Nocturnal Hypoglycemia in Aggressively Controlled Diabetes

To the Editor: In the November 12 issue of the Journal Boden et al. described a diabetic patient with permanent brain damage secondary to hypoglycemia who lacked all counterregulatory responses to hypoglycemia.¹ Other investigators had recognized previously² that the normal glucagon response to hypoglycemia was reduced or absent in most patients with Type I diabetes, making them dependent on the catecholamine response as a fail-safe against persistent hypoglycemia. The patient of Boden et al. lacked a catecholamine response to hypoglycemia and was thus defenseless against insulin-induced hypoglycemia. There was no evidence of a defect in hormone production since the responses.