Graves' disease

Graves' disease is autoimmune thyroid disease. The body produces antibodies against the thyroid gland causing it to become overactive, resulting in increased thyroid hormone production and hyperthyroidism.

Alternative names for Graves’ disease

Autoimmune hyperthyroidism

What is Graves’ disease?

Graves’ disease is the name given to autoimmune thyroid disease. The thyroid gland is stimulated by auto-antibodies, which make it overactive, resulting in increased thyroid hormone production. Graves’ disease is named after the doctor who first described it, Robert Graves, and is the most common cause of hyperthyroidism. 

What causes Graves’ disease?

The body reacts to the thyroid gland and produces special proteins (called antibodies) that attack the thyroid gland. This is called an autoimmune reaction. These antibodies then stimulate the thyroid gland causing increased production and release of thyroid hormones. This reaction can be triggered by infection, stress or smoking.

What are the signs and symptoms of Graves’ disease?

These are the same for any kind of thyroid overactivity, irrespective of the cause. Common symptoms and signs include:

  • palpitations (heart beating fast, occasionally irregularly)
     
  • a sensation of feeling hot and excessive sweating
     
  • weight loss – although appetite is usually good (and sometimes better than normal)
     
  • increased frequency of bowel movements
     
  • shaking of hands
     
  • muscle weakness and loss of muscle bulk
     
  • swelling of nail beds
     
  • a feeling of thirst and frequent urination
     
  • difficulty in sleeping, restlessness, agitation and a change of behaviour
     
  • periods may become irregular (usually becoming lighter).

There may also be related swelling of the thyroid gland in the neck causing difficulty in swallowing and breathing.

Graves’ disease can affect the eyes. They may become swollen and red, sometimes becoming more prominent and in severe cases, there may be double vision and squinting. This is called Graves’ ophthalmopathy or thyroid eye disease. See the article on thyoid eye disease for further information.

There may be specific skin changes affecting the front of the legs, where the skin looks red and swollen. This is called Graves’ dermopathy or pretibial myxedema.

If left untreated, Graves’ disease can lead to heart failure.

How common is Graves’ disease?

Just over 1% of people suffer from an overactive thyroid gland from any cause. Women are five times more likely to suffer from it than men.

Graves’ disease affects about 5 in 1,000 people. Like any autoimmune condition, Graves’ disease is more common in women than men.

Is Graves’ disease inherited?

Graves’ disease is not inherited. However, it has been seen to affect members of the same family. An identical twin is more likely to have Graves’ disease if the other twin is affected. Although there is a tendency for autoimmunity to be inherited, a mother cannot ‘pass on’ an overactive thyroid to her child.

How is Graves’ disease diagnosed?

The diagnosis happens in two parts:

  1. Overactivity of the thyroid gland can be assessed by a blood test to check thyroid function and measure the levels of thyroid hormones in the blood. This would include various combinations of thyroid stimulating hormone (the messenger hormone from the brain), free thyroxine and free triiodothyronine. Usually levels of thyroid stimulating hormone and free thyroxine are checked as a first step.
     
  2. Graves’ disease can be confirmed by measuring thyroid antibodies (thyroid peroxidise or thyroid stimulating hormone receptor antibodies) or by a special scan of the thyroid called an isotope scan (this is different from an ultrasound scan). However, diagnosis is usually clear from the symptoms and on many occasions these additional tests may not be needed.

Usually these tests are all done as an outpatient.

How is Graves’ disease treated?

Symptoms of thyrotoxicosis (high levels of thyroid hormones) can be treated with beta-blockers (provided the patient can tolerate it). This is often the first type of treatment used. Although this can settle symptoms down, it does not affect the inflammation.

Anti-thyroid drugs, carbimazole or propylthouracil, are used to treat the actual inflammation of the thyroid gland. Carbimazole is the first type of drug chosen and propylthouracil is usually used during pregnancy and breastfeeding. The duration of treatment is variable depending on the individual patient, ranging between 6 months to 24 months.

Some centres use a treatment regime called ‘block and replacement’, which involves ‘blocking’ the action of the thyroid gland completely with carbimazole and then ‘replacing’ the required thyroxine level with thyroid tablets. Alternatively, a titration regime may be used, where enough of the drug is given to partly suppress the thyroid gland and keep the body’s natural thyroid hormone levels within a normal range.

Other kinds of treatment can be used once the acute thyrotoxicosis has settled. This could be in the form of surgery (to remove the gland) or radioiodine treatment (causes gradual destruction of the thyroid gland). There are pros and cons of both these methods and the specialist will discuss these with the patient.

Some patients do not need surgery or radioiodine treatment as the tablets can settle down the inflammation adequately and the thyroid gland can function normally after that.

Are there any side-effects to the treatment?

Carbimazole can cause joint pain and an itchy rash. Most importantly, carbimazole can acutely reduce the white cell count in the body and thus reduces the body’s power to fight infections. Should patients develop a fever, sore throat or become more unwell in any way they must contact their GP or be seen in the emergency department for a blood test to check the cell count. Although very rare, this complication can be fatal if the diagnosis is delayed.

Propylthouracil, if used for a long time, can cause inflammation of blood vessels called vasculitis. This can affect all the organs.

What are the longer-term implications of Graves’ disease?

There will be a chance of Graves’ disease returning after one episode but the likelihood will reduce with time. Smoking can worsen thyroid eye disease associated with this condition, so it is important to stop immediately.

Surgery, and in many cases radioiodine, will result in the thyroid becoming underactive, meaning that the patient will have to take thyroid hormone replacement (levothyroxine) for the rest of their life. The alternative to surgery or radioiodine is to take an anti-thyroid drug for a prolonged period of time (up to lifelong). The disadvantage of this approach is that patients can still have a flare of Graves’ disease.


Last reviewed: Jan 2015