Acromegaly

Introduction

Acromegaly is an uncommon hormonal condition that develops slowly over many years. Because the changes it causes are gradual — a ring that no longer fits, shoes that need to be a size larger, a slight change in facial features — the diagnosis is often made long after the condition has started. By the time most people are told they have acromegaly, they have lived with symptoms for several years and seen more than one doctor.

If you have just been diagnosed, or you are being investigated for acromegaly, this guide is written for you. It explains what the condition is, why it happens, how it is confirmed, and the treatments that doctors use to bring growth hormone levels back under control. It also covers what daily life and long-term follow-up usually look like, because acromegaly is a condition that almost always needs ongoing care, even after successful treatment.

Acromegaly is treatable. With the right combination of surgery, medication, and monitoring, most people achieve good biochemical control, see improvement in symptoms, and reduce their risk of long-term complications. The road can feel long at first, but it is well-mapped.

What Is Acromegaly?

Acromegaly is a chronic condition caused by too much growth hormone (GH) in the body over a long period. Growth hormone is made by the pituitary gland, a small gland about the size of a pea that sits at the base of the brain. In healthy adults, growth hormone helps maintain tissues, muscle, and bone. When too much is produced — almost always because of a non-cancerous tumour in the pituitary gland — it drives the liver and other tissues to produce high levels of a second hormone called insulin-like growth factor 1 (IGF-1). IGF-1 is the messenger that causes most of the physical and metabolic changes seen in acromegaly.

When excess growth hormone occurs in adulthood, after the growth plates in the bones have closed, the condition is called acromegaly. The body cannot grow taller, so the soft tissues, internal organs, and the ends of the bones (hands, feet, jaw, brow) gradually enlarge instead. When the same hormonal problem occurs in childhood, before the growth plates close, it causes gigantism — abnormally tall stature in addition to the other changes. This is covered in a separate section below.

Acromegaly is rare. Estimates suggest a few cases per million people each year, with several tens of cases per million living with the condition at any time. It affects men and women equally and is most often diagnosed between the ages of 30 and 50, although the underlying tumour has usually been present for years before diagnosis.

Causes and Risk Factors

The Pituitary Tumour

In more than 95% of cases, acromegaly is caused by a benign tumour of the pituitary gland called a somatotroph adenoma. “Benign” means it is not cancer and does not spread. However, because the tumour’s cells produce growth hormone continuously and without the normal feedback controls, the body is exposed to far more GH than it needs.

Pituitary tumours are described by size:

• Microadenoma — smaller than 10 mm
• Macroadenoma — 10 mm or larger

Most acromegaly-causing tumours are macroadenomas at the time of diagnosis, because the condition is usually identified late. Larger tumours can press on nearby structures — particularly the optic nerves — which is why some people first notice changes in their vision.

Rare Causes

In a small number of cases, acromegaly is caused not by a pituitary tumour but by a tumour elsewhere in the body that produces growth hormone-releasing hormone (GHRH), which then stimulates the pituitary to produce GH. These ectopic sources can include tumours in the pancreas or lungs and are uncommon. Even more rarely, a tumour outside the pituitary produces growth hormone directly.

Genetic Conditions

Most cases of acromegaly happen sporadically, with no family history. A minority are linked to inherited genetic syndromes, including:

• Multiple endocrine neoplasia type 1 (MEN1)
• Familial isolated pituitary adenoma (FIPA), including mutations in the AIP gene
• Carney complex
• McCune-Albright syndrome
• X-linked acrogigantism (X-LAG), which typically causes gigantism in young children

If acromegaly is diagnosed at a young age, in more than one family member, or alongside other endocrine tumours, doctors may suggest genetic evaluation.

Things That Do Not Cause Acromegaly

Acromegaly is not caused by diet, lifestyle, stress, or anything you did or did not do. It cannot be prevented. Understanding this can help patients let go of self-blame that sometimes accompanies a delayed diagnosis.

Signs and Symptoms

For readers who already have a diagnosis, this section may help you make sense of changes you have noticed over the years, and recognise which features are likely to improve with treatment. The symptoms of acromegaly fall into two broad groups: changes from the excess growth hormone itself, and changes caused by the tumour pressing on nearby structures.

