A goitre (sometimes spelt "goiter") is an abnormal swelling of the thyroid gland that causes a lump to form in the neck.
There can be many possible causes, including an under- or overactive thyroid gland, iodine deficiency and, rarely, thyroid cancer (see below).
The thyroid gland
The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). It produces thyroid hormones, which help regulate the body's metabolism (the chemical processes that occur in the body).
The thyroid gland isn't usually noticeable, but if it swells, it produces a lump on the neck known as a goitre.
The size of a goitre can vary from person to person. In most cases, the swelling is small and doesn't cause any symptoms. However, in more severe cases, the swelling can increase significantly and affect breathing and swallowing.
What causes a goitre?
Goitres can have several possible causes, including:
an overactive thyroid gland (hyperthyroidism)
an underactive thyroid gland (hypothyroidism)
pregnancy and the menopause
a lack of iodine (a trace mineral found in milk and fish) in the diet
Diagnosing a goitre
If you think you have a goitre, see your GP – they can carry out some tests to determine whether you have one.
Your GP will examine your neck to see whether your thyroid gland is swollen. They may also refer you for a thyroid function test, to see how well your thyroid gland is working.
A thyroid function test measures the level of certain hormones (chemicals produced by the body) in your blood. It can show whether you have an underactive or overactive thyroid, both of which are associated with goitre.
Treating a goitre
The treatment for goitres depends on the underlying cause. If the goitre is small and isn't causing any problems, a wait-and-see approach is usually recommended.
Other possible treatments include radioiodine treatment and thyroid surgery.
Although most goitres are usually benign (non-cancerous), it's estimated that in 1 in 20 cases they may be a sign of thyroid cancer.
Goitres can affect anyone, but they're more common in women and people over 40.
Risk factors for goitres include:
sex – women are more likely to have thyroid problems and develop a goitre
age – the risk of developing a goitre increases with age
a lack of iodine in the diet
pregnancy and menopause – for reasons that are unclear, the risk of having thyroid problems increases during pregnancy and the menopause
medication – some types of medication, such as lithium and immunosuppressants, increase your risk
exposure to radiation – having radiation treatment to your neck or chest area, or being exposed to radiation, also increases your risk
Symptoms of goitre
The main symptom of a goitre is swelling of the thyroid gland, which causes a lump to develop in the front of the neck.
The lump will move up and down when you swallow.
Types of goitre
There are two main types of goitre:
Other associated symptoms can include:
Less commonly, you may also have:
diffuse goitre – where the entire thyroid gland swells and feels smooth to the touch
nodular goitre – where solid or fluid-filled lumps called nodules develop within the thyroid and make the thyroid gland feel lumpy to touch; the nodules can be single or multiple
a tight feeling in your throat
changes to your voice, such as hoarseness
difficulty swallowing (dysphagia)
difficulty breathing – there may be a high-pitched sound when you breathe (stridor)
Causes of goitre
Goitres can have many possible causes. Sometimes, a cause can't be identified.
Iodine deficiency used to be the primary cause of goitre, but dietary changes mean it's now rare in the UK. However, it remains a significant problem in parts of the developing world.
Iodine is a trace element 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:
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 doesn't receive enough iodine, your thyroid gland becomes underactive and increases in size, in order to produce more thyroid hormones.
Until the early 1900s, iodine deficiency used to be a common problem in the UK. Around this time, salt manufacturers started adding 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 preference for a low-salt, non-dairy diet. Iodine deficiency can be a problem for people who follow a strict vegan diet (where meat, eggs, dairy foods and all other animal-derived products are excluded).
Overactive thyroid gland
A goitre can develop if the thyroid gland becomes overactive (hyperthyroidism), resulting in too much thyroid hormone 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. This causes your immune system (the body’s natural defence system) to send antibodies (proteins that fight infections) to your thyroid gland. The antibodies stimulate the thyroid gland, causing an increased amount of thyroid hormones to be released.
