A Novel Case of Hyperglycemic Hyperosmolar State After the Use of Teprotumumab in a Patient With Thyroid Eye Disease

BACKGROUND/OBJECTIVE: Teprotumumab, a novel treatment for thyroid eye disease (TED), which blocks the insulin-like growth factor 1 receptor, has been associated with improvement in proptosis and inflammatory ocular symptoms. In the original trials, hyperglycemia was reported in 5% to 12% of patients; however, none required hospitalization. We report a case of hyperglycemic hyperosmolar state after the first infusion of teprotumumab. CASE REPORT: A 56-year-old woman with Graves’ disease, severe thyroid eye disease, and prediabetes presented with polyuria, polydipsia, nausea, abdominal pain, headache, dizziness, and a fall to the emergency department 3 weeks after her first teprotumumab infusion. She was noted to have serum glucose levels of 939 mg/dL, serum bicarbonate levels of 28 meq/dL, serum osmolality of 324 mOsm/kg, and trace ketones in urine. She was treated with intravenous fluids and insulin with subsequent improvement in clinical status and biochemical profile. She was then discharged on multiple daily injections of insulin. DISCUSSION: Hyperglycemia is a known adverse effect of insulin-like growth factor 1 receptor inhibitors like teprotumumab. The incidence of hyperglycemia in the original trials was 5% to 12%. Most cases were mild and resolved with titration of current diabetes medications. No cases of hospitalization due to severe hyperglycemia or hyperglycemic hyperosmolar state have been reported until now. CONCLUSION: We intend to highlight the severity of hyperglycemia that could occur with the use of teprotumumab and the need for research to evaluate the true incidence of this condition.