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THYROID NODULES - GOITRE

What are Thyroid Nodules ?

The thyroid gland is found low in the neck and is usually shaped like a butterfly. When the thyroid is of normal size, it cannot be felt or seen. When it enlarges, it is called a goitre and can then be felt or even seen. Sometimes only a small part enlarges and this is then called a thyroid nodule (lump). Occasionally a number of these nodules develop. This is referred to as a multinodular goitre. The output of a goitre's main hormone, thyroxine, often remains unchanged (normal). Sometimes, however, more thyroid hormone (hyperthyroidism) or less thyroid hormone (hypothyroidism) is produced, thereby causing the symptoms associated with these disorders. In some cases goitres and thyroid lumps may not cause symptoms at all and may be found accidentally. It is normal to worry about the possibility of a cancer, but this is an uncommon cause of thyroid swellings. A goitre can cause pressure on the gullet (difficulty in swallowing) and on the windpipe (difficulty in breathing). Very rarely it affects the voice, causing hoarseness. When it produces these symptoms, the thyroid swelling is sometimes larger and lower in the neck, compressing the gullet and windpipe between the spine and the breastbone. It is then called a retrosternal goitre.

How do Thyroid Nodules occur ?

There are many causes of thyroid swelling. The usual causes are benign (harmless) forms of cell overgrowth or degeneration. The thyroid can also enlarge due to mild inflammation, occasionally produced by viruses (subacute thyroiditis). Cysts and truly benign (non-malignant) tumours are often responsible for a single thyroid lump. Cancerous (malignant) growths do occur, but are uncommon.

Why do Thyroid Nodules occur ?

People may inherit the tendency to goitre from earlier generations. It may also happen at certain times of life (infancy, puberty or pregnancy) when the body needs more thyroid hormone, and the gland is expected to work that much harder. In some people, a goitre appears to be part of the ageing process. Too little dietary iodine causes goitres: this is particularly true in hilly regions where the drinking water contains low levels of iodine (endemic goitre). Too much iodine can also produce a goitre in some susceptible people. Iodine can be found in many different foods and drugs including cough remedies and foods which are artificially coloured red (E127).

Treatment involved for Thyroid Nodules

Blood tests are done to check whether the hormone levels are normal. Usually some type of thyroid scan is performed, to get an idea of the size and shape of the thyroid. Ultrasound scans use sound waves to make a type of radar picture of the gland. Isotope scans use very tiny (and safe) amounts of radioactivity to show which parts of the gland are active. A simple needle suction test of the thyroid (aspiration cytology) allows cells to be examined for any suggestion of cancerous change. It is usually possible to rule out cancer this way, or collapse any cyst which is present. If the goitre is very large, it may need an operation, particularly if there are symptoms from pressure on the neck, or if the goitre is retrosternal. Surgery is also used for smaller nodules which are unsightly, or where there is still any suspicion of cancer. Iodine-containing medicines are rarely used, and in fact can worsen some goitres. Some health foods which contain iodine are often recommended (incorrectly) for people with goitres by health food shops. However, giving thyroid hormones (usually thyroxine) may reduce the size of some goitres. Quite often, no treatment is required at all, and your doctor will either discharge you from follow up, or arrange to review the situation in a few months : he or she make take the opportunity of this visit to repeat a needle suction test.

During treatment for Thyroid Nodules

Hoarseness or difficulty in swallowing or in breathing are important changes to let the doctor know about immediately. Any change in wellbeing may be due to over- or under-function of the thyroid gland. See the doctor about this too so that he or she can do the necessary blood test. Shrinkage of the goitre may occur as a result of taking thyroxine tablets. People often worry that even though a thyroid lump is benign at the start, it might turn malignant. There is no evidence that this ever occurs: once the doctor is sure the swelling is benign from needle suction tests, it will remain that way.

After Treatment

If thyroxine tablets are prescribed, regular checks by your doctor (including blood tests for thyroid activity) are needed. If an operation has been performed, then tests are required from time to time to ensure that thyroxine tablets are not needed to replace inadequate function of the thyroid.

If Thyroid Nodules are left untreated

Often nothing. Goitres occurring for the first time in infancy, puberty and pregnancy usually get smaller by themselves. Other goitres may enlarge quite slowly over a period of time and may then cause pressure symptoms on the throat. Sometimes a small bleed into part of a goitre will cause sudden discomfort and swelling. If this happens, the doctor should be told. Usually these symptoms settle without any treatment. If these episodes recur, it may be a reason to proceed to removal of your thyroid . Cysts sometimes collapse by themselves. Only the very rare malignant (cancerous) nodule is likely to be of concern. Even then, thyroid cancer is one of the less serious types of tumour and is often consistent with a perfectly normal life span, providing it is properly treated. Some goitres or thyroid lumps later become overactive or even underactive. It is therefore important to see a doctor every year or two so that a single thyroid blood test can be done for this purpose.

Effects on family of Thyroid Nodules

Some forms of goitre run in families. Even if there is no goitre in a relative, thyroid function may be disturbed. Since irritability and tiredness are often features of disturbed thyroid function, such symptoms justify a visit to the doctor.