Graves' disease is a form of overactivity of the thyroid gland. It's thought to be an autoimmune disease, where the immune system produces an antibody that interacts with the cells of the thyroid and stimulates them to secrete excessive amounts of thyroid hormones.

Insulin-dependent diabetes may also be an autoimmune condition and it's known there are links between autoimmune conditions. Graves' disease is linked to insulin-dependent diabetes and pernicious anaemia (another autoimmune condition), so when a person has one of these conditions they or members of their family may be at increased risk of developing another.

There's also a genetic influence contributing to Graves' disease and it can run in families.

Also known as thyrotoxicosis

Graves' disease is one of the most common problems of the thyroid gland, especially among women aged 30 to 50. Graves' disease is also often known as thyrotoxicosis, although strictly speaking this term means any toxic condition resulting from thyroid overactivity.

Symptoms include: weight loss, increased appetite, diarrhoea, tremor and shaking, irritability and emotional upsets, profuse sweating, dislike of hot weather, itching, reddening and thickening of the skin, typically over the shins, and infrequent periods.

Eye problems are typical

A very recognisable sign of Graves' disease (although not everyone with the condition has it very badly) are problems with the eyes, especially bulging eyes and retracted (or pulled back) upper eyelids. This exposes the delicate surface of the eye (the conjunctiva), which can become swollen and inflamed. Sometimes there's also double vision.

There may also be a goitre (or swelling of the thyroid gland in the neck) and swelling of the tissues over the front of the shins.

Steroids are used in severe cases

Treatment of Graves' disease aims to:

• Keep thyroid hormone levels in the normal range
• Prevent eye problems, which can result from exposure of the delicate eye tissues (this can be very difficult)

Treatment for the raised hormone levels may be:

• Drugs for immediate and then long-term control
• Surgery to remove part of the thyroid gland
• Radioactive iodine treatment or RAI

In recent years, efforts have been made to find a dose of RAI that will give a good cure rate for thyrotoxicosis without leading to underactivity (known as hypothyroidism). However, this has proved difficult and hypothyroidism remains a side-effect of the treatment, affecting as many as 20 per cent of those treated within the first couple of years after treatment, and three to five per cent more each year after that.

Those affected may need lifelong supplements of thyroid hormones.

Treatment for the eye problems includes:

• Drug treatments and eye drops to reduce swelling and close lids
• Steroids, especially if the eye muscles are paralysed or the swelling is very bad
• Surgery to reduce swelling or closed lids

This article was last medically reviewed by Dr Trisha Macnair in February 2008