By Dr Ananya Mandal, MD
The term hypoglycemia refers to an abnormally low level of blood sugar. Glucose provides the main source of energy which the various cells of the body use to perform their functions. When the glucose levels in the blood fall to below normal, which is generally considered to be below 4 mmol/L or 70 md/dL, a person may be referred to as hypoglycemic and could start to experience symptoms.
Causes of hypoglycemia
There are several causes of hypoglycemia, the most common being diabetes mellitus. In diabetics, there is underutilization of the blood glucose caused by either a lack of insulin or a resistance to insulin. The various cells of the body fail to absorb glucose properly from the blood, leading to a persistently high blood glucose level.
Such individuals are often prescribed insulin or other antihyperglycemic agents to try and normalize their blood sugar levels. However, if too much insulin is taken or if meals are missed or not correctly timed in conjunction with insulin medication, then the blood glucose level may fall too low.
Similarly, overexertion or the consumption of too much alcohol can deplete the blood sugar level in such individuals and raise the risk of hypoglycemia.
Other conditions that can cause hypoglycemia include hyperinsulinism (high levels of blood insulin), underactive pituitary gland and inborn errors of metabolism such as maple syrup urine disease. Other risk factors include prolonged exposure to cold temperatures causing hypothermia, sepsis, starvation and infection.
Symptoms of hypoglycemia
The symptoms of hypoglycemia arise due to over activity of the sympathetic nervous system triggered by the release of adrenalin in response to a falling blood sugar level. Some examples of such symptoms include:
Anxiety and feeling of dread
The brain is particularly vulnerable during a hypoglycemic event as it has very limited reserves of glucose and depends almost entirely on its availability in the body. In cases of severe hypoglycemia, a person may begin to lose consciousness, experience a seizure, slip into a coma or even die.
Hypoglycemia needs to be corrected as soon as possible whether a person has diabetes or not.
Blood sugar can be normalized by eating a glucose rich snack or drinking fruit juice. Dextrose tablets can also be taken. Diabetics are more prone to hypoglycemia and are advised to carry such food items at all times in case of a falling blood sugar that needs urgent correction.
In more severe cases where a person is losing consciousness, nothing should be put in their mouth due to the risk of choking and a 5% dextrose solution can be administered intravenously. An injection of the hormone glucagon may also be administered.
Reviewed by Sally Robertson, BSc
Last Updated: Jan 14, 2014