Enlarged thyroid

Development of a goitre

An enlarged thyroid gland is known as a goitre. There are many causes, including a shortage of iodine in the diet which occurs in remote mountainous parts of the world, drugs such as lithium carbonate (Priadel) used to treat patients with bipolar disorder, and autoimmune disorders such as Hashimoto’s thyroiditis and Graves’ disease.

The cause of most goitres in this country is not known, however. Such goitres are called ‘simple goitres’ despite the fact that there are almost certainly complex reasons for their development. Although the thyroid gland is enlarged it continues to produce normal amounts of hormones and the patient is referred to as ‘euthyroid’ as opposed to hyperthyroid or hypothyroid.

 

At first, in teenagers and young adults, the goitre is evenly or diffusely enlarged. During the next 15 to 25 years, whatever caused the thyroid to grow abnormally in the first place remains and it continues to grow but becomes full of lumps or nodules. By the time the young person reaches middle age, the goitre will have become lumpy, when it is known medically as a ‘multinodular goitre’.

 

Simple diffuse goitre

Most of those who have a simple diffuse goitre are young women between the ages of 15 and 25. If you are one of them, you (or your relatives) will have noticed a symmetrical, smooth swelling in the front of your neck. You may have had it for some years but thought it was just ‘puppy fat’. The goitre will move up and down when you swallow. It is not tender, however, and does not usually cause difficulty in swallowing but you may experience a tight sensation in your neck.

 

The goitre may vary slightly in size and be more noticeable at the time of a period or during pregnancy. It isn’t normally a problem appearance-wise – quite the opposite as far as some people are concerned. For example, the great seventeenth and eighteenth century artists often added a goitre to the female figure to enhance her beauty!

 

Confirming the diagnosis

Usually your GP will want you to be seen by a specialist to exclude the rarer causes of goitre. He or she can normally do this by feeling your neck and by taking blood tests.

 

Treatment

No treatment is necessary. In the past iodine (often added to milk) or thyroxine tablets were given but neither is effective. Many people find that their goitre becomes less noticeable or even disappears over a period of two to three years.

 

Simple multinodular goitre

If you are in your 40s or 50s, you will probably first become aware of a swelling in your neck while washing or applying make-up in front of a mirror. In fact, the goitre will have been present for many years but has now reached a critical size, or it may be that your neck has become thinner.

 

The goitre is often more obvious on one side of the neck than the other. It may vary in size from being barely visible to other people to so large that you feel you have to hide it by wearing scarves or high-necked sweaters.

 

A few people notice the enlarged thyroid gland for the first time because internal bleeding causes increased swelling which is accompanied by discomfort in the neck, like a bruise, lasting a few days.

 

If the goitre is large there may be difficulty in swallowing dry, solid food and, if the trachea (windpipe) is squashed to any extent, there may be difficulty in breathing; singers, in particular, will notice a change in their voice.

 

Confirming the diagnosis

Your GP may take a blood sample to check that your thyroid hormone levels are normal but will usually ask a specialist for advice about further investigations and treatment. The specialist may wish to carry out one or more of the following tests.

 

X-ray and breathing tests

These will reveal whether the goitre is compressing or squashing the windpipe.

 

Ultrasound scan

A probe, the size of a small hand torch, is passed over the skin of the front of the neck and an image of the goitre is formed on a screen. As well as showing its size and extent it will also highlight any cysts or nodules that the specialist may not have noticed by examining the neck.

 

Isotope scan

This technique provides a different type of image which shows whether the nodules in the goitre are likely to be producing thyroid hormones, in which case the development of an overactive thyroid is more likely in future years. It is obtained by injecting a tiny amount of radioactivity in the form of a radioactive substance called technetium-99m into a vein. About half an hour after the injection you lie under a sophisticated form of camera for a few minutes.

 

Fine needle aspiration

This involves attaching a needle of the same size as that used for taking a blood sample to the end of a syringe, then, while you’re lying down, passing it without local anaesthetic through the skin of the neck into the enlarged thyroid gland. If the nodule is very small, the procedure may be carried out with the help of ultrasound to ensure that the needle is in the correct place.

 

The discomfort is no more than that felt during straightforward blood tests. By pulling on the plunger and moving the needle up and down a tiny distance within the goitre, the doctor can obtain thyroid cells for analysis. These are smeared on to a glass slide and, after processing in the pathology laboratory, are examined under a microscope. The appearance of the cells will help to determine whether the thyroid enlargement is the result of a malignant tumour.

 

Fine needle aspiration, commonly known as FNA, is not often carried out in patients with a multinodular goitre unless the gland is very much bigger on one side than the other, or the goitre is growing very rapidly.

 

Treatment

If your goitre is relatively small, you probably won’t need any treatment. Your GP will check thyroid hormone levels in your blood every one to two years as there is a possibility of the gland becoming overactive and causing hyperthyroidism at some stage during the next 20 years or so. Although thyroxine tablets are prescribed in certain parts of the world in an attempt to shrink the goitre, they are of little or no benefit and may cause hyperthyroidism.

 

Surgery

If the goitre becomes so large that it looks really unattractive or is compressing the windpipe, the most effective treatment is an operation to remove most of the thyroid gland. No treatment is necessary before surgery and you’ll be in hospital for about three days. The complications are the same as those for surgery for Graves’ disease. You may have to take thyroxine treatment afterwards as there may be insufficient thyroid tissue left to produce adequate amounts of hormones.

