Abstract Introduction IgG4-related disease (IgG4-RD) AIP type 1 is a chronic fibro-inflammatory disorder affecting the pancreas and biliary system. While corticosteroids remain the mainstay of treatment, prolonged use may lead to complications including pancreatic insufficiency and secondary diabetes mellitus. Clinical Case A 62-year-old male presented in 2021 with obstructive jaundice. Imaging showed a distal biliary stricture, and ERCP with stenting was performed. Elevated serum IgG4 levels (3× upper limit of normal) and biopsy confirmed IgG4-RD with pancreatobiliary involvement. He responded to corticosteroids but experienced multiple relapses, necessitating repeated courses. He declined steroid-sparing agents. The patient developed new-onset diabetes during treatment, with HbA1c values ranging from 7.0% to 9.2%, and GMI of 8.7%. Notably, his glycemic control improved following the initiation of steroids but worsened upon tapering, with HbA1c rising to 8.5%. After steroid therapy was reinstated, his HbA1c decreased again to 6.9%. He was managed with insulin glargine and lispro and monitored with Freestyle Libre 2. Concurrent pancreatic exocrine insufficiency was confirmed (low fecal elastase), and pancreatic enzyme replacement therapy (PERT) was started. This case illustrates the metabolic impact of chronic corticosteroid use in IgG4-RD, particularly the development of type 3c diabetes mellitus (T3cDM). Studies suggest diabetes improves in 50–60% of AIP patients if treated early; however, repeated steroid exposure and pancreatic atrophy may lead to permanent dysfunction. Multidisciplinary management is essential. Conclusion Early detection and individualized therapy in IgG4-RD are key to reducing endocrine and exocrine complications. Recognizing T3cDM as a potential consequence enables timely intervention and improved outcomes.
Nasir et al. (Thu,) studied this question.