Acromegaly is caused when the pituitary gland produces too much growth hormone. Growth hormone is the substance which stimulates the normal growth of tissues, organs and bones and helps control the body’s metabolism.
In the vast majority of cases, the overproduction of growth hormone is caused by a benign (non-cancerous) growth in the pituitary gland - a small gland about the size of a pea located at the base of the brain.
The tumour, known as a pituitary adenoma, usually occurs spontaneously and is not genetically inherited.
The tumour grows slowly over a period of years so the symptoms of acromegaly are most likely to emerge in middle age.
If tumour starts in childhood, acromegaly can make the bones grow longer than normal, leading to a condition known as gigantism. If the tumour starts in adulthood however, the bones are not able to grow longer, so they become thicker.
Acromegaly can cause gradual changes in physical appearance and general health over several years. Early signs and symptoms may be mistaken for ageing or other common conditions, which can make early diagnosis difficult.
The word Acromegaly is derived from the Greek language to mean ‘large extremities’, as swollen hands and feet are one of the most common symptoms experienced. This swelling of soft tissues, such as hands and feet, often require patients to increase the size of shoes or rings on their fingers. Changes in the bone thickness gradually alters the facial features, causing protrusion of the brow and lower jaw, enlargement of the nasal bone and increased space between the teeth.
Specific symptoms of acromegaly include:
- Enlarged hands and feet - often requiring larger rings or shoe sizes
- A change in the face, jaw or tongue:
- Cheekbones or forehead are more prominent
- Bite has changed (inability to bite) or teeth have become more widely spaced
- Lips and tongue have enlarged causing snoring or dribbling at night
Symptoms that suggest acromegaly:
- Excessive sweating
- Heavy snoring or daytime sleepiness
- Tingling/numbness in both hands (carpal tunnel syndrome)
- Skin becoming more oily, thicker and hairier
Other conditions associated with acromegaly:
- High blood pressure
If you have at least one specific symptom and three or more of the suggestive symptoms and one or more of the associated conditions, visit your doctor and ask for a simple blood test to check for acromegaly. Treatments are available to control the symptoms of acromegaly.
Click here to download a copy of the acromegaly symptom checklist
Acromegaly is rare and is found in approximately 40-60 people in every million - it is estimated that about 1000 people in Australia have the disease.
Acromegaly is most common in people in their 40s and 50s, is equally common in men and women and is found in people of all races.
In most cases, the disease is not inherited.
Because acromegaly develops slowly over many years, it may take some time for the condition to be diagnosed. Often people are aware of subtle changes in their bodies before the signs of acromegaly become obvious. Many symptoms, such as snoring/sleep apnoea and diabetes, may be diagnosed and treated independently for many years before the true cause (acromegaly) is detected.
The diagnosis is confirmed through a series of tests to see how the pituitary gland has changed and how other organs are working.
These can include:
- Blood tests to check the level of hormones that are affected by growth hormone in the blood stream e.g. IGF-1
- A special test to see whether growth hormone levels change when fluid containing sugar is ingested – the amount of growth hormone released from the pituitary gland usually drops with an increase in blood sugar levels
- An MRI or CT scan to check the size of the pituitary gland
- X-rays of the skull and jaw to test for changes in the thickness of bones
- Blood tests to check other hormones produced by the pituitary gland
Early diagnosis and treatment of acromegaly means that symptoms can be managed and prevented leading to a better overall quality of life with a decreased chance of life threatening complications.
Complications associated with acromegaly include; high blood pressure, diabetes, sleep apnoea/snoring, arthritis (joint pain), and carpal tunnel syndrome (tingling/numbness in hands).
The four main aims of the treatment of acromegaly are:
- Reducing the production of growth hormones to normal levels
- Relieving pressure from the pituitary tumour on the optic nerves and surrounding areas of the brain
- Preserving normal pituitary function
- Reversing or improving the symptoms of acromegaly and preventing complications
One or more treatments will generally be used. Your doctor will discuss the most appropriate treatment and will help guide you through the decision-making process.
The main types of treatment are:
Surgery aims to remove the pituitary adenoma without affecting other normal parts of the pituitary gland. Usually, surgery is performed through the nasal passages – through the sphenoid bone and the sphenoid sinus in the base of the skull.
After surgery the pressure on regions of the brain that surround the tumour is relieved and growth hormone levels are reduced.
About 80 per cent of patients with small pituitary adenomas can be completely cured by surgery, although the success rate falls to about 50 per cent when the tumours are larger than 1cm in diameter.
If the surgery is successful, the patient's facial appearance and soft tissue swelling improve within a few days. Growth hormone levels can return to normal within hours of surgery and there can be improvement in some of the symptoms before the patient leaves hospital. However, there is a risk that the tumour can grow back.