 

Radioactive iodine

In patients who aren’t fit enough for surgery or who don’t want to have an operation, it may be possible to reduce the size of the goitre by about 50 per cent by giving radioactive iodine. A large dose is necessary, and you may have to be admitted to hospital for 24 to 48 hours. If so, you’ll be given a single room to avoid contaminating other patients and visitors with radioactivity.

 

It may take several months for the goitre to shrink. It is unlikely that the thyroid will become underactive because the radioactive iodine is mainly concentrated within the nodules and, as they become smaller, the thyroid tissue surrounding them that has been dormant and unaffected by the radiation wakes up and starts to produce thyroid hormones.

 

Case history: Jenny

Jenny Morris was a single woman in her seventies who had been an accomplished actress. She always wore a silk scarf around her neck, day and night, summer and winter. Friends and neighbours thought it was part of her slightly eccentric personality, but when she was admitted to hospital as an emergency with abdominal pain due to gallstones the scarf was removed to reveal a large goitre and a scar from a previous thyroid operation.

 

Miss Morris explained that the operation had been carried out for a goitre when she was quite young. In her mid-forties the goitre appeared again but she was told further surgery was out of the question because a second operation was technically more difficult and any damage to the nearby nerve supply to the voice box (larynx) would ruin her stage career. As time passed the goitre gradually grew and grew, and she took to wearing the scarves to avoid embarrassment. Blood tests in hospital showed her to have a slightly overactive thyroid gland and three months after treatment with radioactive iodine her blood test came back normal. Equally important, a year later, the size of the goitre had been reduced by at least a half, and she happily abandoned her scarves!

 

Thyroid nodules

Single lumps or nodules in the thyroid are common, and can occur at any age. Women are more likely to be affected than men.

 

A single thyroid nodule

The nodule varies in size from that of a pea to a golf ball or even larger. Like a goitre, the nodule is usually discovered by accident while you’re washing or looking in a mirror. Bleeding into the nodule may cause pain which alerts you to its presence. The discomfort usually lasts two to three days and often, by the time that you have seen a specialist, the nodule will have shrunk or even disappeared.

 

Alternatively, the nodule may be discovered during medical examination for some quite unrelated problem, although neither you nor your family had noticed it before. Most women are aware of the significance of a lump in the breast, and so naturally suspect that a nodule in the thyroid may also mean cancer. This is why your GP will probably want you to see a specialist. In fact, the great majority of single thyroid nodules are not cancers of the thyroid.

 

Confirming the diagnosis

If you have a single thyroid nodule, your blood test will show normal levels of T3, T4 and TSH, which means you’re classified medically as ‘euthyroid’; the exception is the ‘toxic adenoma’ in which the thyroid blood tests will demonstrate an overactive thyroid gland.

 

The thyroid specialist will wish to examine your neck carefully as about half of all patients thought to have a single nodule are in fact found to have generalised nodular enlargement of the thyroid known as multinodular goitre. In this case you can be assured that your condition is not serious.

 

Those people who need further investigations may have an X-ray, ultrasound or radioisotope scan of their thyroid, but the single most important test is fine needle aspiration (FNA) of the lump.

 

The technique is simple, quick and, if necessary, can be carried out two or three times as it doesn’t cause pain or undue discomfort. FNA is one of the most important advances in the care of people with thyroid disease. In the past the majority of those with a single thyroid nodule had to have surgery but many operations can now be avoided simply by examining a small sample of thyroid cells obtained by aspiration in the outpatient clinic. The outcome will be one of those indicated opposite.

 

Benign (non-cancerous) nodules may continue to enlarge over many years and eventually may get so big that an operation is needed to remove them for the sake of your appearance.

 

If you can’t help worrying about the possibility that the lump is harbouring a cancer, your specialist may well suggest operating to remove the nodule so that it can be examined microscopically and resolve the question once and for all.

 

What are the possible outcomes of fine needle aspiration (FNA)?

•    The needle will remove fluid and the nodule will disappear: this means that the nodule must have been a thyroid cyst and no further treatment is needed. Should the cyst recur it can be aspirated once more but, if it comes back yet again, you will need an operation to remove that half of the thyroid containing the cyst.

•    The cells removed from the nodule show that it is a benign lump and therefore you don’t have cancer. Unless the swelling is sufficiently large to be disfiguring, when surgery would be necessary, you can be reassured that no treatment is needed.

•    The cells removed are malignant which means that the nodule is thyroid cancer, and you will need an immediate operation.

•    Sometimes, because of the small number of cells removed, it may be impossible to be certain whether the nodule is benign or malignant (cancer). In this case, you will need an operation to remove the entire nodule so that it can be examined carefully under the microscope.

KEY POINTS

  • In this country, the cause of a goitre usually remains a mystery

  • Young people with a simple diffuse goitre rarely need any treatment

  • You’ll probably be referred to a specialist to have a multinodular goitre investigated, and you may have several tests

  • A small goitre may be left alone, but you’ll have regular blood tests done by your GP as there’s a chance of developing hyperthyroidism later on

  • An operation or treatment with radioactive iodine may be necessary if the goitre is causing problems

  • Thyroxine tablets won’t help to shrink a goitre, although they are still prescribed in some other countries

  • Although people who develop thyroid nodules often worry that the lump may be cancer, this rarely turns out to be the case

  • The simple and painless investigation known as fine needle aspiration means that far fewer people now have to have surgery

  • If you’re concerned about your appearance or can’t stop worrying about the possibility of cancer, you can have an operation to remove the nodule