Endocrine Abstracts

JOINT1266

Background: Diabetes mellitus is primarily classified as Type 1(autoimmune origin, mainly by GAD antibodies), and Type 2 (insulin resistance with B-cell dysfunction); however, a clinically significant subtype, Type 3c diabetes, develops due to chronic pancreatitis, pancreatic surgery, or trauma. While type 3c DM typically results from exocrine damage, the presence of GAD antibodies raises the possibility of distant autoimmune mechanisms contributing to B cell loss. Disguising between T3cDM and autoimmune diabetes is crucial in determining optimal treatment strategies.

Case Report: A previously healthy 22-year-old male with a family history of diabetes and autoimmune disease underwent elective laparoscopic fundoplication for a hiatus hernia, with post-operative complications of severe abdominal pain with steatorrhea, nausea, shortness of breath, insomnia, and fatigue. Pain control due to opioid intolerance (hallucinations on morphine and nausea with oxycodone) required PCA fentanyl 20 mg bolus, paracetamol, and diclofenac supplement. Imaging and laboratory findings confirmed biliary pancreatitis with peri-pancreatic inflammatory changes - Amylase 768U/l (n 25-125U/l) and Lipase 1234U/l(n<150U/l), surgical emphysema, mediastinal gas without pancreatic necrosis. MRCP revealed multiple tiny gallstones and a distal common bile duct calculus. Persistent hyperglycemia ranging from 16-22 mmol/l, HbA1c - 78 (n -7.5%), and autoimmune screening confirmed for GAD antibodies < 200 IU/ml (n <5 IU/ml) and lower C peptide at 0.3mg/ml (n 0.9-4 ng/ml), which raised suspicion of surgical type 3c induced diabetes consistent with exocrine-derived. The patient was managed with basal-bolus insulin (Lantus 28 units nightly, Novorapid 8-14 units per meal) and sliding scale correction for blood glucose 10 mmol/l. The patient was discharged with a management plan of Creon 250,000 units and Humalog 12-20 units with a meal. Tresiba long-acting double strength 84 units at night. The patient claims the symptoms of fatigue, night sweats, diarrhea, and severe unknown origin left upper quadrant radiating to left shoulder abdominal pain.

Conclusion: This is an atypical instance of type 3c diabetes accompanied by post-surgical pancreatitis, biliary blockage, and a rapid onset of GAD-positive diabetes. Acute pancreatitis has been known to elevate GAD-antibody levels, which can result in insulin-dependent diabetes. The presented case is rare as GAD antibody levels are typically lower in autoimmune diabetes (less than 100 U/ML). We suggest that post-surgical pancreatitis caused by gallstones triggered an increase in autoimmune cells, resulting in damage to the islet cells and insulin deficiency. This complex case underscores the necessity of a collaborative approach in both diagnosis and treatment.