Autoantibodies to the insulin receptor as a cause of autoimmune hypoglycemia in systemic lupus erythematosus.

A 52-year-old black woman presented with clinical features of systemic lupus erythematosus (SLE) and severe fasting hypoglycemia. Hypoglycemia was secondary to autoantibodies to the insulin receptor that were detected in the patient's serum. There were no anti-insulin antibodies, and other causes of hypoglycemia were excluded. Treatment with high-dose glucocorticoids resulted in restoration of euglycemia associated with resolution of circulating anti-receptor antibodies and parallel improvement in clinical and laboratory features of SLE. This case is compared with other cases of autoimmune hypoglycemia due to anti-receptor antibodies.