LAUSR

Hashimoto's thyroiditis is one of the most common organspecific autoimune diseases and the most frequent cause of hypothyroidism in areas with sufficient iodine supply. Excessively stimulated T cells CD4+ and their differentiated cells are known to play a key role in the pathogenesis. It is currently accepted that on the one hand genetic susceptibility, environmental factors, existential factors (gender difference) play an important role, on the other hand gut and intestinal microbiota seem to contribute to its development too. Diagnosis requires a detailed medical history, sonography, and blood analysis of thyroid function and thyroid antibodies. In case of an overt or subclinical hypothyroidism long-term or lifelong levothyroxine replacement may be needed, with a special focus on phases with an additional demand like during pregnancy. There are multifactorial reasons for poor response to therapy despite normal TSH levels in blood sampling like co-morbidities (other organspecific autoimmune diseases, psychiatric diseases), lack of vitamin and trace elements. Pharmacogenomic and pharmacokinetic factors may impact on levothyroxine bioavailability, also thyroid hormone resistance and transport- or conversion disorder due to insulin resistance or adrenal insufficiency for example. The relations between thyroid function, mental status and psychiatric disorders seem to be complex and the mechanisms underlying the interactions remain to be clarified. Continuing research in biochemical, genetic and neuroimaging fields are needed.