Acromegaly
What is acromegaly?
Acromegaly is a rare hormonal condition caused by the body being exposed to too much growth hormone (GH) over a prolonged period.
In most people, acromegaly is caused by a non-cancerous tumour of the pituitary gland that produces excessive amounts of growth hormone. These tumours are commonly referred to as pituitary adenomas and may also be described as pituitary neuroendocrine tumours (PitNETs).
Growth hormone acts on many tissues throughout the body. One of its main effects is to stimulate the liver to produce insulin-like growth factor 1 (IGF-1). IGF-1 is responsible for many of the growth-promoting effects associated with excess growth hormone.
Because acromegaly usually develops gradually, physical and other symptoms may appear slowly over many years. Changes can include enlargement of the hands and feet, changes in facial appearance, headaches, increased sweating, joint problems and sleep apnoea.
Acromegaly can affect many different organs and body systems. Early diagnosis and effective treatment are important because controlling excess GH and IGF-1 can reduce symptoms and help prevent or manage complications.
How common is acromegaly?
Acromegaly is a rare condition.
There is currently no publicly available national registry providing comprehensive population-level information about people living with acromegaly in Ireland. As a result, it is difficult to give a precise Irish figure for how many people have the condition.
International studies suggest that approximately 0.2–1.1 people per 100,000 are diagnosed with acromegaly each year, with a pooled estimate of approximately 0.38 cases per 100,000 people per year. The condition is therefore uncommon, but it is likely that some people remain undiagnosed for a considerable period of time.
The number of people living with acromegaly is higher than the number diagnosed each year because it is a chronic condition and people may live with it for many years. Studies have reported prevalence estimates ranging from approximately 3 to 14 cases per 100,000 people, depending on the population studied.
Why can diagnosis take so long?
Acromegaly often develops very slowly. Changes may be so gradual that the person affected, and even their family and friends, may not recognise them.
Some symptoms can also be attributed to more common conditions, such as arthritis, sleep apnoea, headaches or diabetes.
As a result, some people may have acromegaly for several years before it is diagnosed.
Is acromegaly inherited?
In most cases, acromegaly is not inherited and occurs sporadically.
Rare genetic conditions can increase the risk of developing pituitary tumours or acromegaly. These include conditions such as multiple endocrine neoplasia type 1 (MEN1) and familial isolated pituitary adenoma (FIPA).
If there is a significant family history of pituitary tumours or related endocrine conditions, your endocrinologist may recommend specialist genetic assessment.
Is acromegaly the same as gigantism?
No. Acromegaly and gigantism are related conditions caused by excess growth hormone, but they occur at different stages of life.
Acromegaly occurs after the growth plates in the bones have closed, usually in adulthood. Excess growth hormone therefore causes enlargement and thickening of bones and soft tissues rather than increased height.
Gigantism occurs when excessive growth hormone develops during childhood or adolescence, before the growth plates have closed. This can cause excessive linear growth and very tall stature. Gigantism is extremely rare
What causes acromegaly?
In approximately the vast majority of cases, acromegaly is caused by a growth-hormone-producing tumour of the pituitary gland.
Pituitary tumours are usually benign and do not spread to other parts of the body like cancer.
You may hear healthcare professionals use different terms when discussing a pituitary tumour, including:
- Pituitary adenoma
- Growth hormone-secreting pituitary adenoma
- Pituitary neuroendocrine tumour (PitNET)
- Somatotroph PitNET
These terms may be used in different clinical or pathology settings. The terminology used can depend on the specialist and the way the tumour has been classified.
Very rarely, excess growth hormone can arise from a source outside the pituitary gland.
What are the symptoms of acromegaly?
The symptoms of acromegaly can develop gradually and vary considerably from person to person. You may not experience all of the symptoms listed below.
Possible symptoms and signs include:
- Enlargement of the hands and feet
- Increasing ring, glove or shoe size
- Swelling or thickening of the fingers and toes
- Changes in facial appearance
- Enlargement of the nose, lips or tongue
- A more prominent brow or lower jaw
- Increasing gaps between the teeth
- Changes in the way the teeth meet when biting
- Headaches
- Facial pain or pressure
- Excessive sweating
- Increased or changed body odour
- Tiredness and reduced energy
- Sleep problems
- Loud snoring or obstructive sleep apnoea
- Joint pain and stiffness
- Arthritis or worsening joint problems
- Numbness, tingling or weakness in the hands, including carpal tunnel syndrome
- Changes in vision
- Changes in hearing
- A deeper or altered voice
- Changes in speech
- Reduced sex drive
- Erectile dysfunction
- Changes in menstrual periods
- Weight gain
- Mood changes
Acromegaly can also affect internal organs and other body systems. The heart, lungs and other organs can be affected, while complications can include high blood pressure, diabetes, cardiovascular disease, sleep apnoea and joint disease.
