Diabetes Health Center

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Hypoglycemia, or low blood sugar, is most common in people who have diabetes. If you have already been diagnosed with diabetes and need more information about low blood sugar, see the topics:

• Type 1 Diabetes: Living With the Disease.
• Type 2 Diabetes.

What causes low blood sugar?

Your body uses hormones to keep your blood sugar in a normal range. But a long-term health problem that needs treatment can cause blood sugar to drop too low.

Hypoglycemia is most commonly a complication of diabetes treatment (diabetic hypoglycemia). You can develop hypoglycemia by taking too much insulin or other diabetes medicines.

Hypoglycemia may have other causes such as medicines, alcohol, stomach surgery, metabolic problems, and diseases of the pancreas, liver, kidneys, or adrenal glands.

What are the symptoms?

The symptoms can be different depending on how low your blood sugar level drops.

• Mild hypoglycemia can make you feel hungry or like you want to vomit. You could also feel jittery or nervous. Your heart may beat fast. You may sweat. Or your skin might turn cold and clammy.
• Moderate hypoglycemia often makes people feel short-tempered, nervous, afraid, or confused. Your vision may blur. You could also feel unsteady or have trouble walking.
• Severe hypoglycemia can cause you to pass out. You could have seizures. It could even cause a coma or death.

If you've had hypoglycemia during the night, you may wake up tired or with a headache. And you may have nightmares. Or you may sweat so much during the night that your pajamas or sheets are damp when you wake up.

How is hypoglycemia diagnosed?

To diagnose hypoglycemia, your doctor will do a physical exam and ask you questions about your health. You will need tests to check your blood sugar levels. Mostly, these are done while you are fasting. The time that you have to keep from eating can vary and may be 24 hours or more. Or you may learn how to take your own blood sugar when you notice symptoms that may be related to low sugar levels. Your doctor will also ask you about any medicines you take and whether you have recently lost or gained weight.

If a blood test shows that you have low blood sugar and you do not have diabetes, and if you have symptoms that go away after you eat a snack or drink with sugar in it, you probably have hypoglycemia.

Many people have symptoms of low blood sugar that is related to other medical problems. It is important to let your doctor do the tests to find out if your blood sugar is low enough to cause a problem.

How is it treated?

If you have symptoms of low blood sugar, you need to eat or drink something with sugar in it. For example, you could eat raisins, graham crackers, or candy. You could also drink skim milk, regular (not diet) soda, or fruit juice. You may also take glucose tablets.