Abstract
An association between diabetes mellitus and ulcerative colitis (UC) has been suggested in epidemiological studies. However, the etiology of the coexistence of these diseases is unknown. Here, we report a case of diabetes mellitus due to insufficient insulin secretion newly developed through exacerbation of UC. A 66-year-old woman without a history of diabetes or obesity who was diagnosed with UC and started taking mesalazine four years previously presented with abdominal pain and mucous stool that began a month previously. She was treated with an increased dose of mesalazine without steroid, but started presenting excessive thirst and weight loss. A blood test showed highly elevated glucose and HbA1c levels (639 mg/dl and 10.0 %, respectively), indicating newly onset diabetes. Although islet-specific autoantibodies were undetectable and serum ketones were not significantly increased, her fasting serum CPR level was as low as 0.48 ng/ml even after the glucose level improved, indicating that insulin therapy was continuously required. When the UC conditions were improved four months later, the fasting CPR level was increased to 1.45 ng/ml. She successfully discontinued insulin therapy seven months later. In this case, we found a relation between UC activity and the ability to secrete insulin. Hospitalists should be cognizant of diabetes in patients with uncontrolled UC.
