Goitre

A goitre is an enlargement of the thyroid gland. The thyroid sits at the front of the throat, just below the Adam’s apple (larynx). It has two lobes that lie on either side of the windpipe and are joined at the front by a bridge of tissue called the isthmus.

The thyroid releases hormones that regulate many of the body’s metabolic processes, including growth and how energy is used. It is controlled by the pituitary gland in the brain. The pituitary prompts the thyroid to make its hormones - mainly thyroxine (T4) and tri-iodothyronine (T3) - by releasing thyroid-stimulating hormone (TSH).

The thyroid cannot make these hormones without enough iodine from the diet. When the diet is low in iodine, the pituitary keeps signalling the thyroid, but the gland cannot respond properly. It enlarges as it tries to keep up with the demand.

Symptoms#

The signs of a goitre depend on its size. They can include:

• Swelling at the front of the throat, ranging from a small lump to a large mass
• Difficulty swallowing, if the goitre is large enough to press on the food pipe (oesophagus)
• Difficulty breathing, if the goitre presses on the windpipe (trachea)

What causes a goitre#

A goitre can result from a range of factors, including:

• Too little iodine in the diet
• A high intake of certain foods that interfere with iodine use, such as cabbage, broccoli and cauliflower; soy may also play a role
• Certain medicines, such as lithium and phenylbutazone
• Thyroid nodules
• Thyroid cancer
• Hyperthyroidism (overactive thyroid)
• Hypothyroidism (underactive thyroid)

Two broad types#

Goitres are often grouped into two types:

• Endemic goitre, where a whole community is affected by a lack of dietary iodine. This often happens where the soil that food is grown in is low in iodine. Mountainous regions and areas far from the sea are most likely to have iodine-poor soil. Endemic goitre is more common in developing countries and is rare where iodine supplementation is widespread.
• Sporadic goitre, where only the individual is affected. Risk factors include family history, diet, being over 40 years of age, and gender, as women are more susceptible than men.

Hyperthyroidism#

Hyperthyroidism means the thyroid is overactive. A common cause is Graves’ disease, in which the immune system makes antibodies that act like TSH and stimulate the thyroid uncontrollably. The gland responds by producing too much hormone, and this heavy overstimulation can cause a goitre.

Symptoms of hyperthyroidism can include a racing or irregular heartbeat, restlessness, unexplained weight loss, intolerance of heat and diarrhoea.

Hypothyroidism#

Hypothyroidism means the thyroid is underactive. The pituitary keeps signalling the thyroid to make hormones, and the gland enlarges as it tries to comply. Besides iodine deficiency, causes include Hashimoto’s disease (an autoimmune condition, like Graves’ disease), treatment for hyperthyroidism, and problems with the pituitary gland.

Symptoms of hypothyroidism can include low energy, depression, intolerance of cold and constipation.

Thyroid nodules#

Nodules are lumps that grow on the gland. They fall into two groups:

• Hot or warm nodules account for around 15 per cent of cases and can cause hyperthyroidism. Their cancer risk is low.
• Cold nodules account for around 85 per cent of cases. Around 20 per cent of these are cancerous.

Thyroid cancer#

Sometimes the thyroid is enlarged because of cancer. Anyone can develop thyroid cancer, regardless of age or gender. The rates are very low and the cure rate is very good. Risk factors include:

• Chronic goitre, or long-standing enlargement of the gland
• Family history, as a susceptibility can be inherited
• Gender, as more women than men develop thyroid cancer
• Past exposure to high doses of radiation

How it is diagnosed#

A goitre and its underlying cause may be assessed using:

• A physical examination
• Blood tests to check thyroid hormone levels and particular antibodies
• An ultrasound scan
• A radioactive iodine scan
• A fine needle biopsy

Treatment#

Treatment depends on the underlying cause:

• A goitre due to iodine deficiency can be helped by adding iodine-rich foods to the diet, such as seafood and iodised salt.
• Hyperthyroidism is managed with medicines that slow the thyroid. If these do not work, part or all of the gland may be surgically removed, or the hormone-producing cells may be destroyed with radioactive iodine treatment.
• Hypothyroidism is treated with lifelong hormone replacement therapy.
• Benign nodules may be shrunk with medicines, destroyed with radioactive iodine treatment or removed surgically, depending on the type.
• Thyroid cancer is treated by surgically removing the gland, followed by radioactive iodine treatment.

Key points#

• Symptoms of a goitre include swelling at the front of the throat, ranging from a small lump to a large mass.
• A goitre can be caused by heavy overstimulation of the thyroid gland.
• Symptoms of hypothyroidism include low energy, depression, cold intolerance and constipation.
• Nodules fall into two groups, and sometimes the thyroid is enlarged because of cancer.
• Endemic goitre often occurs where the soil that food is grown in is low in iodine.

Where to get help#