Underactive thyroid gland
A goitre can also develop if the thyroid gland becomes underactive (hypothyroidism). If the thyroid gland doesn't produce enough thyroid hormones, your body will stimulate it 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 known as Hashimoto's disease.
As with Graves' disease, Hashimoto's thyroiditis is an autoimmune condition. However, rather than over-stimulating the gland, it causes inflammation within the thyroid gland and interferes with its ability to produce hormones. To compensate for this, the body causes the gland to swell, resulting in a goitre.
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 utilise iodine.
People who smoke and have a low-iodine diet are particularly at risk.
Many other causes have been linked to goitres, which are outlined below.
Pregnancy, the menopause and puberty
The changes in hormone levels that occur during pregnancy, the menopause and puberty (sexual maturation) can affect the thyroid gland.
Lithium is a medicine that's 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.
The thyroid gland can become inflamed. This condition is known asthyroiditis, and it can sometimes occur after pregnancy, as a result of certain viral and bacterial infections, or after taking certain medications. Thyroiditis can cause a painful goitre to develop.
Too much iodine can build up in the body as a result of eating too much iodine-rich food. Seaweed, for example, particularly kelp, is a rich source of iodine. Having too much in the body can affect the thyroid gland.
Radiation exposure can sometimes cause goitres. Radiation, in the form of radiotherapy, is often used to treat certain health conditions, such as cancer. Having radiotherapy to the neck can sometimes cause goitres.
Nodules within the thyroid
Single or multiple nodules within the thyroid gland can cause goitres. Most thyroid nodules are benign (non-cancerous), but all nodules need to be assessed thoroughly to exclude thyroid cancer (see below).
Thyroid cancer is another possible cause of goitres, although it's rare in the UK. Cancer Research UK estimates that less than 1 in every 100 cancers diagnosed in the UK is thyroid cancer.
seafood, such as fish, shellfish or seaweed
plant foods, such as cereals or grains
If you think you have a goitre, see your GP. They can examine your neck to see if there's any evidence of thyroid gland swelling.
Blood tests to check how well your thyroid gland is working may also be carried out.
Your GP will examine your neck to assess the size and extent of any swelling and determine whether it's:
a diffuse goitre – where your entire thyroid gland swells up and feels smooth
a nodular goitre – where solid or fluid-filled nodules develop within the thyroid, making the thyroid gland feel lumpy
They may ask you to swallow, to see whether the lump moves up and down.
Your GP may also arrange for you to have a thyroid function test to determine 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 test can show if you have an underactive or overactive thyroid gland, both of which are associated with goitre.
The thyroid gland produces two hormones – thyroxine and triiodothyronine. An excessive amount of these two hormones indicates an underlying condition that's making your thyroid gland overactive, such as Graves' disease (an autoimmune condition that causes antibodies to stimulate the thyroid gland).
If your thyroid gland is underactive, 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 to stimulate your thyroid gland. A high level of TSH in your blood indicates that your thyroid gland is underactive.
If you're referred to a specialist, you may have further tests in hospital. These are described in more detail below.
Radioactive iodine scan
This involves a small amount of radioactive iodine being injected into your vein. The iodine builds up in your thyroid gland, which can then be studied using a special camera.
The scan can provide useful information about the structure and function of your thyroid gland. As the amount of radiation used is very small, it's perfectly safe for most people. However,it may not be suitable if you're pregnant.
An ultrasound scan 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 whether there are any enlarged nodules in your thyroid gland not found during the physical examination
Fine-needle aspiration is a procedure where a sample of the goitre is extracted, so that the cells inside it can be tested. This procedure is often known as a biopsy.
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 to determine what kind of cells are inside the goitre.
Your GP may refer you to a specialist thyroid clinic or an endocrinologist (a specialist in hormone-related conditions), if you have a thyroid swelling and:
it's getting bigger
you have a family history of thyroid cancer
you've had radiation treatment to your neck
you have swollen lymph nodes in your neck
you're a child or teenager
you're 65 or over
your voice has changed
you're making a high-pitched noise as you breathe (stridor)
you're having difficulty breathing or swallowing
Treatment for goitre can include medication, hormone therapy and surgery.
