This article was last reviewed on
This article waslast modified on 7 December 2023.
What is it?

Acromegaly is the name given to a condition caused by the body producing too much growth hormone (GH). The excess GH usually (about 95% of cases) comes from a non-cancerous tumour in the pituitary gland. It is a fairly rare disease with about 50 cases per million in the population. The increased amount of GH also leads to increased formation of another hormone, insulin-like growth factor (IGF-1).

These two hormones have a number of effects on the body most being due to an increase in size of tissue or organs.

The other 5% of cases of excess GH and acromegaly are caused by growth hormone-releasing hormone (GHRH) or GH being produced in tumours elsewhere in the body.

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About Acromegaly
  • Signs and symptoms

    In most cases the symptoms of acromegaly develop very slowly and signs may not be noticed for some time (several months).

    The external signs include:

    • Enlarged hands, making difficult or impossible to remove rings on fingers
    • Enlarged feet which can mean an increase in shoe size
    • Thickening of the lips
    • Enlarged, thickened nose
    • Increased size of the tongue
    • Increase in size of the bony ridges over the eyes
    • Changes in the jaw, making it difficult to bite normally
    • Deepening of the voice
    • Appearance of small extra skin growths, known as “skin tags”

    Other changes include:

    • Increases in size of the heart, thyroid, liver and spleen
    • Carpal tunnel syndrome. This is caused by an increase in the tissues of the wrist that press on the nerves and cause tingling and pins and needles in the fingers
    • Bone and joint pain
    • Increase risk of developing Type 2 diabetes 
    • Headaches and vision problems may occur due to the position of the associated pituitary tumour


  • Tests

    IGF-1 measured in the blood is the test of choice and will be raised in a patient with acromegaly. An elevated IGF-1 concentration in a patient showing signs of acromegaly confirms the diagnosis of acromegaly. Conversely, normal IGF-1 concentration suggests that acromegaly is unlikely.

    If diagnosis is unclear, then you may be asked to undertake an extended oral glucose tolerance test (OGTT), to assess GH concentration. During the test, a small plastic tube (cannula) will be placed in a vein to make taking blood samples easy. An initial blood sample will be taken to measure baseline GH and glucose. Following this, you will be asked to drink a glucose drink, and subsequently blood samples will be taken from the cannula every 30 minutes for 2 hours to measure GH and glucose. GH concentration should reduce significantly following the glucose drink, and a lack of reduction therefore indicates that too much GH is being produced.

    Apart from as part of an OGTT, measurement of GH is not helpful for diagnosing acromegaly, as GH is released in bursts at different times of the day and is affected by multiple other factors.

    An MRI scan of the pituitary will be carried out in patients with symptoms of acromegaly and a raised IGF-1. This is to identify thepresence of a tumour in the pituitary and to assess its size.

  • Treatment

    Surgical removal of the tumour is usual. This can often be achieved by an operation through the sinus passages behind the nose. The smaller the tumour the easier it is for the surgeon to remove the whole tumour. It is more difficult to completely remove large tumours totally and some tissue may be left.

    Total removal of the tumour will result in GH and IGF-1 levels in the blood falling quickly and symptoms will start to diminish. IGF-1 will be measured after surgery to assess whether all the tumour was removed.

    Sometimes the cells of the pituitary producing other hormones, such as Adrenocorticotrophic hormones (ACTH), thyroid stimulating hormone (TSH), luteinizing hormone (LH) and follicle stimulating hormone (FSH), are affected or removed and secretion of these hormones is lost. The patient will then be required to take hormone supplements such as thyroxine and cortisol depending on which hormones are lost.

    In difficult cases or where tumour removal is incomplete further treatment may be used. These include radiation and injections of drugs like octreotide (GH production blocker) or pegvisomant (GH action blocker). These drugs are slow acting and symptoms diminish gradually over the next couple of years.

    People with acromegaly should be regularly checked throughout their lives to ensure their treatment is working well and to reduce the chances of complications from the disease and side effects from treatment.