Primary hypothyroidism followed by hyperthyroidism. Five case reports

Five patients are described, who developed primary hypothyroidism between 25 and 57 years of age. They were all adequately treated with L-thyroxine. Graves' disease developed six months to 34 years later. Two had TSH binding inhibiting immunoglobulin (TBII) in their serum at this stage. All were treated with carbimazole, and 3 have experienced relapse upon withdrawal. Our patients are discussed in relation to the 16 cases previously reported. The pathogenesis of this condition is open to speculation.