How to recognise an overactive thyroid
As is the case with an underactive thyroid, the indications tend to be of a general nature and therefore an overactive thyroid often isn't immediately recognised. "The TSH in the blood is a super screening value that can be easily determined by a family doctor," says Hans Steinert, Managing Director of the Thyroid Centre at Hirslanden Klinik Zurich.
Low TSH value
In the case of an overactive thyroid, even if it's only latent and the number of hormones in the body is therefore still within the normal range, the TSH value is low. This indicates that the thyroid gland is producing too many hormones and the TSH hormone (Thyroid Stimulating Hormone) is signalling the thyroid gland to stop producing.
What happens to the body with an overactive thyroid?
When the thyroid gland is overactive, it produces too many hormones and raises the patient’s metabolism to such an extent that the body reacts with symptoms like diarrhoea, a rapid pulse rate or a racing heart. The most common causes of an overactive thyroid are Graves' disease and thyroid autonomy.
Graves' disease is a typical thyroid disease in which the opposite of Hashimoto's actually happens: the autoimmune disease causes the thyroid gland to keep producing hormones even though there would have been enough long ago. In Graves' disease, antibodies form against the receptors that are responsible for the absorption of thyroid hormones. These antibodies typically also form deposits behind the eyes, which can lead to watery eyes, visual disturbances or even protruding eyes.
Thyroid autonomy tends to occur in older people over 60 and is particularly difficult to diagnose because it is often latent. This means that the thyroid values are still within the norm and only the TSH is low. "Patients are then somewhat tired, forgetful or rather weak," Steinert says. They often make the mistake of attributing this to their ageing body and don't think of a thyroid disorder.
Treatment and dealing with the condition
There are medicines – called thyrostatic drugs – that can treat an overactive thyroid in Graves' disease. These drugs prevent further thyroid hormones from being produced or secreted. However, they only help about half of the patients. If these drugs don't achieve the desired result, the next step is to remove the thyroid gland by surgery or to treat it with radioiodine therapy. Daily hormone replacement supplements then give the body the substances it needs.
The hot nodules in thyroid autonomy cannot be cured with medication. Surgery on the thyroid gland, radioiodine therapy or, more recently, thermoablation are required. The nodules are removed by radio waves and the resulting heat.