Postprandial Hypoglycemia

Postprandial hypoglycemia is a syndrome secondary to disorders in which hypoglycemia is manifested within 5 hours after a meal (1). It is classified into two types depending on the time of occurrence, i.e., ‘early,’ with onset within 2 hours, and ‘late,’ occurring between 3 and 5 hours after a meal. The early variety is thought to be secondary to abnormally rapid gastric emptying, whereas late postprandial hypoglycemia is frequently deemed to be a precursor to the onset of type 2 diabetes mellitus (1-14). Causes of late postprandial hypoglycemia also include disorders manifesting as fasting hypoglycemia, such as factitious hypoglycemia due to exogenous insulin administration or surreptitious use of insulin secretogogues, e.g, sulfonylureas, glinides, or other hypoglycemic agents, insulinoma, islet cell hyperplasia, autoimmune hyperinsulinemia, hyperinsulinemia caused by drugs and toxins, excess of circulating IGF2 secreted by non-pancreatic tumors, adrenal or pituitary hypofunction, advanced liver dysfunction, and end-stage renal disease(15-29 ) Several rare disorders, including some congenital syndromes, e.g., glycogen storage disorders, can also cause late postprandial hypoglycemia(30). In contrast, early postprandial hypoglycemia occurs only postprandially and usually is noted in subjects following upper gastrointestinal surgery, including bariatric procedures, hyperthyroidism, etc (1,21,26,31,32). In some subjects, it occurs without an obvious apparent cause and is therefore termed ‘idiopathic reactive hypoglycemia.’ Arguably, many endocrinologists approve of this syndrome, whereas others question its existence and call it ‘postprandial syndrome,’ probably because of the debate over the diagnosis of hypoglycemia itself (8,21,29). Hypoglycemia presents with manifestations of increased sympathetic activity, i.e., anxiety, jitters, palpitations, dizziness, tremor, weakness, drenching perspiration, hunger, systolic hypertension, mydriasis, etc., attributed to prompt release of catecholamines, which is documented to occur with a fall of blood sugar to lower than 70 mg /dl (29,34,35). Manifestations more seriously detrimental to life, i.e., of a neuroglycopenic nature, include convulsion, confusion, coma, or other altered states of consciousness, and transient CNS manifestations, including hemiparesis. Cardiac manifestations include symptomatic coronary artery disease, i.e., angina pectoris, arrhythmias, or even myocardial infarction following extreme lowering of blood sugars, usually to concentrations below 50 mg/dl (35).