Disease of the month: Thyroid disease

Fergus Bescoby looks at the insurance implications of this condition which is particularly common in women

The thyroid is a butterfly-shaped, brownish red gland located in the front of the neck just below the Adam’s apple. It usually weighs less than an ounce (28gm).
But as small as it is, the thyroid has an enormously important job to do, especially for teenagers. It manufactures the hormones that help control metabolism and growth.

To do its job, the thyroid needs a chemical element called iodine that the body absorbs from the foods we eat, such as seafood and salt, as well as the water we drink.

The entire body contains about 50 milligrams of iodine. About a fifth to a third of that supply (ten to 15mgs) is stored in the thyroid. The thyroid combines the iodine with tyrosine (an essential amino acid) to make important hormones. These are thyroxine (T4) and triiodothyronine (T3), representing 99.9% and 0.1% of thyroid hormones respectively.

Thyroid hormones are released from the gland and travel to the body’s cells through the bloodstream. They help control the growth and the structure of bones, sexual development (puberty) and many other body functions.
By helping the cells convert oxygen and calories into the energy they need to work properly, these hormones are important in determining if the body will mature as it should.

Thyroid hormones also directly affect how most of the organs function. So if the thyroid is not operating properly, it can cause problems in lots of other parts of the body.

The thyroid may become overactive (hyperthyroidism) or underactive (hypothyroidism). If the body is producing too much hormone, and the gland is overactive, you are said to be hyperthyroid. This affects 2% of women and 0.2% of men. If, however the body is not producing enough hormone, and the gland is underactive, you are said to be hypothyroid, which affects 2% of women and 0.1% of men.

Hyperthyroidism

The clinical names for an overactive thyroid gland are hyperthyroidism (excess of thyroid) and thyrotoxicosis (poisoning by the thyroid). The main causes of this condition include:

■ Graves’ Disease – an autoimmune disease where antibodies stimulate the thyroid cells to secrete excess thyroid hormone. This is the most common cause of an overactive thyroid (80%) and can result in Grave’s Ophthalmopathy
■ Toxic multinodular goitre (Plummer’s disease) – this is an enlarged thyroid gland with lumps on it that have become overactive