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Goitre

A goitre (sometimes spelt 'goiter') is an abnormal swelling of the thyroid gland that causes a lump to form in the throat.

The thyroid gland

The thyroid gland is a small butterfly-shaped gland in the neck that is located just in front of the windpipe (trachea). It produces thyroid hormones, which help to regulate the body's metabolism (the process that turns food into energy).

The thyroid gland is not usually noticeable. However, if it swells it produces a lump in the throat that is known as a goitre.

The size of a goitre can vary from person to person. In most cases, the swelling is small and does not cause any symptoms. However, in more severe cases, the swelling can increase so dramatically that breathing and swallowing are affected.

How common are goitres?

Goitres are a common condition, affecting an estimated 4-7% of people. However, in most cases, the swelling is so small that it cannot be seen. Goitres are more common in women than men.

Goitres can have a number of possible causes including:

• an overactive thyroid gland (hyperthyroidism)
• an underactive thyroid gland (hypothyroidism)
• pregnancy
• a lack of iodine (a trace mineral found in milk and fish) in the diet

Outlook

The treatment for goitres depends on the underlying cause. In many cases, if the goitre is small and it is not causing any problems, a wait-and-see approach is usually recommended.

Other possible treatments include thyroid hormone replacement, dietary supplements and, in the most severe cases, surgery. Although most goitres are usually benign (non-cancerous) it is estimated that in 1 in 20 cases they may be a sign of thyroid cancer.

Symptoms

The main symptom of a goitre is swelling of the thyroid gland (a gland in the neck that produces hormones) which causes a lump to develop in the throat. The lump will move up and down when you swallow.

Types of goitre

There are two different types of goitre:

• diffuse small goitre - where your entire thyroid gland swells to a larger size and feels smooth to the touch
• nodular goitre - where certain sections, or 'nodules', of your thyroid gland swell and feel lumpy to the touch

Other symptoms

Other associated symptoms of a goitre can include:

• coughing
• a tight feeling in your throat
• changes to your voice, such as hoarseness
• less commonly, difficulty swallowing (dysphagia) or difficultly breathing, such as a high-pitched sound when you breathe (stridor)

Causes

In some cases, no definite cause for goitres can be identified. However, there are a number of different possible causes that are outlined below.

Iodine deficiency

Iodine deficiency used to be the major cause of goitres, and it still remains a significant problem in parts of the developing world.

Iodine is a trace element that is found in seawater and soil. It enters the food chain through plants that grow in iodine-rich soil, or through fish or plants from the sea. Iodine is found in:

• seafood, such as fish, shellfish or seaweed
• plant foods, such as cereals or grains
• cow’s milk

The thyroid gland (a gland in the neck that produces hormones) needs iodine to help manufacture thyroid hormones (chemicals released into the bloodstream that control the body's growth and metabolism). If your body does not receive enough iodine, your thyroid gland will expand in order to produce more thyroid hormones.

In the UK, iodine deficiency used to be a common problem until, in the early 1900s, salt manufactures started to add small amounts of iodine to salt, which reduced the number of cases.

However, in recent years, the number of people experiencing iodine deficiency in the UK has started to rise. This could be due to an increased number of people preferring a low-salt, non-dairy diet. Iodine deficiency can be a problem for people who are following a strict vegan diet.

Over-active thyroid gland

A goitre can develop if the thyroid gland becomes over-active (hyperthyroidism), leading to an excessive amount of thyroid hormones being produced. Increased hormone production over-stimulates the thyroid gland and causes it to swell.

The leading cause of hyperthyroidism is a condition called Graves' disease. Graves' disease causes your immune system (the body’s natural defence system) to send antibodies (proteins that fight infections) to your thyroid gland. The antibodies attack the thyroid gland, causing an increased amount of thyroid hormones to be released.

See the Heath A-Z topic about Hyperthyroidism for more information about this condition.

Under-active thyroid gland

A goitre can also develop if the thyroid gland becomes under-active (hypothyroidism). If the thyroid gland does not produce enough thyroid hormones, the body will stimulate the gland to produce more. This can cause the thyroid gland to swell.

As well as iodine deficiency, one of the leading causes of hypothyroidism is a condition called Hashimoto's thyroiditis, which is sometimes also known as Hasimoto's disease.

As with Graves' Disease, Hashimoto's thyroiditis causes the immune system to attack the thyroid gland. Rather than over-stimulating the gland, Hashimoto's thyroiditis interferes with the gland's ability to produce hormones. In order to compensate for this, the body causes the gland to swell, resulting in a goitre.

