What are the symptoms of hypoglycemia?
Hypoglycemia causes symptoms such as
Hypoglycemia can also happen during sleep. Some signs of hypoglycemia during sleep include
What causes hypoglycemia in people with diabetes?
Hypoglycemia can occur as a side effect of some diabetes medications, including insulin and oral diabetes medications-pills-that increase insulin production, such as
Certain combination pills can also cause hypoglycemia, including
Other types of diabetes pills, when taken alone, do not cause hypoglycemia. Examples of these medications are
However, taking these pills along with other diabetes medications-insulin, pills that increase insulin production, or both-increases the risk of hypoglycemia.
In addition, use of the following injectable medications can cause hypoglycemia:
For more information about diabetes medications, see the National Diabetes Information Clearinghouse's booklet What I need to know about Diabetes Medicines, available at www.diabetes.niddk.nih.gov/dm/pubs/medicines_ez or by calling 1-800-860-8747.
Other Causes of Hypoglycemia
In people on insulin or pills that increase insulin production, low blood glucose can be due to
How can hypoglycemia be prevented?
Diabetes treatment plans are designed to match the dose and timing of medication to a person's usual schedule of meals and activities. Mismatches could result in hypoglycemia. For example, taking a dose of insulin-or other medication that increases insulin levels-but then skipping a meal could result in hypoglycemia.
To help prevent hypoglycemia, people with diabetes should always consider the following:
What to Ask the Doctor about Diabetes Medications
People who take diabetes medications should ask their doctor or health care provider
How is hypoglycemia treated?
Signs and symptoms of hypoglycemia vary from person to person. People with diabetes should get to know their signs and symptoms and describe them to their friends and family so they can help if needed. School staff should be told how to recognize a child's signs and symptoms of hypoglycemia and how to treat it.
People who experience hypoglycemia several times in a week should call their health care provider. They may need a change in their treatment plan: less medication or a different medication, a new schedule for insulin or medication, a different meal plan, or a new physical activity plan.
Prompt Treatment for Hypoglycemia
When people think their blood glucose is too low, they should check the blood glucose level of a blood sample using a meter. If the level is below 70 mg/dL, one of these quick-fix foods should be consumed right away to raise blood glucose:
Recommended amounts may be less for small children. The child's doctor can advise about the right amount to give a child.
The next step is to recheck blood glucose in 15 minutes to make sure it is 70 mg/dL or above. If it's still too low, another serving of a quick-fix food should be eaten. These steps should be repeated until the blood glucose level is 70 mg/dL or above. If the next meal is an hour or more away, a snack should be eaten once the quick-fix foods have raised the blood glucose level to 70 mg/dL or above.
For People Who Take Acarbose (Precose) or Miglitol (Glyset)
People who take either of these diabetes medications should know that only pure glucose, also called dextrose-available in tablet or gel form-will raise their blood glucose level during a low blood glucose episode. Other quick-fix foods and drinks won't raise the level quickly enough because acarbose and miglitol slow the digestion of other forms of carbohydrate
Help from Others for Severe Hypoglycemia
Severe hypoglycemia-very low blood glucose-can cause a person to pass out and can even be life threatening. Severe hypoglycemia is more likely to occur in people with type 1 diabetes. People should ask a health care provider what to do about severe hypoglycemia. Another person can help someone who has passed out by giving an injection of glucagon. Glucagon will rapidly bring the blood glucose level back to normal and help the person regain consciousness. A health care provider can prescribe a glucagon emergency kit. Family, friends, or coworkers-the people who will be around the person at risk of hypoglycemia-can learn how to give a glucagon injection and when to call 911 or get medical help.
Physical Activity and Blood Glucose Levels
Physical activity has many benefits for people with diabetes, including lowering blood glucose levels. However, physical activity can make levels too low and can cause hypoglycemia up to 24 hours afterward. A health care provider can advise about checking the blood glucose level before exercise. For those who take insulin or one of the oral medications that increase insulin production, the health care provider may suggest having a snack if the glucose level is below 100 mg/dL or adjusting medication doses before physical activity to help avoid hypoglycemia. A snack can prevent hypoglycemia. The health care provider may suggest extra blood glucose checks, especially after strenuous exercise.
Hypoglycemia When Driving
Hypoglycemia is particularly dangerous if it happens to someone who is driving. People with hypoglycemia may have trouble concentrating or seeing clearly behind the wheel and may not be able to react quickly to road hazards or to the actions of other drivers. To prevent problems, people at risk for hypoglycemia should check their blood glucose level before driving. During longer trips, they should check their blood glucose level frequently and eat snacks as needed to keep the level at 70 mg/dL or above. If necessary, they should stop for treatment and then make sure their blood glucose level is 70 mg/dL or above before starting to drive again.
Some people with diabetes do not have early warning signs of low blood glucose, a condition called hypoglycemia unawareness. This condition occurs most often in people with type 1 diabetes, but it can also occur in people with type 2 diabetes. People with hypoglycemia unawareness may need to check their blood glucose level more often so they know when hypoglycemia is about to occur. They also may need a change in their medications, meal plan, or physical activity routine.
Hypoglycemia unawareness develops when frequent episodes of hypoglycemia lead to changes in how the body reacts to low blood glucose levels. The body stops releasing the hormone epinephrine and other stress hormones when blood glucose drops too low. The loss of the body's ability to release stress hormones after repeated episodes of hypoglycemia is called hypoglycemia-associated autonomic failure, or HAAF.