Changes from Excess Growth Hormone

These develop gradually over years and may include:

• Enlargement of the hands and feet — rings becoming tight, shoe size increasing in adulthood
• Coarsening of facial features — a more prominent jaw and brow, wider nose, larger lips, gaps appearing between teeth
• Thickened, oily skin and skin tags
• Excessive sweating and body odour
• Deepening of the voice
• Joint pain and stiffness, often affecting the knees, hips, shoulders, and back
• Carpal tunnel syndrome — numbness or tingling in the hands
• Sleep apnoea — loud snoring, pauses in breathing during sleep, daytime tiredness
• Fatigue and reduced exercise tolerance
• Changes in menstrual cycles in women; reduced libido or erectile dysfunction in men
• Higher blood sugar, sometimes diagnosed as type 2 diabetes
• High blood pressure

Changes from the Pituitary Tumour Itself

When the tumour is large, it may press on:

• The optic chiasm — causing loss of peripheral (side) vision, particularly the outer halves of the visual field
• The rest of the pituitary gland — reducing the production of other hormones (thyroid, cortisol, sex hormones), causing fatigue, low mood, infertility, or loss of body hair
• Surrounding tissues — causing headaches

Diagnosis

Diagnosis usually involves three steps: confirming that growth hormone activity is too high, confirming that it is not being suppressed normally, and then locating the tumour.

IGF-1 Blood Test

The first test is usually a blood measurement of IGF-1. Unlike growth hormone itself, which fluctuates throughout the day, IGF-1 levels are stable and reflect the average growth hormone exposure over the previous day or two. An IGF-1 level well above the normal range for your age and sex strongly suggests acromegaly. The Endocrine Society describes IGF-1 as the preferred screening test.

Oral Glucose Tolerance Test (OGTT) with GH Measurement

To confirm the diagnosis, doctors use a growth hormone suppression test. You drink a sugary solution (75 grams of glucose), and your growth hormone levels are measured at intervals over the following two hours. In a healthy person, the rise in blood sugar suppresses growth hormone. In acromegaly, growth hormone fails to suppress. This test is considered the gold standard for confirming the diagnosis.

Pituitary MRI

Once the biochemical diagnosis is made, an MRI scan of the pituitary gland is performed to identify the tumour, measure its size, and see whether it is pressing on nearby structures such as the optic nerves or extending into the cavernous sinuses on either side. The MRI findings strongly influence the treatment plan.

Additional Testing

Because acromegaly affects many body systems, additional tests are commonly arranged at diagnosis to look for complications and to check the rest of pituitary function:

• Tests of other pituitary hormones (thyroid, cortisol, prolactin, sex hormones)
• Formal visual field testing if the tumour is near the optic chiasm
• Blood glucose, HbA1c, and lipid profile
• Blood pressure assessment
• Echocardiogram, because the heart muscle can thicken in acromegaly
• Sleep study if sleep apnoea is suspected
• Colonoscopy, as people with acromegaly have a higher risk of colon polyps

This wider work-up helps the team plan treatment and address complications alongside the underlying condition.

Treatment

The goals of acromegaly treatment are to:

• Bring growth hormone and IGF-1 levels back to the normal range
• Remove or shrink the pituitary tumour
• Preserve normal pituitary function
• Relieve symptoms
• Treat or prevent complications such as diabetes, hypertension, sleep apnoea, and heart disease

Treatment is usually a combination of surgery, medication, and — in some cases — radiotherapy. Care is best provided by a team that includes an endocrinologist, a neurosurgeon with experience in pituitary surgery, a neuroradiologist, and often other specialists depending on the complications present. The Endocrine Society and Pituitary Society both emphasise the value of multidisciplinary, high-volume pituitary care.

