Assessment of Clinical and Laboratory Limits between Hashitoxicosis and Graves’ Disease

BACKGROUND: Determine the clinical and laboratory features of Hashitoxicosis (Htx) and set standards that will help perform a differential diagnosis with Graves’Disease (GD). SUBJECTS & METHODS: we evaluated 45 patients with Htx (Hashi-group) diagnosed between January/1995 and July/2019 with autoimmune hyperthyroidism and cytology compatible with Hashimoto’s Thyroiditis (HT). The control group consisted of 51 patients with GD (Graves-group). RESULTS: clinical hyperthyroidism, free T4 (FT4), thyroid volume and need for antithyroid drugs were higher in the Graves-Group. Values of anti-thyroid antibodies and TSH were higher in the Hashi-Group. The definitive diagnostic criterion was cytology. Regarding the clinical course, 95% of the Hashi-Group had hyperthyroidism of short duration, while 84.3% of Graves-Group required radioactive iodine (RAI). CONCLUSION: hyperthyroidism due to HT was milder than that associated with GD. In most citology was able to distinguish HT from GD and predict spontaneous resolution preventing unnecessary RAI.