General or Other | Hematology | Hypoglycemia (Symptom)
Hypoglycemia is the clinical syndrome that results from low blood sugar. The symptoms of hypoglycemia can vary from person to person, as can the severity. Classically, hypoglycemia is diagnosed by a low blood sugar with symptoms that resolve when the sugar level returns to the normal range.
The body needs fuel to work. One of its major fuel sources is sugars, which the body gets from what is consumed as either simple sugar or complex carbohydrates. For emergency situations (like prolonged fasting), the body stores a stash of sugar in the liver as glycogen. If this store is needed, the body goes through a biochemical process called gluco-neo-genesis (meaning to make new sugar) and converts these stores of glycogen to sugar. This backup process emphasizes that the fuel source of sugar is important (important enough for human beings to have developed an evolutionary system of storage to avoid a sugar drought).
While patients who do not have any metabolic problems can complain of symptoms suggestive of low blood sugar, true hypoglycemia usually occurs in patients being treated for diabetes (type 1 and type 2). Patients with pre-diabetes who have insulin resistance can also have low blood sugars on occasion if their high circulating insulin levels are further challenged by a prolonged period of fasting.
There are other rare causes for hypoglycemia, such as insulin producing tumours (insulinomas) and certain medications. These uncommon causes of hypoglycemia will not be discussed in this article, which will primarily focus on the hypoglycemia occurring with diabetes mellitus and its treatment. This is important for patients and physicians to recognize, especially as the goal for treating patients with diabetes become tighter blood sugar control.