Alternative names for goitre

Goiter: colloid goitre/goiter; nodular goitre/goiter; diffuse goitre/goiter; multi-nodular goitre/goiter; 

What is goitre?

Swollen neck of a patient with goitre.

The thyroid gland is a butterfly-shaped gland located in the neck. A normal-size thyroid cannot usually be felt. Any increase in size of the thyroid gland is called a goitre.

Goitre can be due to enlargement of the whole thyroid gland, known as ‘smooth goitre’ or ‘diffuse goitre’, or parts of the gland, called a ‘nodular’ or ‘cystic’ goitre. Many people with goitre have normal thyroid hormone levels but some can have an underactive thyroid (hypothyroidism) or an overactive thyroid (hyperthyroidism).

What causes goitre?

There are a number of different causes for goitre including:

• Iodine deficiency – iodine is an essential trace element that helps the thyroid gland to function properly and to make thyroid hormones. There are two main hormones called thyroxine and triiodothyronine. Approximately 29% of the world's population live in an iodine deficient area. In the UK, most people have sufficient iodine in their diet. Non-organic milk and dairy products are a good source of iodine, as well as seaweed, fish and eggs. In many countries table salt is supplemented with iodine, but in the UK it is not.
• Thyroiditis – this means inflammation of the thyroid gland. A number of causes can lead to swelling of the thyroid. The most common cause worldwide is Hashimoto's thyroiditis, which is due to immune cells attacking the thyroid gland (known as an autoimmune process) and is associated with the production of specific anti-thyroid antibodies. Thyroiditis can also occur for other reasons e.g. due to a viral infection, or during or shortly after a pregnancy. Hashimoto thyroiditis is often associated with reduced thyroid function called hypothyroid. Normal thyroid function can be maintained in the remaining cases; sometimes it can be anticipated by a transient increase of thyroid hormones levels due to their sudden release from the damaged gland.
• Graves' disease – this is an autoimmune disease where the immune system produces antibodies that persistently stimulate the thyroid, causing it to be over-active and produce too much thyroid hormone (hyperthyroidism). 
• Benign growths – these can take a number of different forms but follicular adenomas are the most common. They can be single (‘nodular goitre’) or, more frequently, multiple (‘multinodular goitre’). Thyroid nodules are usually associated with a normal thyroid function. 
• Toxic nodular goitre (Plummer’s disease) – this is where a nodule is over-functioning and producing too much thyroid hormone called hyperthyroidism.
• Goitrogens – these are factors that may cause the formation of goitre by disrupting the production of thyroid hormones. They include certain drugs or medicines (e.g. lithium, which is used in the treatment of mental health problems) and certain foods.
• Physiological causes – these include increased demands for hormone production during pregnancy and puberty.
• Inherited causes – there are a number of genetic conditions that can increase the likelihood of goitre formation.

What are the signs and symptoms of goitre?

It is common to have small nodules within the thyroid gland, which cannot be felt, but may be picked up incidentally when scans or examinations are conducted for other reasons. In these cases, there have usually been no symptoms to indicate the presence of goitre. Larger goitres simply present as a lump in the neck. Occasionally, a large goitre will press on nearby structures, for instance making it difficult to swallow or to breathe or affect the nerves that control the voice causing it to be hoarse. These are concerning features that should prompt urgent medical attention.

How common is goitre?

Worldwide, goitre is estimated by the World Health Organization to affect around 12% of people, although the rate of goitre in Europe as a whole is slightly lower. Goitre that is very common in a particular geographic area (called endemic) occurs in locations where there is iodine deficiency and is defined when more than 1 in 10 people have goitre.

Is goitre inherited?

Some forms of goitre can be inherited. There is some evidence that the presence of goitre in one family member increases the chances of other family members having goitre.

How is goitre diagnosed?

Goitre is diagnosed when the thyroid gland is enlarged enough to be felt by external touch or is clearly visible without a scan. Usually a GP will undertake thyroid function tests to measure the levels of thyroid hormones and thyroid antibodies in the bloodstream. They may also arrange an ultrasound scan or make a referral to an endocrinologist for outpatient assessment. Where more complex tests are required, they may include:

• ‘Fine needle aspiration’ (FNA) of the thyroid gland. A thin needle is inserted under the guidance of ultrasound to remove a very small amount of thyroid tissue, which is studied under a microscope to determine the cell type(s) that are present. This procedure may need to be repeated more than once to get an adequate result.
• A thyroid 'uptake' scan. This will pick up differences in the activity of different areas of the thyroid.  

How is goitre treated?

Treatment depends on the underlying cause of the goitre. ‘Simple’ goitre, where there is no thyroid hormone imbalance and no problems arising from the size of the thyroid, is unlikely to cause problems. In case the goitre is large and symptomatic (difficult to swallow or to breathe), it may be appropriate to consider surgery (a thyroidectomy), though this will result in the patient requiring lifelong thyroxine (thyroid hormone) replacement.

Treatment of overactive and underactive thyroid is explained in articles on hyperthyroidism and hypothyroidism, respectively.

Are there any side-effects to the treatment?

Surgery carries the normal risks of any operation (the risks from anaesthetic, post-operative infection, haemorrhage, bleeding and scar formation), and will result in an underactive thyroid. It can rarely cause specific complications with damage to the recurrent laryngeal nerve (controlling the voice box) resulting in a hoarse voice, or damage to the glands around the thyroid (parathyroidv glands), which control calcium. This may result in a low calcium level (hypocalcaemia) in the blood, which would require medication.

What are the longer-term implications of goitre?

For most people, there are no long-term implications of goitre, and no treatment is required unless there are specific reasons such as those described above.