The hypoglycemic syndrome (insulinoma): pathogenesis, etiology, laboratory diagnosis (review, part 1)

Hypoglycemic syndrome is a cluster of symptoms developing due to imbalance in the glucose homeostasis system leading to hypoglycemia and that is corrected by glucose administration. A rapid and significant drop of glucose blood level may lead to life-threatening condition, hypoglycemic coma. Chronic hypoglycemia leads to irreversible changes in the central nervous system, while forced frequent meals with high carbohydrate content in order to correct hypoglycemia significantly increases body weight, until morbid obesity develops. Hence, the hypoglycemic syndrome is a topical problem of contemporary medicine. Insulinoma is the most common cause of pancreatogenous hypoglycemia in patients without diabetes mellitus. Exogenous administration of hypoglycemic agents, severe multiple organ and tumor pathologies, sequelae of bariatric surgery, deficiency of contrainsular hormones, genetically determined enzyme disorders and autoimmune diseases may also cause the hypoglycemic syndrome. The primary diagnostic tasks determining the choice of the treatment approach involve confirming the hypoglycemic syndrome and determining its etiology. The test after 3-day-long fasting and other tests are used for this purpose. In this review, we discuss the main causes and features of pathogenesis of the hypoglycemic syndrome, as well as criteria of differential diagnosis and the possibility of introducing new diagnostic tests and markers.

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