Not everyone with acromegaly will experience the same symptoms.
Why does acromegaly cause changes to the face, hands and feet?
Excess growth hormone and IGF-1 stimulate the growth of bones and soft tissues.
In adults, the long bones can no longer increase in length because their growth plates have closed. However, bones can become thicker and soft tissues can enlarge.
This can cause:
- Larger hands and feet
- A broader or more prominent jaw
- A larger nose and lips
- A more prominent brow
- Changes in the spacing of the teeth
- Changes in the shape of the face
- A larger tongue
Because these changes happen gradually, people may not recognise them themselves.
How is acromegaly diagnosed?
Diagnosing acromegaly can sometimes take time because symptoms develop gradually and may resemble those of other conditions.
If you are concerned that you may have symptoms of acromegaly, speak with your GP.
Your GP may arrange initial blood tests and, if acromegaly is suspected, refer you to an endocrinologist, a doctor specialising in hormone and endocrine disorders.
Photographs from several years earlier can sometimes be useful because they may show gradual changes in facial appearance that are difficult to recognise day to day.
What tests are used to diagnose acromegaly?
IGF-1 blood test
The IGF-1 blood test is one of the most important initial tests when acromegaly is suspected.
Unlike growth hormone, which is released in pulses throughout the day, IGF-1 levels are more stable and are therefore particularly useful when assessing possible acromegaly.
IGF-1 levels are interpreted according to factors such as age and the laboratory's reference range.
Current international consensus recommendations place significant importance on IGF-1 measurement when diagnosing acromegaly. (PubMed)
Growth hormone testing
Growth hormone is released in pulses, meaning that a single random GH measurement is generally not sufficient on its own to diagnose or exclude acromegaly.
Your endocrinologist may arrange additional testing depending on your IGF-1 result and clinical circumstances.
Oral glucose tolerance test (OGTT)
An oral glucose tolerance test may be used when the diagnosis remains uncertain.
You will drink a glucose-containing solution and have blood samples taken at specific intervals.
Normally, an increase in blood glucose suppresses growth hormone secretion. In people with acromegaly, GH does not suppress appropriately.
The interpretation of the test depends on the laboratory assay and current clinical criteria.
MRI scan of the pituitary gland
Once biochemical testing supports a diagnosis of acromegaly, an MRI scan of the pituitary gland is usually performed.
An MRI can show whether there is a pituitary tumour and provide information about its size and location.
Most people with acromegaly have a pituitary tumour, although a very small tumour may not always be visible on an MRI.
Visual field testing
The pituitary gland is located close to the optic nerves and optic chiasm.
If a pituitary tumour is close to or pressing on these structures, it can affect peripheral vision.
A formal visual field examination may therefore be arranged, particularly when the tumour is close to the optic chiasm.
Testing other pituitary hormones
A pituitary tumour can affect the production of other hormones.
Your endocrinologist may therefore arrange additional blood tests to assess pituitary function, including hormones involved in the thyroid, adrenal and reproductive systems.
How is acromegaly treated?
The aim of treatment is to:
- Reduce excessive growth hormone production or block its effects
- Bring IGF-1 into the appropriate target range
- Control or remove the pituitary tumour where possible
- Protect vision and other important structures
- Improve symptoms and quality of life
- Identify and treat complications
- Preserve or replace other pituitary hormones where necessary
Treatment is individualised and may involve surgery, medication, radiotherapy, or a combination of treatments.
Current international recommendations emphasise an individualised, multidisciplinary approach to the management of acromegaly. (PubMed)
Surgery
For many people with a pituitary tumour causing acromegaly, surgery is an important first-line treatment, particularly when the tumour can be safely removed.
Pituitary surgery is usually performed through the nose using a technique called transsphenoidal surgery.
Modern surgery is commonly performed using an endoscopic approach, allowing the neurosurgeon to access the pituitary gland through the nasal passages without opening the skull.
The likelihood of achieving remission depends on factors including:
- The size of the tumour
- The tumour's location
- Whether it has grown into surrounding structures
- Pre-treatment hormone levels
- The experience of the pituitary surgical team
Surgery may reduce GH and IGF-1 levels substantially, but it does not always completely control acromegaly.
If excess hormone production remains after surgery, additional treatment may be recommended.
Medication
Several medicines can be used to treat acromegaly.
The choice of treatment depends on factors including the size and characteristics of the tumour, hormone levels, previous treatment, other medical conditions and individual circumstances.
Somatostatin receptor ligands
Somatostatin receptor ligands (SRLs) reduce the secretion of growth hormone from the pituitary tumour.
