Increased IGF-1: Elevated GH stimulates the liver to produce more insulin-like growth factor 1 (IGF-1), which promotes tissue and bone growth.
Symptoms: The symptoms of acromegaly include enlarged hands and feet, coarse facial features, thickened skin, joint pain, sleep apnea, and increased sweating.
Acromegaly is primarily caused by the overproduction of growth hormone (GH), but the condition can also disrupt several other hormone levels in the body.
This leads to a complex imbalance within the endocrine system, impacting multiple hormones and causing a wide range of effects. Here’s how acromegaly affects different hormones:
1. Growth Hormone (GH) and IGF-1: The excessive release of GH stimulates the liver to produce more insulin-like growth factor 1 (IGF-1), which promotes tissue growth. High IGF-1 levels are a key diagnostic marker of acromegaly and contribute to abnormal growth in bones and tissues, especially in the hands, feet, and face.
2. Thyroid Hormones: Elevated GH levels can affect thyroid function by influencing thyroid-stimulating hormone (TSH) production. This may result in hypothyroidism or other thyroid issues, further complicating the management of acromegaly.
3. Cortisol and Adrenal Function: Acromegaly can affect adrenal glands by increasing adrenocorticotropic hormone (ACTH) secretion, which regulates cortisol. Excess cortisol can lead to symptoms such as weight gain, high blood pressure, and diabetes.
4. Sex Hormones: Changes in sex hormone levels, including oestrogen and testosterone, can occur in acromegaly, leading to menstrual irregularities in women and sexual dysfunction in men. These disruptions can cause a range of additional symptoms beyond the physical changes typically seen in the condition.
Diagnosis of acromegaly involves the following steps:
Blood Tests: Elevated IGF-1 levels and an oral glucose tolerance test (GH levels do not decrease after glucose intake) confirm the diagnosis.
Imaging: MRI scans detect and assess the size of pituitary tumours to guide treatment.
The treatment of acromegaly generally focuses on reducing the size of the pituitary tumour and normalising hormone levels. Common treatment options include:
1. Surgery: The most common approach to treating acromegaly is through surgery to remove the pituitary adenoma. Transsphenoidal surgery, which involves accessing the tumour through the nose, is often used to remove the tumour while preserving surrounding healthy tissue.
2. Radiotherapy: If surgery is not possible or does not completely remove the tumour, radiotherapy may be recommended. This treatment involves using targeted radiation to shrink the tumour and reduce GH production.
3. Medications: Several medications are available to help control GH levels and manage acromegaly. One of the most commonly used medications is Octreotide, which is a synthetic version of somatostatin, a hormone that inhibits the release of growth hormone. Sandostatin used for reducing GH levels and to shrink the pituitary tumour in many patients with acromegaly.
These medications can help control the overproduction of growth hormone, particularly when surgery and radiotherapy are not sufficient.
4. Dopamine Agonists: Another medication option is dopamine agonists, which can reduce GH secretion in some patients.
5. GH Receptor Antagonists: In some cases, medications like pegvisomant can block the effects of growth hormone at the tissue level, offering another treatment option.
Pituitary tumours causing acromegaly lead to excessive growth hormone production, affecting tissues and organs. This disruption can result in significant physical changes and hormone imbalances. Early diagnosis and treatments like surgery, radiotherapy, and medications can manage the condition, preventing complications and improving quality of life.
Proper treatment helps control hormone levels and alleviate symptoms. With timely intervention, individuals can lead normal, fulfilling lives.
