Massachusetts General Hospital

Hypoglycemia (Low Blood Sugar)

What is hypoglycemia?

Hypoglycemia is a condition characterized by a glucose (blood sugar) level that is too low to effectively fuel the body's blood cells. Glucose is the main source of fuel for the body. According to the National Institute for Diabetes and Digestive and Kidney Diseases, the ideal range of blood sugar is approximately 70 to 120 mg/dL (milligrams of glucose per deciliter of blood). Blood sugar levels under 70 mg/dL are too low and are considered unhealthy.

Hypoglycemia may be a condition by itself, or may be a complication of diabetes or another disorder. It is most often seen as a complication of diabetes, which is sometimes referred to as insulin reaction.

What causes hypoglycemia?

Causes of hypoglycemia in people with diabetes may include the following:

• Too much medication

• A missed meal

• A delayed meal

• Too little food eaten as compared to the amount of insulin taken

Other causes of hypoglycemia are rare, but may occur in early pregnancy, after strenuous exercise, or during prolonged fasting. Hypoglycemia may also result from taking certain medications, abusing alcohol, or other rare causes, such as a tumor that produces insulin.

What are the symptoms of hypoglycemia?

The following are the most common symptoms of hypoglycemia. However, each individual may experience symptoms differently. The symptoms include:

• Shakiness

• Dizziness

• Sweating

• Hunger

• Headache

• Irritability

• Pale skin color

• Sudden moodiness or behavior changes, such as crying for no apparent reason

• Clumsy or jerky movements

• Difficulty paying attention, or confusion

• Tingling sensations around the mouth

The symptoms of hypoglycemia may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.

How is hypoglycemia diagnosed?

In addition to a complete medical history and physical examination, certain blood tests are used to diagnose hypoglycemia.

When a person with diabetes has symptoms of hypoglycemia, then the cause is usually diagnosed as a complication of diabetes, or insulin reaction. It is often the result of the causes listed above.

For those who have symptoms of hypoglycemia and do not have diabetes, the disorder is diagnosed by:

• Measuring blood glucose levels while the person is experiencing the symptoms

• Observing that the symptoms are relieved when the person eats food with a high content of sugar

Laboratory tests to measure insulin production may also be performed.

What is the treatment for hypoglycemia?

Specific treatment for hypoglycemia will be determined by your doctor based on:

• Your age, overall health, and medical history

• Extent of the condition

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the condition

• Your opinion or preference

For people with diabetes, the goal of treatment is to maintain a blood sugar level that is appropriate for each individual. This involves testing blood sugar often, learning to recognize the warning signs of low blood sugar, and treating the condition quickly, based on prior instructions from the doctor.

To treat low blood sugar immediately, you should eat or drink something that has sugar in it, such as orange juice, milk, or a hard candy.

For people who do not have diabetes, treatment (as directed by a doctor) may include:

• Avoiding foods high in carbohydrates

• Eating smaller meals more frequently

• Frequent snacks

• Eating a variety of healthy foods

• Regular exercise