The treatment you receive will depend on:
the size of the goitre
the symptoms the goitre is causing
whether you have any underlying conditions, such as an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland (hypothyroidism)
If tests reveal your thyroid gland is working normally, and the goitre is small, no immediate treatment may be necessary and your condition may just be monitored.
If you have a problem with your thyroid gland, however, it will be treated. Surgery may be needed if your condition doesn't improve with treatment. A study has estimated that up to one in seven people with goitres may eventually require surgery.
Underactive thyroid gland
If tests reveal that you have an underactive thyroid gland, treatment could include using a synthetic hormone to replicate your normal thyroid function (hormone therapy).
The synthetic hormone is levothyroxine and is taken orally, usually once a day.
Side effects of levothyroxine, which usually occur when too much has been taken, can include:
an irregular or rapid heartbeat (palpitations)
muscle cramps (when your muscles suddenly shorten, causing pain)
These side effects should pass in a few days as your body gets used to the hormone. However, if they continue, speak to your GP as your dosage may need to be adjusted. In most cases, hormone therapy will need to be carried out for the rest of your life.
Overactive thyroid gland
If you have an overactive thyroid gland, there are several recommended treatments. Some are described below.
Thionamides are a type of medication that help reduce the amount of hormones your thyroid gland is producing.
Thionamides are usually taken orally. They work by gradually reducing levels of thyroid hormones, so it may be several weeks before you notice any effects.
Side effects of thionamides include:
a mild skin rash
nausea (feeling sick)
In very rare cases, thionamides can cause a serious condition called a sudden drop in the number of white blood cells (agranulocytosis). This usually occurs within the first three months of treatment.
Signs to look out for include:
a high temperature (fever) of 38°C (100.4°F) or above
If you notice any of the above, see your GP.
You may need to take thionamides for two to four months before the overactive thyroid gland is controlled.
Radioactive iodine is another treatment for an overactive thyroid gland that's taken orally. When the iodine reaches your thyroid gland, it destroys the thyroid cells and reduces the goitre's size.
However, the treatment may cause your thyroid gland to become underactive. If this happens, you may need hormone therapy (see above).
A well-balanced diet usually provides all the iodine your body needs, and iodine supplements aren't usually required in developed countries like the UK. Your GP can give more advice about extra supplements, if needed.
Iodine supplements are available in many health food shops without a prescription. However, always consult your GP before taking them, because the amount of iodine needed varies from person to person. Taking too much iodine may cause other health problems, and it could also have toxic (poisonous) effects.
If your goitre is interfering with your breathing or swallowing, and it hasn't responded to other forms of treatment, you may need surgery to remove part or all of your thyroid gland. This procedure is known as a thyroidectomy.
You will be given a general anaesthetic, meaning you will be unconscious and unable to feel anything.
During surgery, the surgeon will make an incision in the front of your neck so they can see your thyroid gland.
How much of the thyroid gland is removed will depend on the underlying condition causing the goitre. The procedure will reduce the size of your goitre and the amount of thyroid hormones being produced.
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, if this isn't possible, you may require hormone therapy after surgery.
Surgery to remove the thyroid gland is usually safe, but as with all surgical procedures there's a risk of complications, such as post-operative infection.
The risks of complications occurring after thyroid gland surgery are estimated to be 1-2%. Before having the procedure, you should discuss the risks with your surgeon.
Nerve damage and parathyroid gland damage are two other possible complications of thyroid gland surgery. These are briefly described below.
The thyroid gland is very close to the two laryngeal nerves, which control your vocal cords. If these are accidentally damaged during surgery, your voice and breathing could be affected.
Permanent damage to the laryngeal nerves affects one to 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 help regulate the amount of calcium in your body. If the parathyroid glands are damaged, you will probably need to take calcium supplements for the rest of your life.