Endocrine Abstracts

Introduction: Brittle hypertyroidism is a term used for the clinical situation characterized by hypo-hyperthyroidism with antithyroid drugs, despite good compliance and follow-up. Here, we presented five patients suggested to have Brittle Graves.

Case-1: Thyrotoxicosis was observed in a 57-year-old female patient and Graves was diagnosed after laboratory and imaging examinations 25 months after initiation of propylthiouracil 50 mg/day, she developed hypothyroidism and the drug was discontinued. Thyrotoxicosis recurred in 3 months and the patient underwent thyroidectomy. The histopathological diagnosis was lymphocytic thyroiditis.

Case-2: Graves was diagnosed in a 22-year-old female patient with Down syndrome. After 15 days of propylthiouracil treatment, serum TSH was 100 IU/ml and hyper-hypothyroid periods recurred despite appropriate treatment and thyroidectomy was offered.

Case-3: Thyrotoxicosis was observed in a 48-year-old female patient with a history of levothyroxine use for 10 years. She had positive TSH receptor antibody and ophthalmopathy. Methimazole was started because thyrotoxic state persisted despite discontinuation of levothyroxine, but hypothyroidism developed in a short time and thyroidectomy was offered.

Case-4: A 67-year-old male patient with a diagnosis of Graves disease has used methimazol for 14 months and the drug was discontinued due to hypothyroidism. Recurrent periods of hyper-hypothyroidism developed in follow-up and BTT (bilateral total thyroidectomy) was performed.

Conclusion: Hyper-hypothyroid fluctuations can be observed in patients with Graves disease. This clinical manifestation overlap with hashitoxicosis. “Brittle Graves” seems to be a better definition for such cases.