See the Health A-Z topic about Hypothyroidism for more information about this condition.

Smoking

There may also be a link between smoking and an increased risk of developing a goitre. This may be because tobacco smoke contains a chemical called thiocyanate, which can interfere with the body's ability to make use of iodine.

Smokers who have a low-iodine diet are particularly at risk. See the Health A-Z topic about Quitting smoking for information and advice about how to stop smoking.

Other causes

A number of other causes have been linked to goitres. These are outlined below.

Pregnancy and puberty

The changes in hormone levels that occur during pregnancy and puberty (when a child gradually progresses to a sexually developed adult) can affect the thyroid gland.

Lithium

Lithium is a medicine that is often used to treat a number of mental health conditions, such as depression and bipolar disorder (a condition that affects your moods, which can swing from one extreme to another). Lithium can interfere with how your thyroid gland functions.

Infection

A number of bacteria, parasites, and fungi that cause infections are also known to cause goitres.

Goitrogenic foods

Goitrogenic foods are foods that if eaten in excess are known to suppress the function of the thyroid gland. They include:

• spinach
• peanuts
• soybeans
• tofu

Excessive iodine

An excessive amount of iodine can build up in the body as a result of eating an excessive amount of iodine-rich food. For example seaweed, particularly kelp (a type of brown seaweed that contains many different minerals), is a rich source of iodine. An excess amount of iodine can affect the thyroid gland.

Exposure to radiation

Exposure to radiation (energy waves that travel through the air) can sometimes cause goitres. Radiation is used to treat some health conditions (radiotherapy), such as cancer. Receiving radiotherapy to the neck can sometimes cause goitres.

Non-cancerous growths

Non-cancerous growths can also sometimes cause goitres.

Thyroid cancer

Thyroid cancer is another possible cause of goitres, although it is rare in the UK. Cancer research UK estimate that six out of every 1,000 cancers diagnosed in the UK are thyroid cancer.

See the Health A-Z topic about Thyroid cancer for more information about this condition.

Diagnosis

If you have a goitre, your GP will carry out a physical examination of your neck, and may test your thyroid gland (a gland in your neck that produces hormones) to see how well it is working.

Physical examination

Your GP will examine your neck to assess the size and extent of any swelling, and determine whether it is:

• a diffuse small goitre - where your entire thyroid gland swells up
• a nodular goitre - where certain sections, or 'nodules', of your thyroid gland swell up

They may also ask you to swallow to see whether the lump moves up and down as you do.

Your GP may arrange for a thyroid function test in order to discover the underlying cause of your goitre.

Thyroid function test

A thyroid function test measures the level of certain hormones (chemicals produced by the body) in your blood.

The thyroid gland produces two hormones:

• thyroxine
• triiodothyronine

An excessive amount of these two hormones would indicate an underlying condition that is making your thyroid gland over-active, such as Graves' disease (an autoimmune condition that causes your body to attack itself).

If your thyroid gland is under-active, your pituitary gland (a pea-sized gland that sits below the brain) will produce a hormone called thyroid stimulating hormone (TSH).

TSH is released by your body in order to stimulate your thyroid gland. A high level of TSH in your blood would indicate that your thyroid gland is under-active.

Further tests

If you are referred to a specialist (see box to the right), you may have some further tests that are carried out in hospital. These are described in more detail below.

Radioactive iodine scan

During a radioactive iodine scan, a small amount of radioactive iodine is injected into your vein. The iodine then builds up in your thyroid gland and can be studied using a special camera.

The scan can provide more information about the structure and function of your thyroid gland. The amount of radiation that is used is perfectly safe for most people, although it may not be suitable if you are pregnant.

Ultrasound scan

An ultrasound scan is a procedure that uses high frequency sound waves to create an image of part of the inside of your body. It can be used to:

• build up a picture of the inside of your thyroid gland
• assess the size of your thyroid gland
• check if there are any enlarged nodules in your thyroid gland that have not been found during the physical examination

See the Health A-Z topic about Ultrasound scans for more information about this procedure.

Fine needle aspiration

Fine needle aspiration is a procedure that is used to extract a sample of the goitre (biopsy) to test the cells inside it.

During the procedure, a fine needle on the end of a syringe will be inserted into the goitre in your throat. A sample of the fluid or tissue inside the goitre will be sucked through the needle and into the syringe. The sample will be examined under a microscope in order to determine what kind of cells are inside the goitre. 

