A case of type 1 diabetes with frequent hypoglycemic episodes induced by primary hypothyroidism

A 46-year-old male was admitted due to recurrent hypoglycemic episodes. He developed diabetes mellitus in 2000 and became insulin-dependent in 2006. Following the initiation of insulin treatment, his glycemic control stabilized (HbAlc: 6 % to 7 %). However, in 2013 (at 46 years of age), the frequency of the hypoglycemic episodes increased starting three months prior to hospitalization, which occurred after the patient experienced a low-grade fever for approximately three weeks. Symptoms such as easy fatigability, coldness, hypohidrosis and weight gain were noted concomitantly with the onset of frequent hypoglycemic episodes. He was diagnosed with primary hypothyroidism, and thyroid hormone replacement therapy was started. As a result of switching the patient's insulin therapy from multiple injections to an insulin pump in the hospital, the hypoglycemic episodes became infrequent The patient's frequent hypoglycemic episodes were thought to be induced by primary hypothyroidism due to destructive thyroiditis complicating type 1 diabetes. Thyroid hormone deficiency delays the intestinal absorption of glucose, decreases gluconeogenesis in the liver and impairs glucagon secretion as the counterregulatory response to hypoglycemia Accordingly, hypothyroidism can cause hypoglycemia This case serves as a reminder that hypothyroidism should be taken into consideration as a possible cause of hypoglycemia.