Commonly used treatments include:
- Octreotide
- Lanreotide
These medicines are generally given as long-acting injections.
Some people respond very well to these treatments, while others may require additional or alternative therapy.
Possible side effects can include gastrointestinal symptoms and changes affecting the gallbladder.
Pegvisomant
Pegvisomant works differently from medicines that reduce GH secretion.
It is a growth hormone receptor antagonist, meaning that it blocks the action of growth hormone on tissues and reduces the production of IGF-1.
Pegvisomant can be used when acromegaly is not adequately controlled with other treatments and may also be used in combination with other medicines in selected patients.
Regular blood tests and monitoring are required during treatment.
Dopamine agonists
Cabergoline is an oral medicine that can be used in some people with acromegaly, particularly when hormone elevations are relatively modest or in combination with other treatment.
It is generally less effective than somatostatin receptor ligands when used alone, but can be useful in selected patients.
Other medical treatments
Treatment options for acromegaly continue to develop.
Depending on individual circumstances and availability, specialist centres may also consider treatments such as pasireotide or newer oral and injectable therapies.
Pasireotide can be effective in controlling acromegaly but can increase blood glucose levels, so appropriate monitoring is important. (PubMed)
Because the availability and licensing of medicines can change, your endocrinologist will advise you about the treatments available and appropriate for you in Ireland.
Radiotherapy
Radiotherapy may be considered when:
- A pituitary tumour cannot be completely removed
- Acromegaly remains uncontrolled despite surgery and medication
- Further surgery is not appropriate
- Medication is not effective, tolerated or suitable
Modern radiotherapy can be precisely targeted at the tumour while limiting exposure to surrounding tissues.
Stereotactic radiotherapy, including stereotactic radiosurgery in appropriate cases, may allow a highly focused dose of radiation to be delivered to the tumour.
Radiotherapy does not usually control hormone production immediately. The full effect may take months or several years.
During this period, medication may continue to control GH and IGF-1 levels.
Radiotherapy can also affect normal pituitary tissue, so long-term monitoring of pituitary hormone function is important.
Monitoring and managing complications
Successful treatment of acromegaly involves more than controlling GH and IGF-1.
People with acromegaly may need ongoing assessment for complications and associated conditions, including:
- High blood pressure
- Diabetes or impaired glucose regulation
- Cardiovascular disease
- Sleep apnoea
- Joint and bone problems
- Carpal tunnel syndrome
- Changes in vision
- Other pituitary hormone deficiencies
- Colon and other health concerns identified by your clinical team
International recommendations emphasise regular assessment and management of these associated conditions. (OUP Academic)
What happens after successful treatment?
When acromegaly is brought under good biochemical control, many people experience an improvement in their symptoms and overall health.
Soft-tissue swelling may decrease, and hands and feet may become smaller. Excessive sweating, headaches and other symptoms may improve.
Sleep apnoea, blood glucose problems and cardiovascular risk factors may also improve when acromegaly is effectively controlled.
However, some physical changes caused by long-standing acromegaly may not completely reverse.
For example, enlargement or structural changes to bones and joints can persist even after GH and IGF-1 have returned to the appropriate range.
This is why early diagnosis and effective long-term management are so important.
Living with acromegaly
Acromegaly is a chronic condition and some people require lifelong monitoring and treatment.
Even when hormone levels are well controlled, regular follow-up with your endocrinology team is important.
Your healthcare team may monitor:
- IGF-1 and growth hormone levels
- Pituitary function
- The pituitary tumour using MRI where appropriate
- Blood pressure and cardiovascular health
- Blood glucose
- Sleep apnoea
- Joint and bone health
- Vision
- Other complications associated with acromegaly
Treatment can be highly effective, and with appropriate specialist care many people with acromegaly can live active and fulfilling lives.
When should you speak to your doctor?
If you have noticed gradual changes such as increasing shoe or ring size, changes in facial appearance, persistent headaches, excessive sweating, sleep apnoea, joint problems or other symptoms associated with acromegaly, speak to your GP.
These symptoms do not necessarily mean that you have acromegaly, but persistent or unexplained combinations of symptoms may warrant further assessment.
If your GP suspects a pituitary or hormonal disorder, you may be referred to an endocrinologist for specialist assessment.
Important information
The information provided by Pituitary Ireland is intended for general information and educational purposes. It is not a substitute for professional medical advice, diagnosis or treatment.
If you are concerned about symptoms or your treatment, speak with your GP, endocrinologist or other qualified healthcare professional.
Do not stop, change or delay prescribed medication without discussing this with your healthcare team.
Pituitary Ireland supports people living with pituitary conditions and their families and is committed to providing reliable, accessible information about pituitary health.