A goitre is an enlarged thyroid gland. Some people with a goitre (but not all) have an underactive or overactive thyroid. This means that they make too much or too little thyroid hormone. There are various causes of goitre and treatment depends on the cause.
What is a goitre?
A goitre is an enlarged thyroid gland. A goitre can mean that all the thyroid gland is swollen or enlarged, or one or more swellings or lumps develop in a part or parts of the thyroid.
The thyroid gland is in the lower part of the front of the neck. It lies just in front of the windpipe (trachea). It has a right and left lobe which are connected together by a narrow band of thyroid tissue. It is roughly the shape of a butterfly. You cannot usually see or feel a normal thyroid gland. If the thyroid enlarges, it causes a swelling in the neck which you can see - a goitre.
The thyroid gland makes thyroid hormones - called thyroxine (T4) and triiodothyronine (T3). These hormones are carried round the body in the bloodstream. Thyroxine and T3 help to keep the body's functions (the metabolism) working at the correct pace. Many cells and tissues in the body need thyroxine and T3 to keep them working correctly.
Types of goitre
There are different types of goitre, each with various causes.
Diffuse smooth goitre
This means that the entire thyroid gland is larger than normal. The thyroid feels smooth but is larger than normal.
There are a number of causes. For example:
- Graves' disease - an autoimmune disease which causes the thyroid to swell and make too much thyroxine. In autoimmune disorders your body produces proteins called antibodies which damage a different part of your body - in this case, your thyroid.
- Inflammation of the thyroid (thyroiditis) - which can be due to various causes. For example, another autoimmune condition called Hashimoto's thyroiditis can damage the thyroid gland. Infections with germs such as bacteria and viruses can cause different types of thyroiditis. Radiotherapy treatment to the neck can also lead to inflammation of the thyroid.
- Iodine deficiency. The thyroid needs iodine to make thyroxine and T3. If you lack iodine in your diet, the thyroid swells as it tries to make enough thyroxine and T3.
- Some medicines such as lithium and amiodarone can cause the thyroid to swell as a side-effect.
- Hereditary factors - some people inherit a tendency for a thyroid to swell. In particular, it may swell at times of life when you may make more thyroxine and T3 - for example, when you are pregnant, or during puberty.
- Any other disorder which causes problems in the making of thyroxine or T3 may cause the thyroid to swell.
A thyroid nodule is a small lump which develops in the thyroid. There are two types:
- A multinodular goitre. This means the thyroid gland has developed many lumps or nodules. The thyroid gland feels generally lumpy.
- A single nodule. Causes include:
- A cyst. This is a non-cancerous sac-like swelling filled with fluid.
- An adenoma. This is a solid non-cancerous tumour.
- A cancerous tumour (rare).
- Other rare causes.
Goitres and production of thyroid hormones
- In many people with a goitre, the goitre does not affect the amount of thyroid hormones that you make. You are then euthyroid, which means you make the correct amount of these hormones.
- In some people, the goitre is associated with an abnormality of thyroid function. You may make too much thyroid hormone (hyperthyroidism or overactive thyroid) or too little (hypothyroidism or underactive thyroid).
Note: you can also develop an overactive or underactive thyroid without having a goitre.
What are the symptoms of a goitre?
- In many cases there are no symptoms apart from the appearance of a swelling in the neck. The size of a goitre can range from very small and barely noticeable, to very large.
- Most goitres are painless. However, an inflamed thyroid (thyroiditis) can be painful.
- If your thyroid makes too much or too little thyroxine or T3, this can cause a range of symptoms. See separate leaflets called Hyperthyroidism (Overactive Thyroid) and Hypothyroidism (Underactive Thyroid) for more details.
- A large goitre may press on the windpipe (trachea) or the gullet (oesophagus). This may cause difficulty with breathing or with swallowing.
A multinodular goitre
Side view of a goitre
Assessing the situation
When you have a goitre, a doctor will usually do some blood tests to check if you are making too much or too little thyroxine or T3. Blood tests may also help to find out the cause of some goitres. Other tests may be done to find out the cause of the goitre. For example:
- An ultrasound scan of the thyroid. This is the best test for thyroid swellings. An ultrasound scan is a safe and painless test which uses sound waves to create images of organs and structures inside your body. It can tell if a nodule is a cyst or a solid lump.
- A small piece of tissue (a biopsy) may be taken from a nodule to look at under the microscope. The biopsy is done by inserting a thin needle into the nodule. It is a simple and safe procedure. The specialist doing the biopsy can see where they are inserting the needle by doing an ultrasound scan at the same time.
- Occasionally other specialist blood tests are needed to help establish the cause. Occasionally a CT scan or an MRI scan is needed.
What is the treatment for a goitre?
Treatment depends on the cause, the size of the goitre, and whether it is causing symptoms. For example:
- If you have a small goitre that is not due to a cancerous nodule, and your thyroid is making the correct amounts of thyroid hormones then you may not need any treatment.
- You will need treatment if you make too much or too little of your thyroid hormones.
- An operation to remove some or all of the thyroid may be an option in some cases.
- Radioactive iodine treatment may be an option for a goitre causing an overactive thyroid:
- This involves taking a drink, or swallowing a capsule, which contains radioactive iodine.
- The radioactive iodine builds up in the thyroid gland.
- As the radioactivity is concentrated in the thyroid gland, it destroys some thyroid tissue.
- You may need to take thyroxine tablets after having radioactive iodine, if too much of the thyroid is destroyed.
- If you have cancer of the thyroid, you will probably need an operation to remove the cancer and some of the thyroid gland.
- Iodine replacement is given if the goitre is due to lack of iodine in the diet.
Dr Tim Kenny
Dr Mary Harding
Dr John Cox