Autoimmune hypoglycemia is characterized by hyperinsulinemia, fasting hypoglycemia, and the presence of insulin auto- antibodies without previous exposure to exogenous insulin. We experienced a case of autoimmune hypoglycemia without diabetes mellitus or any evidence of insulinoma. The insulin auto-antibody and insulin receptor auto-antibody were present. We diagnosed the patient as having autoimmune hypoglycemia and treated with glucocorticoid. After treatment, the hypoglycemic symptoms were resolved. However, four months later, the patient was readmitted with transient diabetic ketoacidosis. After recovery, he showed no signs of diabetes mellitus. We believe that insulin auto-antibodies may play a role in autoimmune hypoglycemia and diabetic ketoacidosis, but its role and mechanism are not precisely known. Further studies are needed to define the action mechanisms and the functions of insulin auto-antibodies: here we present case with a relevant literature.
Diabetic Ketoacidosis/*complications/*immunology/pathology ; Human ; Hypoglycemia/*complications/*immunology/pathology ; Insulin Antibodies/*blood ; Magnetic Resonance Imaging ; Male ; Middle Aged

We describe an unusual case of systemic lupus erythematosus with pulmonary manifestations presenting as hypoglycemia due to anti-insulin receptor antibodies. A 38-year-old female suffered an episode of unconsciousness and was admitted to hospital where her blood glucose was found to be 18 mg/dL. During the hypoglycemic episode, her serum insulin level was inappropriately high (2,207.1 pmol/L; normal range, 18 to 173) and C-peptide level was elevated (1.7 nmol/L; normal range, 0.37 to 1.47). Further blood tests revealed the presence of antinuclear antibodies, anti-double-stranded DNA antibodies, and anti-Ro/SSA, anti-La/SSB, anti-ribonucleoprotein, and anti-insulin receptor antibodies. A computed tomography scan of the abdomen, aimed at tumor localization, such as an insulinoma, instead revealed ground-glass opacities in both lower lungs, and no abnormal finding in the abdomen. For a definitive diagnosis of the lung lesion, video-associated thoracoscopic surgery was performed and histopathological findings showed a pattern of fibrotic non-specific interstitial pneumonia.
Adult ; Autoantibodies/*blood ; *Autoimmunity ; Biological Markers/blood ; Blood Glucose/metabolism ; Female ; Humans ; Hypoglycemia/blood/*complications/immunology ; Insulin/blood ; *Insulin Resistance ; Lung Diseases, Interstitial/diagnosis/*etiology/immunology/surgery ; Lupus Erythematosus, Systemic/*complications/diagnosis/immunology ; Receptor, Insulin/*immunology ; Thoracic Surgery, Video-Assisted ; Tomography, X-Ray Computed ; Treatment Outcome