Thyroid function is related to the welfare state beyond what is treated routinely. The timely and accurate diagnosis of thyroid diseases faces some particular circumstances, for example, in cases of hyperthyroidism in pregnancy due to masking of symptoms; and in the case of hypothyroidism, although the treatment is universal with levothyroxine, regardless of the cause, the challenge is to know when the cause is autoimmune, who in the same family have the genes to develop the disease and even less knowledge can be found when trying to understand why a whole spectrum of thyroid diseases can occur in the same family. On the other hand, it seems that there is a clinical inertia in seeing hypothyroidism as predisposing to develop obesity, without taking into account that thyroid failure may rather be a consequence of morbid obesity. Finally, making an approach to genomic medicine is an obligation at the time of the study of thyroid disease.
The objective is to encourage a more thorough investigation of the thyroid profile as a cause or consequence of a disease. Thus, this special issue is intended to provide information to understand the implications of altered functioning in clinical settings such as critical conditions, morbid obesity, drug use, pregnancy, old age, cancer, etc.