Hypoglycemic disorders in adults

The diagnosis of hypoglycemia in adults depends on fulfilling Whipple’s triad—symptoms are compatible with hypoglycemia, occur in the presence of low venous glucose, and are reversed by correction of the low circulating glucose. Typically these disorders have very different etiologies depending upon the context within which they occur. Of course, overall, the most likely cause of hypoglycemia is because of inadvertent or intentional misuse of glucose-lowering agents, such as insulin and sulfonylureas, in adults with and without type 2 diabetes. Once these obvious causes are excluded, hypoglycemia in the hospitalized patient is likely due to medication or the interaction of disease with medication. On the other hand, a healthy patient with no history of upper gastrointestinal surgery is most likely to have an insulinoma as the underlying cause of hypoglycemia. Other possible causes of hypoglycemia in adults include postbariatric surgery, noninsulinoma pancreatogenous hypoglycemia syndrome, autoimmune hypoglycemia syndrome, and, rarely, nonislet cell tumors, including mesenchymal, epithelial, hematopoietic, and rarely a paraneoplastic manifestation of other neuroendocrine tumors. In this chapter, we provide an overview of the management of hypoglycemic disorders in adults.