Epinephrine causes early warning symptoms of hypoglycemia such as shakiness, sweating, anxiety, and hunger. Without the release of epinephrine and the symptoms it causes, a person may not realize that hypoglycemia is occurring and may not take action to treat it. A vicious cycle can occur in which frequent hypoglycemia leads to hypoglycemia unawareness and HAAF, which in turn leads to even more severe and dangerous hypoglycemia. Studies have shown that preventing hypoglycemia for a period as short as several weeks can sometimes break this cycle and restore awareness of symptoms. Health care providers may therefore advise people who have had severe hypoglycemia to aim for higher-than-usual blood glucose targets for short-term periods.
Being Prepared for Hypoglycemia
People who use insulin or take an oral diabetes medication that can cause low blood glucose should always be prepared to prevent and treat low blood glucose by
Source: American Diabetes Association. Standards of Medical Care in Diabetes-2008. Diabetes Care. 2008;31:S12-S54.
For people with diabetes, a blood glucose level below 70 mg/dL is considered hypoglycemia.
Hypoglycemia in People Who Do Not Have Diabetes
Two types of hypoglycemia can occur in people who do not have diabetes:
Symptoms of both reactive and fasting hypoglycemia are similar to diabetes-related hypoglycemia. Symptoms may include hunger, sweating, shakiness, dizziness, light-headedness, sleepiness, confusion, difficulty speaking, anxiety, and weakness.
To find the cause of a patient's hypoglycemia, the doctor will use laboratory tests to measure blood glucose, insulin, and other chemicals that play a part in the body's use of energy.
A blood glucose level below 70 mg/dL at the time of symptoms and relief after eating will confirm the diagnosis. The oral glucose tolerance test is no longer used to diagnose reactive hypoglycemia because experts now know the test can actually trigger hypoglycemic symptoms.
Causes and Treatment
A few causes of reactive hypoglycemia are certain, but they are uncommon. Gastric-or stomach-surgery can cause reactive hypoglycemia because of the rapid passage of food into the small intestine. Rare enzyme deficiencies diagnosed early in life, such as hereditary fructose intolerance, also may cause reactive hypoglycemia.
To relieve reactive hypoglycemia, some health professionals recommend
The doctor can refer patients to a registered dietitian for personalized meal planning advice. Although some health professionals recommend a diet high in protein and low in carbohydrates, studies have not proven the effectiveness of this kind of diet to treat reactive hypoglycemia.
Causes and Treatment
Medications. Medications, including some used to treat diabetes, are the most common cause of hypoglycemia. Other medications that can cause hypoglycemia include
If using any of these medications causes a person's blood glucose level to fall, the doctor may advise stopping the medication or changing the dose.
Alcoholic beverages. Drinking alcoholic beverages, especially binge drinking, can cause hypoglycemia. The body's breakdown of alcohol interferes with the liver's efforts to raise blood glucose. Hypoglycemia caused by excessive drinking can be serious and even fatal.
Critical illnesses. Some illnesses that affect the liver, heart, or kidneys can cause hypoglycemia. Sepsis, which is an overwhelming infection, and starvation are other causes of hypoglycemia. In these cases, treating the illness or other underlying cause will correct the hypoglycemia.
Hormonal deficiencies. Hormonal deficiencies may cause hypoglycemia in very young children, but rarely in adults. Shortages of cortisol, growth hormone, glucagon, or epinephrine can lead to fasting hypoglycemia. Laboratory tests for hormone levels will determine a diagnosis and treatment. Hormone replacement therapy may be advised.
Tumors. Insulinomas are insulin-producing tumors in the pancreas. Insulinomas can cause hypoglycemia by raising insulin levels too high in relation to the blood glucose level. These tumors are rare and do not normally spread to other parts of the body. Laboratory tests can pinpoint the exact cause. Treatment involves both short-term steps to correct the hypoglycemia and medical or surgical measures to remove the tumor.
Conditions occurring in infancy and childhood. Children rarely develop hypoglycemia. If they do, causes may include the following:
*A personal blood glucose monitor cannot be used to diagnose reactive hypoglycemia.
Points to Remember
Hypoglycemia Unrelated to Diabetes
Hope through Research
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) was established by Congress in 1950 as one of the National Institutes of Health of the U.S. Department of Health and Human Services. The NIDDK conducts and supports research in diabetes, glucose metabolism, and related conditions. Researchers supported by the NIDDK are investigating topics such as the causes of hypoglycemia and whether use of continuous glucose monitoring devices can help prevent hypoglycemia.
Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research. For information about current studies, visit www.ClinicalTrials.gov.
For More Information
National Diabetes Information Clearinghouse
The National Diabetes Information Clearinghouse (NDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services. Established in 1978, the Clearinghouse provides information about diabetes to people with diabetes and to their families, health care professionals, and the public. The NDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about diabetes.
Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This fact sheet was reviewed by Vivian A. Fonseca, M.D., F.R.C.P., Tulane University Health Sciences Center, New Orleans, LA; Catherine L. Martin, M.S., A.P.R.N., B.C.-A.D.M., C.D.E., University of Michigan Health System, Ann Arbor, MI; and Neil H. White, M.D., C.D.E., Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, MO.
This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.
NIH Publication No. 09-3926