Acromegaly (Excess Growth Hormone)

Acromegaly is a condition in which the body produces too much growth hormone in adulthood. The excess hormone drives slow changes in the bones and soft tissues, especially of the hands, feet, and face. Because the changes develop gradually, the condition is often recognised late, and blood tests and imaging are central to diagnosis.

What acromegaly is

Growth hormone is made by the pituitary gland at the base of the brain. It acts partly directly on tissues and partly by prompting the liver and other tissues to release insulin-like growth factor 1 (IGF-1), which carries out many of its effects. IGF-1 is steadier in the blood than growth hormone itself, which makes it a useful marker of overall activity. In childhood, before the growth plates at the ends of the long bones close, excess growth hormone causes excessive height, a condition called gigantism. In adulthood, the bones can no longer lengthen, so instead they thicken and soft tissues enlarge — this is acromegaly.

The excess hormone usually comes from a benign growth of the pituitary gland. Because the changes occur over years, people often do not notice them, and they are sometimes spotted only when an old photograph or an old pair of gloves makes the difference obvious. Left unaddressed, the sustained excess can affect the heart, joints, breathing, and the way the body handles blood sugar, which is why timely evaluation and ongoing follow-up matter.

Common signs and symptoms

Signs develop slowly and reflect both the growth of bone and soft tissue and the effects of the hormone on other systems. They may include:

• Enlargement of the hands and feet, such as rings or shoes no longer fitting
• Coarsening of facial features, including a more prominent jaw or brow and fuller lips
• Increased spacing between the teeth and changes in the bite
• Thickened, oily skin and increased sweating
• Joint aches, stiffness, and reduced mobility
• Numbness or tingling in the hands, sometimes from carpal tunnel syndrome
• Headaches and, when a pituitary growth presses on nearby structures, vision changes
• Tiredness, snoring, or interrupted breathing during sleep
• Changes in menstrual cycles, sexual function, or milk-like breast discharge
• A deeper voice as the soft tissues of the voice box thicken

Many people first seek help for a single problem, such as joint pain or sleep difficulties, and the broader pattern only becomes clear when a clinician puts the features together.

What causes it

The great majority of acromegaly is caused by a benign tumour of the pituitary gland, called a pituitary adenoma, that secretes growth hormone. The size of the tumour partly shapes the picture: a larger one can press on neighbouring tissue and affect vision or the gland's other hormones. Much more rarely, the excess comes from elsewhere — for example a tumour outside the pituitary that releases a growth-hormone-releasing signal, or, very rarely, a tumour that makes growth hormone directly. The reasons these tumours develop are an area of ongoing research, and most cases are not inherited, although a small number relate to recognised genetic conditions, which is why family history is sometimes explored.

How it is diagnosed

Because growth hormone is released in pulses through the day and night, a single random measurement is not reliable, so clinicians use tests that reflect overall activity. Diagnosis typically involves:

• IGF-1 — a blood test that reflects average growth hormone activity and is the usual screening test; results are interpreted against age and sex.
• An oral glucose suppression test — measures whether growth hormone falls normally after a sugary drink; in healthy people the level drops sharply, and a failure to suppress supports the diagnosis.
• Pituitary imaging — usually an MRI, to look for and locate a pituitary tumour and judge its size.
• Other pituitary hormone tests — to assess whether the gland's other functions, such as thyroid, adrenal, and reproductive hormones, are affected.

An eye examination is sometimes arranged when a tumour is large enough to affect vision, and tests of blood sugar, blood pressure, and heart function may be done because of the condition's wider effects. The table below shows, in general terms, how these tests fit together; it is illustrative only and not a basis for self-diagnosis.

For background on the markers themselves, see our blood tests and hormones sections, and our conditions overview for related pituitary topics.

How it is generally managed

Management aims to lower growth hormone activity, relieve symptoms, and address any tumour, and it is decided with a clinician; this page does not describe medicines or doses. General approaches can include surgery to remove a pituitary tumour, medicines that reduce growth hormone production or block its effects, and, in some situations, radiation therapy. The choice depends on the tumour, the level of hormone activity, and individual circumstances, and more than one approach is sometimes combined. Care also commonly includes ongoing monitoring of the heart, joints, blood sugar, sleep, and other hormones over time. General treatment principles are outlined in our treatments section, and our symptoms overview can help you describe changes you have noticed.

Complications and when to seek care

Sustained excess growth hormone can place strain on several systems. Over time it can affect the heart and blood pressure, contribute to sleep apnoea, raise blood sugar, and lead to joint problems that may persist even after the hormone is controlled. A large pituitary tumour can press on the optic nerves and affect vision, or reduce the gland's other hormones. New or worsening headaches, changes in vision, or sudden severe symptoms are reasons to seek prompt medical attention rather than waiting.

Living with acromegaly

Because some changes develop over years, follow-up after diagnosis is typically long-term and focuses on keeping hormone activity controlled and watching for the condition's wider effects. Regular review of IGF-1, periodic imaging, and checks of blood pressure, blood sugar, and sleep are common parts of ongoing care. Many of the symptoms, such as soft-tissue swelling and headaches, can ease once the hormone is brought under control, though some skeletal changes are lasting. Keeping a record of symptoms and bringing older photographs to appointments can help a clinician track progress over time.