Diagnosis and treatment of thyroid disorders in obese patients — what do we know?

Obesity-related changes in the composition of the body interfere with the proper functioning of the thyrotropic axis, leading to its disturbances and changes in the structure of the thyroid gland. Distinguishing what is related to obesity and what constitutes pathological changes is crucial for the proper treatment of patients. In this paper authors present a case of a patient with a diet-induced obesity, whose only abnormalities in thyroid assessment included an elevated level of thyroid stimulating hormone (TSH) and hypoechoic thyroid gland on ultrasound. Based on this clinical situation, we reviewed literature in order to establish rules regarding management of thyroid disorders in obese individuals. The most common obesity-related thyroid abnormality is an isolated increase of TSH, without clinical symptoms of hypothyroidism, defined as hyperthyrotropinaemia. In obese adults, autoimmune thyroid disease is found equally often as in the normal-weight population. Thyroid enlargement, increased risk of nodules, and decreased echogenicity, not related to autoimmunity, is frequent among obese individuals. Weight loss leads to the normalisation of TSH levels and thyroid echogenicity. Excessive weight can influence both the TSH level and ultrasound image of the thyroid gland; however, these findings can be reversed by weight reduction. Therefore, in asymptomatic obese patients elevated TSH should not be treated with thyroid hormone replacement.