Hypoglycemia (Low Blood Sugar) in People Without Diabetes
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Hypoglycemia, or low blood sugar, is most common in people with diabetes. If you have already been diagnosed with diabetes and need more information about low blood sugar, see the topics:
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.
People with diabetes often deal with low blood sugar. It’s not as common in people who don't have diabetes, but it can happen. It could be caused by:
- Medicines such as monoamine oxidase inhibitors (used to treat depression), quinine sulfate (used to treat malaria), and aspirin.
- Drinking too much alcohol.
- Diseases that affect the pancreas, liver, kidneys, adrenal glands, or other organs.
- Metabolic problems that run in families.
- Problems caused by stomach surgery.
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. 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 if you have symptoms that go away after you eat a snack or drink with sugar in it, you probably have hypoglycemia.
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.
It’s a good idea to find out about health problems or situations that can lead to low blood sugar. It’s also important to pay attention to your health and lifestyle. For example, talk to your doctor to see if you can change your diet, change the medicines you take, or change the way you exercise. In some cases, treating the health problem that is causing low blood sugar can prevent future problems.
What should you do in an emergency?
If mild or moderate hypoglycemia isn't treated right away, it can turn into severe hypoglycemia. People with severe hypoglycemia usually pass out. If you pass out, someone should call 911 right away. It’s a good idea to teach your family, friends, and coworkers ahead of time about the symptoms of low blood sugar so they'll know what to do.
Frequently Asked Questions
Learning about hypoglycemia:
The symptoms of hypoglycemia may vary from episode to episode because low blood sugar can be mild, moderate, or severe. Increasingly severe symptoms appear as the blood sugar level falls.
In healthy people, fasting blood sugar levels are usually between 70 and 99 mg/dL.
Symptoms of mild low blood sugar usually occur when blood sugar falls below 70 mg/dL and may include:
- Extreme hunger.
- Feeling nervous or jittery.
- Cold, clammy, wet skin and/or excessive sweating not caused by exercise.
- A rapid heartbeat (tachycardia).
- Numbness or tingling of the fingertips or lips.
If blood sugar continues to fall, the nervous system will be affected. Symptoms usually occur when the blood sugar falls below 55 mg/dL and may include:
- Mood changes, such as irritability, anxiety, restlessness, or anger.
- Confusion, difficulty in thinking, or inability to concentrate.
- Blurred vision, dizziness, or headache.
- Weakness, lack of energy.
- Poor coordination.
- Difficulty walking or talking, such as staggering or slurred speech.
- Fatigue, lethargy, or drowsiness.
The symptoms of severe low blood sugar develop when blood sugar falls below 35 mg/dL to 40 mg/dL and may include:
- Seizures or convulsions.
- Loss of consciousness, coma.
- Low body temperature (hypothermia).
Prolonged severe hypoglycemia can cause irreversible brain damage and heart problems, especially in people who already have coronary artery disease. If emergency medical treatment is not provided, severe hypoglycemia can be fatal.
What to think about
Different people may have symptoms of mild, moderate, or severe hypoglycemia at varying blood sugar levels. Although the blood sugar levels listed above are typical, they may not apply to everyone. If your blood sugar drops suddenly, you may have symptoms even if your level is in the normal range.
A number of medical conditions can cause symptoms similar to those of hypoglycemia. Your doctor will use blood tests and other measures to make sure another condition isn't causing your symptoms.
Exams and Tests
Doctors diagnose hypoglycemia using a medical history, physical exam, and tests to check the blood sugar level.
In general, you are diagnosed with hypoglycemia if you have a low blood sugar level and symptoms that go away after you have taken glucose to restore your blood sugar level.1
Your doctor will ask questions about:
- What symptoms you typically have—how long they last, when they occur, how often they occur, and what happens to your symptoms when you eat something.
- Past medical treatments, current medical conditions, and whether you are taking medicines (bring all medicines, both prescription and nonprescription, to your appointment for review) or receiving other treatment.
- Diet and nutrition, such as what and when you eat, and whether you have had recent changes in your eating or bowel habits.
- Whether you have gained or lost weight recently.
Because an episode of hypoglycemia can impair mental functioning, your doctor may also want to talk to friends or relatives who have seen your symptoms.
Your doctor also will look for conditions that may cause hypoglycemia, including signs of:
- Liver disease, such as an enlarged liver.
- Kidney disease, such as swelling (edema), and too much urea in the blood.
- Malnutrition, such as extreme weight loss.