Surgery: Transsphenoidal Pituitary Surgery

For most people with acromegaly, surgery is recommended by current guidelines as the first-line treatment. The standard operation is transsphenoidal surgery, in which the surgeon reaches the pituitary gland through the nose and the sphenoid sinus — an air-filled space behind the nasal cavity. Modern transsphenoidal surgery is usually performed endoscopically, using a thin camera that gives the surgeon a clear view without external incisions.

Surgery is most likely to bring growth hormone fully into the normal range when:

• The tumour is small (a microadenoma)
• The tumour has not invaded surrounding structures
• The surgeon is highly experienced in pituitary surgery

Remission rates are substantially better for microadenomas than for large invasive macroadenomas. Even when surgery does not achieve complete biochemical control, removing or debulking the tumour usually makes subsequent medical treatment more effective. After surgery, growth hormone levels are checked early (often within a week) and IGF-1 levels are reassessed at 12 weeks, when they have had time to settle into their new pattern.

Medications

Somatostatin receptor ligands (SRLs) — These drugs, including octreotide and lanreotide, mimic the body’s natural hormone somatostatin, which suppresses growth hormone release. They are given as long-acting injections, usually once a month. SRLs lower GH and IGF-1 in most patients and can also shrink the tumour. A newer SRL, pasireotide, is sometimes used when first-generation SRLs do not provide adequate control, though it can raise blood sugar. SRLs are widely used by endocrinologists as the main medical option.

Growth hormone receptor antagonist — Pegvisomant is a daily injection that blocks the action of growth hormone in the body’s tissues. It does not shrink the tumour, but it is highly effective at normalising IGF-1 in patients who do not respond fully to SRLs. Liver function is monitored during treatment.

Dopamine agonists — Cabergoline, taken as oral tablets, can lower GH and IGF-1 in some patients, particularly those with milder elevations or with tumours that also produce prolactin. It is generally less potent than the injectable options but can be useful as add-on therapy or as the only treatment in mild cases.

Combinations of these medications are sometimes used when a single drug does not provide complete control. The choice depends on tumour characteristics, IGF-1 levels, side effects, other medical conditions (especially diabetes), and individual response.

Radiotherapy

Radiation therapy is generally reserved for tumours that cannot be fully removed by surgery and that are not adequately controlled by medication, or when medication cannot be used. Modern approaches include:

• Stereotactic radiosurgery (such as Gamma Knife or CyberKnife) — a focused dose delivered in one or a few sessions, suitable for smaller, well-defined tumours that are not too close to the optic nerves
• Fractionated radiotherapy — smaller doses given over several weeks, used for larger or more complex tumours

Radiotherapy works slowly. Growth hormone levels typically fall over several years, and medication is usually continued during this period. The main long-term concern is gradual loss of normal pituitary hormone production (hypopituitarism), which can develop years after treatment and requires ongoing monitoring and hormone replacement when needed.

Treatment Sequencing

Most often, treatment follows the pattern of surgery first, then medical therapy if biochemical control is not achieved, with radiotherapy held in reserve. However, in some situations — very large tumours, certain comorbidities, or tumours unlikely to be cured by surgery — doctors may start with medication, plan a staged approach, or combine modalities from the outset. The decision is individual and is best made together with a specialist team.

Biochemical Targets and Monitoring

Successful treatment is judged by both clinical improvement and biochemical control. Current guidance from the Endocrine Society and the Pituitary Society defines control as:

• IGF-1 within the normal range for age and sex
• Growth hormone levels that are appropriately suppressed

• IGF-1 and growth hormone testing at intervals (more frequently in the first year, then usually yearly once stable)
• MRI scans periodically to check for tumour residual or recurrence
• Tests of other pituitary hormones
• Visual field assessment if the tumour was close to the optic chiasm
• Monitoring and treatment of complications

For most patients, follow-up is lifelong, though it usually becomes less frequent once a stable pattern is established.

Complications and How They Are Managed

Acromegaly affects many systems of the body, and several of the complications need treatment in their own right alongside the underlying hormonal problem. Many of these improve with effective treatment of the acromegaly, but some require dedicated long-term management.

