What is low blood sugar?

Low blood sugar is a condition that happens when the level of sugar in a person's blood gets too low. Some symptoms of low blood sugar are mild, such as sweating or feeling hungry. Others are severe, such as passing out. Another word for low blood sugar is "hypoglycemia."

Low blood sugar happens most often in people with diabetes. It is uncommon in people who do not have diabetes. People without diabetes might feel like they have low blood sugar sometimes, but they most likely don't.

What causes low blood sugar in people without diabetes?

Causes of low blood sugar in people without diabetes include:

  • Certain medicines
  • Drinking alcohol, especially drinking a lot over a few days
  • Certain illnesses that affect the liver or kidneys
  • Anorexia nervosa – This is an eating disorder that makes people lose more weight than is healthy.
  • Growths or problems in the pancreas – The pancreas is an organ that makes hormones and juices that help the body break down food
  • Hormone conditions that some babies are born with

What are the symptoms of low blood sugar?

Symptoms of low blood sugar can include:

  • Sweating or shaking
  • Feeling hungry
  • Feeling worried

If low blood sugar levels are not treated, severe symptoms can occur. These can include:

  • A headache, blurry vision, or feeling dizzy
  • Feeling weak or having trouble walking
  • Acting confused or not thinking clearly
  • Passing out

Some people have symptoms within a few hours of eating a meal. Other people have symptoms when they haven't eaten for many hours.

How do I know if I have low blood sugar?

To be diagnosed with low blood sugar, you must meet certain conditions. You must:

  • Have symptoms of low blood sugar
  • Have a low blood sugar level when you have the symptoms
  • Feel better after you eat something that raises your blood sugar level to normal

To check if you meet these conditions, your doctor will do blood tests when you have symptoms of low blood sugar. Your doctor might have you do things to bring on your symptoms so he or she can do the tests. For example, he or she might have you stop eating for a certain amount of time.

After your doctor knows for sure that you get low blood sugar, he or she will look for the cause. To do this, he or she might order tests, including:

  • Other blood tests
  • A CT scan, MRI scan, or ultrasound – These are imaging tests that can create pictures of the inside of the body.

How is low blood sugar treated?

Treatment for low blood sugar involves both raising your blood sugar and treating the cause of your low blood sugar.

Your doctor or nurse will teach you how you can raise your blood sugar when it gets low. People usually raise their blood sugar by eating or drinking quick sources of sugar:

  • 3 or 4 glucose tablets
  • ½ cup of juice or regular soda (not sugar-free)
  • 2 tablespoons of raisins
  • 4 or 5 saltine crackers
  • 1 tablespoon of sugar
  • 1 tablespoon of honey or corn syrup
  • 6 to 8 hard candies

Depending on your condition, your doctor might recommend that you carry a quick source of sugar with you at all times in case you need it.

If your blood sugar is so low that you are confused or passing out, and you are not able to eat anything, you will need to be treated with glucagon. Glucagon is a hormone that can quickly raise blood sugar levels and stop severe symptoms. It comes as a shot or a nose spray. If your doctor recommends that you carry glucagon with you, he or she will tell you when and how to use it. Family members should also learn how to give you glucagon. That way a family member can give it to you if you can't do it yourself.

Your doctor will also treat the condition that's causing your low blood sugar, if it can be treated. For example, if a medicine is causing your low blood sugar, your doctor can change or stop your medicine. If you have a growth in your pancreas, your doctor might do surgery to remove the growth.

When should I go to a hospital or call for an ambulance?

A family member or friend should take you to a hospital or call for an ambulance if you:

  • Still have low blood sugar after you have had a quick source of sugar
  • Are still confused 15 minutes after being treated with a dose of glucagon
  • Have passed out and there is no glucagon nearby

If you have low blood sugar, do not try to drive yourself to the hospital. Driving with low blood sugar can be dangerous. Once you are in the hospital or ambulance, you will be given fluids with sugar into your vein. This treatment will raise your blood sugar level immediately.

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