- Adrenal gland disease, such as too much pigment (color) in the skin and/or low blood pressure.
Primary laboratory tests
Often hypoglycemia is a complication of diabetes treatment. If you are not being treated for diabetes or another obvious cause of low blood sugar, you will have tests to confirm hypoglycemia. Ideally, your doctor would like to do these tests when you are experiencing symptoms. But because this is usually not possible, you probably will have tests that try to reproduce symptoms. These tests are usually done in a clinic or a hospital.
In some cases, home glucose monitors, which are often used by people who have diabetes, may be used to evaluate possible hypoglycemia. But a low blood sugar reading needs to be confirmed by these formal laboratory tests:
- Overnight fast. You will be asked not to eat overnight, and you will have your blood sugar and insulin levels checked the following morning. In many cases, this test will tell your doctor if you have fasting hypoglycemia.
- Prolonged supervised fast. The primary test for hypoglycemia is a prolonged (48- to 72-hour) supervised fast. You will be asked to fast until the symptoms of moderate low blood sugar develop or until blood glucose levels drop below 45 mg/dL. If at the end of 72 hours you do not have low blood sugar, you may be asked to exercise for 30 minutes. This test also can help your doctor find out why confirmed hypoglycemia is occurring.
During the prolonged supervised fast test, your blood is drawn at regular intervals to monitor how well your body controls blood sugar levels. Laboratory tests measure substances in the blood, such as glucose, insulin, and C-peptide.
A urine or blood test may be done to look for substances called ketones that the body produces when it breaks down fat for energy. Insulin prevents the production of ketones. If you have low blood sugar from too much insulin, your body will not produce ketones. In people who have normal insulin release, prolonged fasting causes a drop in insulin and an increase in ketone production.
If the suspected cause is rapid emptying of the stomach after a meal (reactive or alimentary hypoglycemia) or a tumor in the pancreas or other part of the body, you may have imaging tests, such as ultrasound, CT scan, or MRI, to examine your stomach, pancreas, or other internal organs. In some cases pancreatic tumors are quite small, so an imaging test in which a dye is injected into the blood vessels (angiography) may be used to locate the tumor. Other imaging tests use radioactive proteins that bind to tumors. This helps the doctor locate a tumor. Imaging tests may be needed regularly for several years, because such tumors can be hard to locate.
What to think about
The oral glucose tolerance test should not be used to evaluate possible nonfasting (postprandial) hypoglycemia. This test does not provide consistent and reliable results when it is used to screen for hypoglycemia.
You can treat a sudden (acute) episode of hypoglycemia by eating or drinking some form of sugar to return your blood sugar to a normal range. This treatment is usually all that is necessary for an isolated episode of hypoglycemia, such as from prolonged fasting or strenuous exercise without adequate food.
Hypoglycemia caused by a long-term (chronic) health condition requires treatment of the long-term health condition.
Treatment of acute hypoglycemia
- If you are conscious and able to respond when symptoms develop, eat or drink some form of sugar. Drink fruit juice or sugared (non-diet) soda pop or eat sugar in the form of candy, cubes, or tablets, or other quick-sugar foods.
- Make sure your family members, coworkers, and others close to you are aware that you may have episodes of hypoglycemia, so they can help you. Emergency treatment for people who do not use insulin usually does not require glucagon, but it may be needed in rare cases.
- Tell the people close to you that they should call 911 or other emergency services if you become sleepy or unconscious. They also should seek emergency help if you are not unconscious but they do not know how to give you an injection of glucagon. Always have a medical alert bracelet or tag with you. Medical alert jewelry can be bought in pharmacies or on the Internet.
- Severe cases of hypoglycemia may require hospitalization. You may be given additional glucose in a vein (intravenously) until your blood sugar level is stable in the normal range. This could take several days, depending on the cause.
- Future episodes of low blood sugar may be avoided if you change the behavior or situation that led to the hypoglycemia. If medicine causes hypoglycemia, you may be able to stop using it or change how it is used. Talk to your doctor about how to avoid future episodes of low blood sugar.
- Remember that low blood sugar may be only temporarily corrected with acute treatment, and you may need additional treatment. If you have a glucose meter, you should recheck your blood sugar level in 10 to 15 minutes. If you do not have a blood glucose meter, you should be alert for the return of low blood sugar symptoms and be prepared to seek emergency care.
