Acromegaly - Causes, Symptoms, Treatment

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Introduction

The endocrine system is composed of diverse organs, known as glands, that include the thyroid, parathyroid, adrenal, pituitary, hypothalamus, thymus, pineal, and pancreas. These glands secrete chemical messengers called hormones that coordinate the various functions in the body. The inadequate or excessive secretion of hormones results in endocrine disorders. The pituitary gland is a small-sized gland located on the underside of the human brain that controls other glands; therefore it is called the master gland. The growth hormone (GH) or somatotropin, is produced by pituitary glands that manage muscle growth, bone length, and height. The hypersecretion of GH leads to acromegaly that deforms the appearance of the body.

What is Acromegaly?

Acromegaly is a rare hormonal disorder that is caused by the continuous hypersecretion of growth hormone (GH) by the pituitary gland. In adulthood, the excessive secretion of GH increases the bone size of the hands, feet, and face. It leads to enlarged hands, feet, and facial deformation.


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Figure. Differences in hand between normal and acromegaly persons

What Are the Causes of Acromegaly?

The pituitary gland releases the excess amount of GH into the blood, it signals the liver to secrete a hormone called insulin-like growth factor-1 (IGF-1). It regulates the growth of bone and other tissues. The higher level of GH triggers the IGF-1 resulting in acromegaly. In adults, acromegaly has been related to tumours such as pituitary tumours and non-pituitary tumours.

Pituitary tumour
Non-pituitary tumour
It is a non-cancerous tumour (adenoma) of the pituitary gland. It secretes the too-much GH hormone causing the symptoms of acromegaly.
It is a tumour developed in areas such as the lungs, pancreas or other areas of the chest. This is a rare case of a tumour.
This tumour is slow-growing and cannot be noticed for a long time. A tumour may grow to a large size that can lead to headache and vision impairment, due to the tumour pressing adjacent areas of the brain.
This tumour releases GH by itself, but most of the time, it secretes growth hormone-releasing hormone (GH-RH), a hormone that triggers the pituitary gland to secrete excess GH.

Acromegaly Symptoms

The symptoms of acromegaly can differ from one to another, but the most common symptoms are enlarged hands and feet. The symptoms are identifiable that can include the following;

  • Enlarged facial features include, including face bone, nose, lips, and tongue

  • Extreme sweating and skin odour

  • Excessive oily, thick and coarse skin

  • Joint pain

  • Headaches

  • Vision impairment

  • Growth of skin tags

  • Deeper voice

  • Fatigue and muscle weakness

  • The gap between the teeth

  • Weight gain

  • Tingling and no sensation in the hands and feet

  • Abnormal hair growth in women

  • Menstrual cycle irregularities

  • Abnormal thyroid hormones that affect weight, hair, and skin

  • Erectile disorder in men

Facts About Acromegaly

  • Acromegaly means enlargement that is related to tumour and growth hormones.

  • It is usually caused by a benign tumour located on the anterior lobe of the pituitary gland known as a pituitary adenoma.

  • It is affected by the middle-aged group and it is not a genetic disorder.

  • If the GH increases in children, it is the condition called gigantism.

  • The serious condition of acromegaly can make a person blind.

  • The treatment is available and it can prevent severe complications.

  • There are only a few people affected with acromegaly in the world because it is a rare disorder.

Acromegaly diagnosis

The symptoms of acromegaly are not visible at an early stage, therefore making it hard to diagnose. The blood tests and imaging test confirms that an individual is affected by acromegaly.

Blood tests

  • IGF test: The GH level in the blood usually fluctuates throughout the lifetime. GH is closely related to the IGF-1 hormone and the IGF levels are more stable throughout the day than GH. Therefore, the blood test is used to measure the amount of IGF hormone in the blood.

  • Oral glucose tolerance test: The glucose tolerance test identifies the reaction of growth hormone levels to blood glucose. The blood can be taken at various intervals after drinking the glucose solution. The sugar in drinks normally reduces the GH level, but if a person has acromegaly, the GH level will not decrease

Imaging tests

The imaging tests are used to identify the location of the tumour and measure the growth of the tumour. There are two imaging tests:

  • Magnetic Resonance Imaging (MRI): An MRI scan is used to view the position and size of the pituitary tumour. The radio waves and magnets are used to get a detailed picture of the internal organs and tissues.

  • Computerised Tomography (CT): CT scan is used as a combination of x-rays and computer technology to get images of the internal organs and tissues if an MRI scan is not supported.

Treatments

Certain treatments prevent the patient from developing long-term complications that may develop from acromegaly. Some of these treatments are

  • Surgery: The treatment depends on the location and size of the tumour. If the tumour is removed completely, only surgery is enough. However, chemotherapy and radiation therapy are needed, if only the part of the tumour is removed during the surgery.

  • Chemotherapy: Medicines and injections are used to manage the hormone levels and improve the symptoms that normalise the body.

  • Radiation therapy: Radiation therapy is carried out when the medications and surgery are not supported to treat acromegaly. It is used by special equipment to pass the radiation beams to the targeted area of the tumour. It can reduce the level of growth hormone, however, it takes several years to get the complete effect.

Conclusion

Acromegaly is a rare hormonal disorder. It is developed by the extreme secretion of growth hormone (GH) from the pituitary gland in adults. It is associated with a non-cancerous tumour known as pituitary adenoma. The tumour triggers the secretion of GH resulting in bone deformation of hands, feet, and face. The symptoms are gradually developing so it is difficult to diagnose at an early stage of the disorder. The two blood tests and oral glucose tolerance tests can be used to identify excessive hormonal secretion. The location and size of the tumour can be diagnosed by using an MRI scan and CT scan. The symptoms of acromegaly can be treated by medications, surgery and radiation therapy to prevent long-term complications.

FAQs

1. How is gigantism related to acromegaly?

Gigantism and acromegaly both are growth hormone (GH) disorders. The extreme production of GH from the pituitary gland leads to hormonal problems. But they have different symptoms.

2. How common is acromegaly and who gets affected?

No, acromegaly is not a common disorder. It is a rare disorder of excessive production of GH affected by middle-aged people.

3. What are the symptoms of acromegaly?

The most common symptoms are enlarged hands and feet. It has other symptoms including joint pain, headaches, vision impairment, growth of skin tags, deeper voice, fatigue, and muscle weakness.

4. What is the glucose tolerance test conducted in acromegaly?

Acromegaly can develop glucose intolerance. The excessive hormone secretion reacts to the blood glucose. The blood can be taken at various intervals after drinking the glucose solution. The sugar in drinks normally reduces the GH level, but if a person has acromegaly then the GH level will not decrease.

5. Define pituitary adenoma.

A pituitary adenoma is a non-cancerous tumour that triggers the extreme secretion of growth hormone that causes acromegaly.

References

  • Acromegaly: Causes, Symptoms, Diagnosis & Treatments. Cleveland Clinic. (2022). Retrieved 19 May 2022, from https://my.clevelandclinic.org

  • Dineen, R., Stewart, P., & Sherlock, M. (2016). Acromegaly – Diagnosis and Clinical Management. QJM, hcw004. https://doi.org

  • Health, N. (2022). Acromegaly | NIDDK. National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved 19 May 2022, from https://www.niddk.nih.gov

raja
Updated on 13-Oct-2022 11:19:47

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