Cardiovascular Disease

Heart disease is the most important cause of excess illness and shortened life expectancy in untreated acromegaly. Excess growth hormone causes thickening of the heart muscle (acromegalic cardiomyopathy), high blood pressure, and changes in heart valves. Effective treatment, blood pressure control, and statins where indicated reduce these risks. Regular cardiology follow-up is often arranged.

Diabetes and Insulin Resistance

Growth hormone opposes the action of insulin, so many people with acromegaly develop high blood sugar, prediabetes, or type 2 diabetes. Blood sugar often improves after successful treatment of acromegaly, but ongoing management of diabetes — lifestyle changes, oral medications, or insulin — may still be required.

Sleep Apnoea

Enlargement of the soft tissues in the upper airway and the tongue causes obstructive sleep apnoea in a large proportion of patients. Sleep apnoea typically improves with treatment but may not fully resolve. Continuous positive airway pressure (CPAP) is often used.

Joint Disease

Acromegalic arthropathy — joint pain and stiffness from changes in cartilage and bone — is one of the symptoms most likely to persist even after successful treatment, because some of the joint changes are permanent. Physiotherapy, pain management, and, in some cases, joint replacement surgery may be considered later in life.

Colon Polyps

Acromegaly is associated with a higher risk of colon polyps and, to a smaller degree, colorectal cancer. Many guidelines recommend a baseline colonoscopy at diagnosis, with repeat colonoscopies at intervals based on findings and biochemical control.

Thyroid Nodules

Thyroid nodules are more common in acromegaly. Thyroid ultrasound and palpation are part of routine assessment.

Hypopituitarism

Some patients develop reduced production of other pituitary hormones — either because of the tumour itself, surgery, or radiotherapy. This can mean lifelong hormone replacement, including thyroid hormone, hydrocortisone, sex hormones, or, occasionally, growth hormone in a separate context. Replacement is closely supervised by an endocrinologist.

Living with Acromegaly

Acromegaly is a lifelong condition for most people, even when biochemical control is excellent. The day-to-day reality of living with it usually settles into a pattern of regular check-ups, taking or receiving medications, and managing any complications.

Physical and Emotional Adjustment

Because acromegaly causes visible changes — sometimes substantial ones — many people find the diagnosis emotionally difficult. Features that developed gradually may not fully reverse with treatment. Soft-tissue swelling often reduces noticeably, hands and feet may decrease in size somewhat, and skin and sweating tend to improve, but bony changes — the shape of the jaw, brow, or hands — remain. Counselling, support groups, and connection with others who have acromegaly can help.

Diet, Exercise, and Daily Habits

Lifestyle does not cure acromegaly, but it supports overall health, especially in the presence of diabetes, high blood pressure, and joint disease. A balanced diet, regular activity within joint comfort, weight management, good sleep hygiene, and avoidance of smoking all play a role. Many patients work with a dietitian and a physiotherapist as part of their wider care.

Fertility and Pregnancy

Acromegaly can affect menstrual cycles and fertility in women, and testosterone levels and erectile function in men. Many of these issues improve with treatment. Pregnancy is possible in women with acromegaly but is planned carefully, because some acromegaly medications are not used during pregnancy and the tumour may behave differently during this time. Pre-pregnancy planning with an endocrinologist is important.

Work and Activities

Most people with treated acromegaly continue to work and pursue their usual activities. Energy levels and joint comfort often improve substantially with treatment. Adjustments may be needed if sleep apnoea, joint problems, or vision changes are present.

Acromegaly and Gigantism in Children

When excess growth hormone occurs before the growth plates in the bones close — that is, before puberty is complete — the resulting condition is called pituitary gigantism. It is extremely rare. The same kinds of pituitary tumours that cause acromegaly in adults can cause gigantism in children, but because the long bones can still grow, the most striking feature is abnormally rapid growth and unusually tall stature.

Other features overlap with adult acromegaly:

• Large hands and feet
• Coarse facial features
• Headaches and vision changes if the tumour is large
• Delayed puberty
• Excessive sweating and thickened skin

Pituitary gigantism is more likely than adult acromegaly to have an underlying genetic cause. Conditions such as X-linked acrogigantism (X-LAG), AIP-related familial pituitary adenomas, McCune-Albright syndrome, and Carney complex are over-represented in this group. Genetic evaluation is usually part of the work-up, and other family members may be screened.