Treatment

If you have a goitre, the treatment that you receive will depend on:

• the size of the goitre
• any associated symptoms that the goitre is causing
• whether you have any underlying health conditions, such as an overactive or underactive thyroid gland (a gland in your neck that produces hormones)

If tests reveal that your thyroid gland is working normally, and the goitre is small, no immediate treatment may be recommended. Your condition may just be monitored.

If you have a problem with your thyroid gland, it will be treated. If treating the underlying cause of your goitre does not improve your condition, you may need to have surgery. One study estimated that up to one in seven people with goitres may eventually require surgery. 

Underactive thyroid gland

If testing reveals that you have an underactive thyroid gland, one treatment option involves using a synthetic (man-made) hormone to replicate your normal thyroid function. This is called hormone therapy.

The synthetic hormone, which is called levothyroxine, is taken orally (by mouth), usually once a day.

Side effects of levothyroxine include:

• chest pain
• an irregular or rapid heart beat
• muscle cramps (when your muscles suddenly shorten, causing pain)
• muscle weakness
• vomiting
• diarrhoea
• weight loss
• problems sleeping
• headaches
• shaking (tremors)
• sweating

These side effects should pass in a few days as your body starts to get used to the hormone. However, if they continue you should speak to your GP because your dosage may need to be adjusted. In most cases, hormone therapy will need to be maintained for the rest of your life.

See the Health A-Z topic about Hypothyroidism - treatment for more information about treating this condition.

Overactive thyroid gland

If you have an overactive thyroid gland, there are several different treatments that may be recommended. Some are of these are described below.

See the Health A-Z topic about Hyperthyroidism - treatment for more information about treating this condition.

Thionamides

If you have an over-active thyroid gland, you may be given medicines called thionamides. Thionamides help to reduce the amount of thyroid hormones that your thyroid gland is producing.

Thionamides are usually taken orally (by mouth). The medicine works by gradually reducing the levels of thyroid hormones, so it may be several weeks before you notice any effects.

Side effects of thionamides include:

• a mild skin rash
• pain in your joints
• nausea (feeling sick)
• itchy skin

In very rare cases, thionamides can cause a serious condition called agranulocytosis (a sudden drop in the number of white blood cells). If this occurs, it will usually be during the first three months of treatment.

You should seek urgent medical attention if you are taking a thionamide and you develop:

• a high temperature (a fever) of 38C (100.4F) or above
• sore throat
• mouth ulcers
• other signs of infection, such as a rash or swelling

You may need to take thionamides for two to four months before your thyroid gland is under control.

Radioactive iodine

Radioactive iodine is another treatment for an over-active thyroid gland that is taken orally (by mouth). When the iodine reaches your thyroid gland, it destroys the thyroid cells and reduces the size of the goitre. However, the treatment may cause your thyroid gland to become under-active. If this happens, you may need to have hormone therapy (see above).

Iodine supplements

Your GP may recommend iodine supplements if your goitre is caused by an iodine deficiency.

Iodine supplements are also available in many health food shops without prescription. However, you should always consult your GP before taking them. This is because the amount of iodine that is needed by the body varies from person to person. Taking too much iodine may cause other health problems and it could also have toxic (poisonous) effects.

Surgery

If your goitre is interfering with your breathing, or swallowing, and it has not responded to other forms of treatment, surgery may be required to remove part, or all, of your thyroid gland.

You will be given a general anaesthetic, so you will be unconscious and unable to feel anything. 

During surgery, the surgeon will make an incision (cut) in the front of your neck so that they can see your thyroid gland. They will usually remove half of your thyroid gland. This should reduce the amount of thyroid hormones being produced, and reduce the size of your goitre.

The surgeon will attempt to remove enough of your thyroid gland to relieve your symptoms, while leaving enough so that normal thyroid hormone production can continue. However, in some cases, this is not always possible and you may require hormone therapy following surgery.

Surgery to remove the thyroid gland is usually safe, but as with all surgical procedures, there is a risk of complications, such as post-operative infection. Some other possible complications are briefly described below.

Nerve damage

The thyroid gland is very close to the two laryngeal nerves (the nerves that control your vocal cords). If these are accidentally damaged during surgery you could:

• have a temporary or permanently hoarse voice
• not be able to speak
• have difficulty breathing

Some studies have found that permanent damage to the laryngeal nerves affects one or two people in every 100 who have this type of surgery. Temporary damage may affect up to five people in every 100.

Parathyroid gland damage

The parathyroid glands are glands that help to regulate the amount of calcium (a mineral that is needed for strong teeth and bones) in your body. If the parathyroid glands are damaged, you will probably need to take calcium supplements for the rest of your life.

The risks of complications occurring after thyroid gland surgery are estimated to be 1-2%.