Rapid improvement of severe fatty liver in a case of fulminant type 1 diabetes following insulin treatment.

A 36-year-old woman presented to the emergency room with a consciousness disorder after developing abdominal pain with diarrhea for 2 days. She presented with marked hyperglycemia, ketoacidosis, and increased serum free fatty acid (FFA) levels; however, no elevation in the glycated hemoglobin (HbA1c) levels was observed. Based on the marked depletion of insulin secretion, the patient was diagnosed as diabetic ketoacidosis attributed to fulminant type 1 diabetes (FT1D). Computed tomography on admission revealed severe fatty liver (FL), which improved 17 h following insulin treatment. Insulin treatment also suppressed the serum FFA levels. Some cases of FT1D with FL and liver dysfunction have been reported previously; however, its pathogenesis and clinical course remain unclear. Compared to previous reports, this case reported the shortest time for FL improvement. In this case, rapid and severe insulin deficiency led to a markedly high FFA level and significant accumulation of triglycerides in the hepatocytes, resulting in severe FL. A rapid and large dose of insulin was administered when systemic insulin sensitivity was nearly maximal owing to insulin deficiency, increased insulin efficacy, early reduction of FFA, suppressed triglyceride accumulation in the hepatocytes, and increased triglyceride excretion from the liver. All these factors could have contributed to the rapid improvement in FL.