Particularities of Graves’ Disease in Diabetes Mellitus

Abstract

Graves’ disease and diabetes mellitus (DM) are frequently associated pathologies. The excess of thyroid hormones influences the carbohydrate homeostasis through their action on several organs, leading to alteration of glycemic control and acute hyperglycemic complications in patients with diabetes mellitus. On the other hand, a severe pre-existing metabolic imbalance can mask a life-threatening thyroid crisis, by lowering the thyroid hormones levels, especially triiodothyronine (T3). The prevalence of Graves’ disease is higher in patients with type 1 diabetes mellitus (T1DM). Besides the impact on the glycemic control, Graves’ disease has a high cardiovascular risk, in addition to DM. This is why the thyroid dysfunction screening is so important in patients with DM. These two endocrinopathies may be clinically similar, according to the overlapping signs and symptoms at the start which may cause differential diagnosis problems. Graves’ ophthalmopathy is one of the most specific clinical manifestation of Grave’s disease, being frequently associated with type 2 diabetes mellitus (T2DM). Its severity seems to be closely related to obesity, duration of diabetes, micro and macrovascular complications of diabetes and some types of oral hypoglycemic agents. Oral hypoglycemic agents also influence the thyroid function. Biguanides belong to the most studied therapeutic class. It is very important monitoring the blood glucose until the thyroid function gets normal by antithyroid agents, as well as the thyroid hormones in case of severe glycemic imbalance. Special attention must be paid to the type of treatment we use and its impact on metabolic and hormonal balance.