What is the thyroid gland?
The thyroid gland is a small organ located at the level of the larynx. With its two lobes to the left and right of the trachea, it looks like a butterfly. The two lobes are connected in the middle by a small bridge, the isthmus.
What is the thyroid gland’s function?
The thyroid gland functions like a power station in our body. It produces two hormones: tetraiodothyronine (T4) and triiodothyronine (T3). These regulate our metabolism and are therefore of great importance to our body.
We need them:
Among other things, they ensure that we don't store too many carbohydrates or use too much energy. In brief, we cannot live without these thyroid hormones.
Our brain uses another hormone, TSH (thyroid stimulating hormone) to regulate the production of thyroid hormones. Hans Steinert, nuclear medicine specialist and managing director of the Thyroid Centre at Klinik Hirslanden in Zurich, says: «TSH is the hormone controlling the thyroid gland. It indicates whether the thyroid gland is producing too many or too few hormones. Production levels are then either curbed or stimulated accordingly.» The TSH level is a good indicator to use in a diagnosis when the first symptoms of a disorder appear but thyroid levels themselves are still normal.
How iodine supply affects the thyroid
As the names of the two hormones suggest, thyroid hormones are dependent on iodine supply. T4 contains four iodine molecules and T3 contains three iodine molecules. We need to consume iodine through our food for the thyroid gland to produce these hormones. In areas of iodine deficiency, the thyroid gland begins to compensate for the deficiency by growing in size. This excess growth can – after decades – lead to goitre. Autonomous nodules can also form.
Thyroid gland disorders
There are various conditions that are triggered by a thyroid gland disorder. The term for when the thyroid gland produces too many hormones is hyperthyroidism; if it produces too few, the condition is called hypothyroidism.
Any nodules appearing in the thyroid gland can be benign or malignant. The medical term for the latter is carcinoma or thyroid cancer. With carcinoma, the patient has a non-functional «cold nodule». «Hot nodules» is the term used to describe nodules that produce an enormous amount of thyroid hormones. This leads to hyperthyroidism. The remaining, healthy thyroid gland then leaves hormone production to the hot nodules.
Women are more affected
Women are significantly more affected by all thyroid disorders than men. «The exact cause has yet to be fully researched. However, there is much evidence to suggest that hormonal changes in the female body are a possible link,» says Steinert.
The treatment depends on the disease or disorder. Today, if surgery is necessary, a lobe – i.e. one side of the thyroid gland – is completely removed. This is because the risk increases many times over with every new operation.
Treatment for hot nodules
In the case of a hot nodule, the affected lobe is therefore completely removed. Other treatment options exist: radioiodine therapy and, more recently, thermoablation. In radioiodine therapy, radioactive rays are directed at the hot nodules to destroy them. In thermoablation, the nodules are eliminated by radio waves and the resulting heat.
Treatment for carcinoma
In the case of carcinoma, one lobe is always surgically removed and, in some circumstances, both lobes are removed. After the operation, radioiodine therapy may be required to eradicate offshoots, for example, or to prevent recurrence.