Secondary diabetes is a condition of hyperglycemia which develops after the destruction of the pancreatic tissue by an acquired disease with subsequent impairment of exocrine and endocrine pancreatic functions. In general, any pathologic process of the pancreatic acinar tissue may results in an insult to its endocrine component, leading to some degree of hormone insufficiency. This condition was first described in 1788 by Sir Thomas Cawley, but it was soon appreciated that hyperglycemia can ensues acute and chronic pancreatitis, partial and total pancreatectomy, neoplasia as well as systemic processes involving the pancreas, such as hemochromatosis and cystic fibrosis. The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association has identified these forms of diabetes as “diabetes secondary to diseases of the exocrine pancreas.” The new diagnostic criteria for diabetes introduced by the ADA and WHO Expert Committees are likely to influence the prevalence of diabetes in patients with diseases of the exocrine pancreas, but direct assessment using the new criteria is still too scanty. When the 1979 NDDG and 1985 WHO criteria are used, it can be calculated that diabetes secondary to disease of the exocrine pancreas represents, approximately, 0.5% of all cases of diabetes mellitus. Its frequency is likely to be twice as high in populations with heavy alcohol consumption. In the tropics, the prevalence of diabetes secondary to fibrocalculous pancreatitis can be as high as 10–20%. At variance with the selective B‐cell destruction occurring in type 1 diabetes, pancreatic diabetes is characterized by concomitant destruction of all endocrine cells of the islet of Langherans. The dual insulin–glucagon deficit is responsible for many of the metabolic and clinical manifestation of this form of diabetes, including lower risk for ketoacidosis and more frequent and severe hypoglycemic episodes. Since the late 1950s, the general idea has been that secondary diabetes was not associated with vascular complications. However, with the improved life expectancy of these patients during the past few years, a similar prevalence of retinopathy and microalbuminuria has been described in pancreatic and type 1 diabetes mellitus. The knowledge of the hormonal, metabolic, and clinical features of these forms of diabetes is essential in defining the most appropriate therapeutic strategies.
