Berlin – An overactive thyroid increases the risk of stroke or cardiac arrest. Dementia is also possible. According to current studies, people with slightly elevated hormone levels are already at risk. The Professional Association of German nuclear medicine (BDN) advises people with a thyroid enlargement therefore a hormone check.
The risks of a thyroid gland over-function for heart and circulation are known, says the BDN chairman Detlef Moka. He therefore urges all concerned to receive treatment. When exactly an overfunction of the thyroid is present is, however, under expert controversy.abstract-1293337_1280The concentration of the thyroidoid stimulating hormone (TSH) is considered to be a measure of the degree. It is formed by the pituitary gland and increases the production of the hormone T4 in the thyroid gland. There is a negative feedback between both hormones: an increase of T4 slows the release of TSH. A low TSH therefore indicates an overactive thyroid. To date, TSH values up to 4.0 mU / l have been considered safe in adults. However, new findings from the Netherlands make it doubtful.

Layal Chaker from the Erasmus University in Rotterdam has evaluated the data of 10,318 inhabitants, which are regularly observed within the Rotterdam Study. In the first nine years, 261 participants died of sudden cardiac death, which is usually a consequence of cardiac arrhythmia. “Among them were strikingly many people with slightly low TSH values,” explained Moka. “These people still have no symptoms of over-function, even the T4 values are still in the normal range. We therefore speak of a latent over-function. ”
According to the results, the Chaker in the journal Circulation published, people with latent hyperthyroidism have an increased by a factor of 2.5 to risk of sudden cardiac death. “The risk of sudden cardiac death within ten years was no less than four percent,” Moka says. In another study in the Journal of Clinical Endocrinology & Metabolism reported Chaker, that the risk of stroke is increased, and a few days ago announced the researcher in Neurology with that people often fall ill with latent hyperthyroidism aged with dementia.

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TSH targets redefine
Although the study can not prove that treatment reduces the risk of the person concerned, the results for BDN expert Moka two reasons are worrying. “On the one hand, we must consider how people with latent hyperfunction of the thyroid can be better protected,” says the nuclear medicine expert. “A comprehensive study is now urgently needed to examine the value of treatment.” Conclusions are likely to be for people who are treated with thyroid hormones because of an underactive function. “Most physicians are seeking a TSH value that corresponds to a latent overfunction. This can no longer be advised, “says Moka.

Functional tests of the thyroid gland are an important area of application for nuclear medicine. With the scintigraphy, they can clarify whether nodes in the thyroid gland are responsible for an overfunction. The treatment can then be carried out with radioactively labeled iodine, which accumulates in the thyroid gland and suppresses hormone formation in the long term.

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