Hypoglycemia refers to low blood sugar -- hypo meaning low and glycemia meaning sugar. Hypoglycemia is a disorder which is characterized by both sugar lows and highs. It can also be referred to as hypoadrenocorticism, which occurs when the adrenal glands fail to function properly. Hyperinsulinism refers to the secretion of excess insulin and neuroglycopenia describes a condition that results when brain cells are deprived of adequate sugar.