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About Thyroid Conditions

Millions of people around the world have a thyroid disease, such as an enlarged thyroid gland (goiter), non-cancerous or cancerous thyroid nodules, or an overactive thyroid gland. Some thyroid conditions may be treated with medicines, but others are best treated with surgery.

Thyroid-illustration

Definition

The thyroid gland is in the lower part of the front of the neck, just in front of your windpipe. It is shaped like a butterfly, with a “lobe” on each side joined by a thin strip of tissue. The nerves that control your vocal cords are just behind the thyroid.

You cannot usually see or feel the thyroid gland. But if it becomes enlarged, it causes a swelling in the neck called a goiter. Other thyroid conditions may not cause a visible goiter.

The thyroid produces important hormones called thyroxine and T3. These hormones control your metabolism – in other words, how your body gets energy from the foods you eat. If your thyroid is not working well, your body uses energy more slowly or quickly than it should.

If your thyroid is not active enough, it is called hypothyroidism. Hypothyroidism can make you gain weight, feel tired, and struggle with cold temperatures. If your thyroid is too active (hyperthyroidism), you will have more thyroid hormones than your body needs. Hyperthyroidism causes you to lose weight, speeds up your heart rate, and makes you very sensitive to heat.

Causes

A goiter can be caused by several conditions. These include:

  • Grave's disease – in which the thyroid swells and makes too much thyroxine
  • Thyroiditis (inflammation of the thyroid) – which can have several causes, such as a viral infection
  • Iodine deficiency – the thyroid gland needs iodine to make its hormones. If you lack iodine in your diet, the thyroid swells as it tries to make enough hormones
  • Medication – some medicines, such as amiodarone, interferon-alpha, and lithium, can cause a goiter
  • Hereditary factors – some people inherit a tendency for a large thyroid

Thyroid nodules (small lumps in the thyroid) may be caused by:

  • A cyst – a fluid-filled benign (non-cancerous) tumor
  • An adenoma – a solid benign tumor
  • A cancerous tumour (rare)

An overactive thyroid (hyperthyroid) may result from Grave’s disease or thyroid nodules.

The two main causes of an underactive thyroid (hypothyroidism) are autoimmunity (where the thyroid cells are destroyed by white blood cells which attack the thyroid) and as a side effect of treatment for thyroid disease. Other, rare, causes include inherited thyroid deficiency, a complication of viral infection, or a side-effect of certain drugs.

Symptoms

If your thyroid is producing too much hormone, you will likely experience some or all of the symptoms of hyperthyroidism (also called thyrotoxicosis):

  • Being restless, nervous, emotional, irritable, sleeping poorly, and 'always on the go'
  • Shaking hands
  • Losing weight despite increased appetite
  • Palpitations
  • Sweating, a dislike of heat and an increased thirst
  • Diarrhoea or needing to go to the toilet more often than normal
  • Shortness of breath
  • Skin problems such as hair thinning and itching
  • Menstrual changes – often the periods become very light or infrequent
  • Tiredness and muscle weakness
  • A swelling of the thyroid gland in the neck (goiter)

Risk Factors

There are some factors that can increase your risk of developing a thyroid disorder. Some of these are:

  • Gender – women are 6 to 8 times more likely than men to develop a thyroid condition
  • Age – people aged over 50 years have increased risk of thyroid disease
  • A history of thyroid disorders in your family or yourself – for example, if you had thyroid problems during or after pregnancy, or if people in your close family have had thyroid conditions, your risk of thyroid disease is increased
  • Cigarette smoking – if you are, or were a smoker, you have an increased risk of developing autoimmune thyroid disease
  • Iodine intake – if you do not have enough iodine in your diet or, conversely, if you use iodine or herbal supplements, you may increase the risk of thyroid problems
  • Certain medical treatments and drugs increase the risk of developing thyroid problems
  • Major stress – significant life events like death or divorce, or major physical stress like a car accident, may trigger autoimmune thyroid disease

Diagnosis

To diagnose a thyroid problem, your doctor will need to examine you. Your doctor will pay special attention to your thyroid gland and other areas of your body where thyroid problems may be reflected, such as your skin, nails, hair, heart, weight, and body temperature. In addition, blood tests will be performed to measure the levels of thyroid hormones. You may also need to have thyroid imaging tests so your doctor can “see” your thyroid. Lastly, if you have a lump on your thyroid, a thin needle may be inserted directly into the lump to remove some cells that will be checked for cancer.

Information on this site should not be used as a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.

Last updated: 29 Mar 2011

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