[Secondary diabetes in chronic pancreatitis]

Abstract

In the majority of patients suffering from chronic pancreatitis an endocrine pancreatic insufficiency is correlated with exocrine dysfunction. The prevalence of impaired or diabetic glucose tolerance is 40-70%, half of these patients suffer from an insulin-dependent diabetes mellitus. In general the probability of endocrine insufficiency progressively increases within the ten years following diagnosis of chronic pancreatitis. Onset and severity of the endocrine dysfunction depend on parenchymal destruction of the pancreas but are also influenced by ongoing alcohol consumption. Pathological findings in the endocrine pancreas are a loss of B-cells with decrease in secretion of insulin but also a loss of B-cell responsiveness to glucose by impaired perisinusoidal diffusion. Disturbances of the enteroinsulinar axis with diminished levels of incretins due to an exocrine insufficiency are also discussed. In addition, an impaired A-cell function may be important, that is characterized by diminished levels of stimulated glucagon. Increased plasma levels of somatostatin were found, the source of which is unknown. The susceptibility to severe hypoglycemia in patients with diabetes mellitus secondary to chronic pancreatitis is higher than in Type I diabetics. This is mainly caused by the impaired glucagon secretion but also influenced by malnutrition and concomitant hepatic dysfunction due to the toxic affect of alcohol. Diagnostic procedures are the measurement of C-peptide-concentrations and profiles of blood glucose after fasting and stimulation with L-arginine or glucose. Especially in the beginning of the endocrine insufficiency the determination of basal levels of blood glucose or C-peptide are not useful. Unless treatment by diet is effective, the therapy of diabetes secondary to chronic pancreatitis should be done by insulin replacement. A certain degree of hyperglycemia may be tolerated due to the risk of hypoglycemia and the persistent alcohol consumption in these patients. Intensified insulin therapy should only be done in selected patients with good compliance. Long-term complications in patients with pancreatogenic diabetes are comparable to diabetes Type I and largely depend on the duration of the diabetes. Life expectancy is reduced, death in these patients is mainly due to persistent alcohol and nicotine abuse (cardiovascular disease, malignant tumors, etc.), in only a minority pancreatitis or diabetes (mainly hypoglycaemia) are relevant risk factors.