Myxoedema followed by TSAb-induced hyperthyroidism: report of 2 cases

The development of spontaneous hyperthyroidism following primary hypothyroidism is an unusual occurrence. We report two cases of confirmed primary hypothyroidism who subsequently became hyperthyroid. Thyroid stimulating antibodies were present in the sera of both patients during the hyperthyroid state. The significance of this sequence of events is discussed and a possible explanation proposed.