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THYROID OVERACTIVE-HYPERTHYROIDISM-THYROTOXICOSIS

What is Thyroid Overactive?

The thyroid gland is found low in the neck and is shaped like a butterfly. It makes chemicals called hormones (thyroxine (T4) and triiodothyronine (T3)) which are released into the blood circulation and distributed to the whole body. The hormones control the speed of all the body's functions (metabolism). In hyperthyroidism (hyper = overactive, thyroidism = thyroid activity) the thyroid gland overproduces these hormones. It often enlarges so that it can be seen as a swelling in the neck. The heart rate increases causing palpitations.

In severe cases or in older people, heart failure may occur. Increased nerve activity causes sweating, diarrhoea, anxiety and trembling of the hands. Excessive production of energy in the body causes weight loss and a feeling of heat, and often stimulates appetite. Loss of protein from muscles causes tiredness and weakness. The same loss of protein from bones may result in thin bones (osteoporosis). In women, periods may become scanty and occasionally stop altogether. Hair may be lost from the scalp. The eyes tend to stare because the nerves in the upper lids are stimulated. The eyes may feel uncomfortable, and double vision may occur. This is called thyroid ophthalmopathy or exophthalmos. Although hyperthyroidism may sometimes produce serious disability, it can always be fully treated. However, prominence of the eyes subsides only very slowly and may remain lifelong.

How does Thyroid Overactive occur?

The common type (Graves' disease - named after the Irish physician who first described it) results from a general overactivity of the thyroid. Other types of hyperthyroidism can occur. For instance, a small part of the thyroid may become overactive (toxic adenoma or nodule). Sometimes, a pre-existing goitre (enlarged thyroid) simply overproduces the thyroid hormone (toxic nodular goitre). Overactivity can occasionally be due to inflammation: subacute thyroiditis. A particular type of hyperthyroidism occasionally occurs about 3 months following childbirth. This so-called post-partum thyroiditis improves by itself, but may be followed by an underactive thyroid.

Why does Thyroid Overactive occur?

The tendency to thyroid problems is often inherited, particularly by female family members. The condition can be triggered by dietary additives or drugs. Iodine (found in cough medicines and a variety of other drugs) may be the culprit in some cases. Once triggered however, cutting back the iodine intake has not been shown to control the thyroid overactivity.

Treatment involved forThyroid Overactive

This will depend on your age and other tests. In particular, a thyroid isotope (nuclear) scan is usually done. This shows whether you have the common diffuse goitre of Graves’ disease, thyroid nodules or the self-limiting form of overactivity called subacute thyroiditis. The three basic treatments are: anti-thyroid drugs (usually carbimazole or propylthiouracil), radioactive iodine, or an operation (thyroidectomy). The decision about the best treatment choice always needs careful discussion. Beta-blockers may be used in the first few weeks; these drugs quieten down the symptoms of the overactive thyroid, by blocking the adrenaline-like effects of thyroid hormones. Propranolol tablets are the most frequently used. Anti-thyroid drugs must always be taken absolutely regularly as prescribed by the doctor. Doses must not be missed. To begin with, many doctors recommend that treatment is split into 3 or 4 doses a day, which speeds up improvement of symptoms in some cases. Treatment can continue for anything from 4 months to several years.

Your doctor may prescribe thyroxine tablets to balance the anti-thyroid drugs. Regular check-ups are essential for tests to check that the doses are correct. Radio-active iodine is a simple and painless form of treatment. You simply take a single drink or capsule of specially treated iodine. It corrects the overactivity by getting rid of overactive thyroid cells. The amount of radioactivity is tiny: no more than one would get from a series of x-rays. Thyroidectomy (removal of most of the thyroid gland) is usually carried out only when the problem recurs after a course of tablet treatment, or if the thyroid gland is particularly large or uncomfortable. It is a safe procedure, but tablet treatment may be needed afterwards if the remaining part of the thyroid remains overactive or becomes underactive. If your thyroid is overactive because of nodules in the thyroid, antithyroid drugs are usually only be a temporary solution, and either radioiodine or surgery are normally recommended.

During treatment for Thyroid Overactive

On anti-thyroid drugs, symptoms will improve quite rapidly. About one patient in fifty will get side-effects in the form of a mild skin rash or joint pains. In rare cases, a very bad sore throat occurs. Any side-effect should be notified to your doctor. Unbalanced doses of these drugs can also make the thyroid activity swing the other way and run too slowly. Let the doctor know if there is any suspicion that this has happened. Some doctors will add thyroxine (T4) to your antithyroid drug to avoid this risk. Radioactive iodine does not cause any immediate problem although the neck may feel a little sore in the first few days. Sometimes, a second dose is needed a few months later. Very often the thyroid will become underactive a few months to a few years after treatment is given. In this case, lifelong treatment with thyroxine tablets will be necessary. Some doctors use an intentionally higher dose and routinely replace with thyroxine tablets to remove any uncertainty. A thyroid blood test is carried out every few weeks initially, and later every year. Any underactivity will show up in the blood test before any symptoms occur. The small amount of radioactivity used has not been shown to cause harm; it cannot cause cancer or leukaemia. Patients should not become pregnant until 4 to 6 months after receiving treatment. Thyroidectomy usually works well, but occasionally the overactivity persists. On other occasions the thyroid becomes underactive (because too much tissue has been removed). It is for this reason that thyroid function is usually checked by a blood test every 12 months for the rest of the patient's life. Prominence and discomfort of the eyes, even if not present at the time of diagnosis, can occasionally occur during or after treatment. This si called ophthalmopathy. The doctor should be informed if the eyes change, particularly if eyesight is affected in any way. Serious deterioration of the eyes may need treatment with drops, with cortisone-like tablet treatment, by radiotherapy, or occasionally even by an operation.

After treatment

Hyperthyroidism can occur again after any treatment, but particularly after a course of anti-thyroid drugs : the risk of relapse is between 50 and 80% over a 10 year period.. Most doctors therefore suggest that a thyroid test should be checked regularly. To reduce the risk of recurrence your doctor may advise you to avoid iodine. This involves avoiding a number of drugs and foods.

If Thyroid Overactive is left Untreated

Symptoms of weakness would develop or worsen. Loss of protein from bone may result in osteoporosis with increased fracture risk : this may not be completely reversible after delayed treatment. Heart failure could develop and may be fatal, particularly in the elderly. Any infection might suddenly worsen the condition, causing high fever and possibly coma (thyroid storm). In rare cases (perhaps 1 in 50) an overactive thyroid condition may settle of its own accord. However, a subsequent relapse is common even in these cases.

Thyroid Overactive during Pregnancy

If you become pregnant while on antithyroid drugs, tell your doctor promptly. The dose is likely to be reduced because pregnancy itself helps to control your thyroid problem. A thyroid blood test will need to be checked every few weeks. Your obstetrician will also take extra care in the later stages of pregnancy, since the baby may be have a tendency to be hyperthyroid. This is rarely a problem, and after birth subsides quickly. Antithyroid drugs are usually continued after childbirth, since a relapse could otherwise be triggered. Breast feeding is safe on the lower doses of antithyroid drugs needed at this time.

Effects on family of Thyroid Overactive

People will notice the difference in the your appearance and even behaviour after treatment. The tendency to a thyroid condition may be inherited. The doctor may therefore suggest that brothers, sisters, parents or children should be tested from time to time. One of them may even have an underactive thyroid (hypothyroidism). A blood test should be done regularly to be sure that the thyroid is functioning correctly.