Abstract
PURPOSE: To present a case of ulcerative colitis associated with teprotumumab treatment for thyroid eye disease. OBSERVATIONS: A 46-year-old Indian female was treated with teprotumumab (Tepezza) for severe thyroid eye disease within 9 months of diagnosis. The patient noted progression of her disease on oral prednisone and demonstrated severe, debilitating proptosis accompanied by eye ache and dry eyes. After 5 infusions of teprotumumab over a four-month period, the patient developed bloody diarrhea and fecal urgency. These symptoms progressively worsened and after two additional treatments, she underwent a colonoscopy. This confirmed the diagnosis of ulcerative colitis (UC). Treatment with teprotumumab was halted prior to the administration of the 8th infusion; however, the patient continued to have severe gastrointestinal symptoms two months after her last treatment. CONCLUSIONS AND IMPORTANCE: Teprotumumab is an insulin-like growth factor-1 receptor (IGF-1R) inhibitor demonstrated to improve proptosis in patients with active thyroid eye disease. Most adverse events reported are mild or moderate in severity; however, inflammatory bowel disease (IBD) is a serious adverse event that can develop as a result of treatment.