thyrotoxicosis symptoms and signshypothyroidism and hyperthyroidismmethimazole for hyperthyroidismsubclinical thyrotoxicosisamiodarone thyrotoxicosissubclinical hyperthyroidism treatmentthyrotoxicosis managementautoimmune thyrotoxicosisiatrogenic thyrotoxicosisautoimmune hyperthyroidismamiodarone hyperthyroidismthyrotoxicosis diagnosis