Treatment principles are similar to those in adults — transsphenoidal surgery, medications such as somatostatin analogues or pegvisomant, and radiotherapy in selected cases — but care is delivered by a paediatric endocrine team in close coordination with paediatric neurosurgery and, when needed, genetics. Growth, puberty, and overall development are tracked carefully alongside hormonal control. With effective treatment, growth slows and most other features can be managed, though final adult height is often above average.

When to Seek Medical Attention

If you are being treated for acromegaly, certain symptoms should prompt earlier contact with your team rather than waiting for your next scheduled appointment:

• Sudden severe headache, especially with vomiting or visual disturbance — this could indicate pituitary apoplexy (bleeding into the tumour), a rare but urgent event
• New or worsening loss of vision, particularly side vision
• Severe fatigue, dizziness, nausea, or low blood pressure — possible signs of adrenal insufficiency, especially in patients on hydrocortisone replacement
• Unexplained fever, vomiting, or feeling very unwell when on hormone replacement (a “sick day” plan for steroid cover is usually agreed with your endocrinologist)
• Clear, watery fluid leaking from the nose after pituitary surgery
• Signs of new diabetes or worsening glucose control

Your endocrine team will give you specific guidance on what to watch for based on your individual situation.

Frequently Asked Questions

Is acromegaly cancer?

No. The pituitary tumour that causes acromegaly is almost always benign, meaning it does not spread to other parts of the body. The problem is the hormone it produces, not the tumour’s ability to spread.

Can acromegaly be cured?

For some people — particularly those with small, non-invasive tumours operated on by experienced pituitary surgeons — surgery alone can bring growth hormone and IGF-1 levels fully into the normal range, and this is often described as remission. Others achieve excellent control with a combination of treatments. Because there is always a possibility of late recurrence, lifelong monitoring is recommended even after apparent cure.

Will my appearance return to normal after treatment?

Soft-tissue changes — swelling of the hands, feet, lips, and facial features, oily skin, and excess sweating — usually improve, sometimes substantially. Changes to the underlying bones, including the jaw and brow, generally remain. Many people notice the difference clearly within months of effective treatment.

Why has my diagnosis taken so long?

Delayed diagnosis is common in acromegaly. The changes are gradual, often subtle, and easily attributed to ageing or other conditions. Studies suggest an average delay of several years between the first symptoms and the diagnosis. This is not unusual and not anyone’s fault.

Is acromegaly inherited?

Most cases are not inherited and occur sporadically. A small minority are part of genetic syndromes. If acromegaly is diagnosed in childhood or early adulthood, or in more than one family member, genetic testing may be offered.

Will I need treatment for life?

Some people who achieve full remission after surgery do not require ongoing medication, but they still need lifelong monitoring. Many others continue on medication long-term. Either way, regular follow-up is part of life with acromegaly.

Can I have children?

Yes, in most cases, although acromegaly can affect fertility. Many people with treated acromegaly have children. Pregnancy in women with acromegaly is best planned in advance with the endocrine team, because medications and tumour behaviour need to be reviewed.

Does diet or exercise affect acromegaly?

Diet and exercise do not affect growth hormone production by the tumour. They do, however, play an important role in managing the complications — particularly diabetes, blood pressure, weight, and joint health — that often accompany acromegaly.

Conclusion

Acromegaly is a rare, chronic condition that develops slowly and is often diagnosed years after it begins. The diagnosis can be unsettling, particularly because the changes it causes are visible and have built up over time. The reassuring reality is that acromegaly is treatable. With surgery, medications, and — when needed — radiotherapy, growth hormone and IGF-1 levels can usually be brought back into the normal range, complications can be managed, and excess long-term risk can be substantially reduced.

Care for acromegaly is best delivered by a team familiar with pituitary disease and continues across the years rather than ending after a single intervention. With consistent follow-up and attention to the complications that accompany the condition, most people with acromegaly live full, active lives.