Treatment of hypoglycemia caused by another condition
If you have low blood sugar caused by a chronic health condition, your symptoms will be treated the same as those of acute hypoglycemia. After you have recovered from the immediate symptoms, you will need treatment for the condition that is causing hypoglycemia. In many situations, after the cause is identified, new episodes of hypoglycemia can be prevented.
Low blood sugar may have a long-term cause that can be cured, such as some endocrine disorders or diseases of the liver, adrenal glands, or pancreas. Effective long-term treatment of an insulin-producing tumor in the pancreas (insulinoma) usually requires surgery.
Even if the condition that is causing your hypoglycemia is not curable, treatment often can prevent episodes of low blood sugar. Talk to your doctor about whether you can modify your diet (what, when, or how much you eat), change the dosage or types of medicines you take, or modify your physical activity (such as when and how hard you exercise).
This type of management is most common for people who have diabetes, other chronic health conditions that may require long-term treatment (liver disease, kidney failure, or endocrine disorders), and inherited enzyme or hormone deficiencies. It may also be useful for people who have alcohol-related illnesses.
If you are at risk for hypoglycemia, you need to know about health conditions or situations that may lead to low blood sugar and how to deal with them. Proper attention to your health and lifestyle can help you prevent hypoglycemia.
Learn to recognize the early symptoms of hypoglycemia and to take steps to deal with low blood sugar immediately.
When your blood sugar drops too low, drink fruit juice or sugared (non-diet) soda pop. Or eat sugar in the form of candy, cubes, or tablets. Or eat other quick-sugar foods.
Members of your household, close friends, and coworkers also should know the symptoms of low blood sugar and learn about emergency care. Wear medical information on a badge or bracelet if you are at risk for moderate or severe hypoglycemia, in case an episode occurs when you are away from family, friends, or caregivers.
Emergency care for low blood sugar for people who are not taking insulin includes consuming some kind of quick-sugar food, such as fruit juice, as long as you are able to swallow. (Use this information if you do not know whether a person with hypoglycemia takes insulin.)
Health and lifestyle management to avoid hypoglycemia
When hypoglycemia occurs because of an isolated, short-term cause such as prolonged fasting or strenuous exercise, further medical treatment is usually not needed. You may simply need to talk with your doctor about how to avoid such behaviors or situations.
When hypoglycemia has a chronic cause that is not curable, treatment of the condition often can prevent episodes of low blood sugar. Talk with your doctor about:
- Modifying your diet with a long-term meal plan (what, when, and how much you eat).
- Changing the dosage or types of medicines you take.
- Modifying the timing and level of physical activity (such as when and how hard you exercise).
- Keeping a diary of low blood sugar symptoms (when they occur and what and when you last ate).
Your doctor will want to see you for a physical exam every year (annual) or more often if your symptoms become frequent. You and your doctor will discuss your home blood sugar monitoring records and your diary of your symptoms.
Other Places To Get Help
|National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)|
|Building 31, Room 9A06|
|31 Center Drive, MSC 2560|
|Bethesda, MD 20892-2560|
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) provides information and conducts research on a wide variety of diseases as well as issues such as weight control and nutrition.
- Cryer PE (2008). Glucose homeostasis and hypoglycemia. In HM Kronenberg et al., eds., Williams Textbook of Endocrinology, 11th ed., pp. 1503–1533. Philadelphia: Saunders Elsevier.
Other Works Consulted
- Amiel SA (2005). Iatrogenic hypoglycemia. In CR Kahn, et al., eds., Joslin's Diabetes Mellitus, 14th ed., pp. 671–686. Philadelphia: Lippincott Williams and Wilkins.
- Cryer PE (2008). Hypoglycemia. In AS Fauci et al., eds., Harrison's Principles of Internal Medicine, 17th ed., vol. 2, pp. 2305–2310. New York: McGraw-Hill.
- Glaser B, Leibowitz G (2005). Hypoglycemia. In CR Kahn et al., eds., Joslin's Diabetes Mellitus, 14th ed., pp. 1147–1175. Philadelphia: Lippincott Williams and Wilkins.
- Service FJ (2007). Hypoglycemia. In DC Dale, DD Federman, eds., ACP Medicine, section 3, chap. 9. New York: WebMD.
|Author||Bets Davis, MFA|
|Editor||Susan Van Houten, RN, BSN, MBA|
|Associate Editor||Pat Truman, MATC|
|Primary Medical Reviewer||Caroline S. Rhoads, MD - Internal Medicine|
|Specialist Medical Reviewer||David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism|
|Last Updated||April 6, 2009|
Last Updated: April 6, 2009