Resistance to Thyroid Hormone in a Boy with a Severe, Complex, Congenital Heart Defect (CHD) Requiring Multiple Cardiac Surgeries-Whether and How to Prepare Child for the Surgery.

Background: Resistance to thyroid hormones (RTH) is a rare, genetically determined disease characterised by reduced tissue sensitivity to thyroid hormones (THs). It is caused by mutations in genes encoding the receptors for thyroid hormones, α (THRα) or β (THRβ), the distribution of which varies between tissues. Therefore, patients present with elevated TH levels with unsuppressed TSH levels, and symptoms of both hypothyroidism and hyperthyroidism may be present. Methods: Hence, we report the case of a boy with a complex, cyanotic, congenital heart defect who was also diagnosed with TH resistance syndrome. Results: Because of the clinical features of hyperthyroidism in preparation for cardiac surgery, thiamazole was administered, resulting in the normalisation of TH effects on the α-receptor for HTs. Due to the effectiveness of the proposed treatment, it was further introduced before the further stages of cardiac surgeries. Conclusions: The management of RTH is a constant challenge for clinicians and must be individualised.