Because it’s not always possible to remove all the abnormal tissue in the pituitary, other follow-up treatments might be needed.
See section on Surgery for more information.
Medication can be used to shrink large tumours before or following surgery, or may be used instead of surgery. Certain medication can decrease the secretion of growth hormone, reduce the size of the tumour and help control symptoms.
A number of medications are available including tablets, capsules, monthly injections and daily injections, and your doctor can outline the different options.
See section on Medication for further information.
Radiation is sometimes used as the main treatment for a pituitary adenoma, but also can be combined with surgery and/or medication.
Radiation therapy usually is given every week day for four or five weeks and aims to prevent further growth of the pituitary adenoma.
Radiation therapy is relatively slow to produce any improvement in the symptoms of acromegaly. About 30 per cent of people will have normal levels of growth hormone five years later - this rises to about 60 per cent after 10 years and 72 per cent after 15 years.
There is some risk of damage to other parts of the pituitary gland with both radiation therapy and surgery – and this may interfere with the production of other hormones. If this happens, it may be necessary to take medication to replace the other hormones.
See section on Radiation therapy for further information.
Successful treatment can reverse many of the changes in the patient’s body brought on by acromegaly, but it may not be able to reverse all the changes to the shape and size of the bones.
Patients may need to manage an ongoing program of medication and make special arrangements to maintain their treatment if they are travelling.
Question: What effects will treatment have on me?
Once treatment is successful, the soft tissue of your hands and feet will decrease in size and patients often notice that their facial features gradually return towards normal. This may take some time. Any increase in bone size will revert very slowly and there’s a strong possibility the reversal will not be complete.
Excessive sweating should decrease and sugar diabetes should improve or disappear.
Usually headaches will improve, so will any visual disturbance. If you snored, this should improve.
Other conditions which can be serious but you might not know about, such as blood pressure and heart conditions, can also be treated.
Question: How is my progress monitored?
Your condition will require long-term monitoring which will be shared by your endocrinologist, who specialises in the condition, and your GP. Ideally, your endocrinologist will have access to specialist nurses and radiology, plus a neurosurgeon who is expert in pituitary diseases.
To monitor your progress, you will be asked how your symptoms have changed, in particular whether there has been any change in your ring size and facial appearance. It also is important to have regular blood tests to check your growth hormone levels and the function of the rest of the pituitary gland.
Question: What should I do if I want to travel abroad?
Ask your doctor to write a letter to say that you need to take needles and syringes with you for medical purposes.
Question: Will alcohol cause me any problems?
Moderate alcohol intake should not cause problems, but you should consult your specialist for specific advice.
Question: If I’m taking replacement hormones, can I drink alcohol?
There is no interaction between alcohol and these drugs and you are allowed to drink in moderation. However, you should restrict yourself to one or two units of alcohol a day.
Question: Is a pituitary tumour hereditary?
Only in very exceptional cases (less than 1 per cent).
Question: When can I return to work?
Your doctor or a nurse will arrange for a medical certificate to cover your stay in hospital and you will be advised how long you will be expected to remain off work. This usually depends on your job and whether you are self-employed.
Question: When can I start driving again?
Many people with pituitary conditions find there are no restrictions on their driving (depending on their vision), but you should check with your GP, the motor vehicle licensing authority in your state and your insurance company.
You may find problems with your eyesight, but your doctor or specialist will give you full advice and full visual testing before driving again is recommended.
Question: How will my condition affect my insurance and pensions?
Each case will need to be assessed individually. Every insurance company will have its own practices and you should contact your insurance and pension providers to discuss your case.
You need to persevere and be specific because the people you speak to initially may not be familiar with your condition.
The following papers were used for reference in the sections on acromegaly:
- Acromegaly Diagnosis Patient Research, March 2006. Data on file. Australian Pituitary Foundation
- AACE Acromegaly Guidelines Taskforce. American Association of Clinical Endocrinologists Medical Guidelines for the Clinical Practice for the Diagnosis and Treatment of Acromegaly. Endocrine Practice 2004; 10(3):213-225. (c)
- Colao A et al. Systemic Complications of Acromegaly: Epidemiology, Pathogenesis, and Management. Endocrine Reviews 2004; 25(1):102-152. (c)
- Acromegaly Therapy Consensus Development Panel. Consensus Statement: Benefit Versus Risks of Medical Therapy for Acromegaly. Am J Med 1994; 97(5):468-473. (c)
- Holdaway M, Rajasoorya C. Epidemiology of Acromegaly. Pituitary 1999; 2:29-41. (c)
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