Thyroid diseases are quite common in Australia, affecting about 850,000 people (or 7.5 per cent of women and 1.5 per cent of men). Fortunately, thyroid conditions are not usually life threatening and respond well to treatment.

The thyroid gland is a soft, butterfly shaped gland that lies wrapped around the windpipe below the Adam's Apple. Its job is to secrete thyroid hormones that help regulate metabolism – in other words, the many chemical processes that keep our bodies ticking over.

When the gland is healthy, it releases as much thyroid hormone as we need to keep our metabolism on an even keel. It knows just how much to release because of the feedback mechanisms between a gland in the base of the brain, called the pituitary, and a small part of the brain above the pituitary, called the hypothalamus.

Hyperthyroidism (or thyrotoxicosis) is where the thyroid gland becomes overactive. Common symptoms include fatigue, weight loss, palpitations, tremor and diarrhoea.

Hypothyroidism is where the thyroid is underactive. Common symptoms include fatigue, weight gain, feeling the cold, constipation and dry skin.

Thyroid nodules are very common and mostly not a cause for concern. The major issue is determining which nodules require a biopsy to ensure they are not a cancer. Ultrasound is an essential part of determining this.

Goitre simply means enlarged thyroid and can be caused by many different things including iodine deficiency, multiple nodules, and hyperthyroidism. The thyroid may enlarge to the point where surgical removal is required. Radioactive iodine treatment may also help shrink the gland in some circumstances.

For more information on thyroid disorders go to:
http://www.abc.net.au/health/library/stories/2005/06/16/1831822.htm