INTRODUCTION — Hypoglycemia, also known as low blood sugar, occurs when levels of glucose (sugar) in the blood are too low. Hypoglycemia is common in people with diabetes who take insulin or oral medications that cause insulin secretion. People with type 2 diabetes often use diet control or oral medications that do not cause insulin secretion; hypoglycemia does not occur in these patients.
Hypoglycemia happens when a person with diabetes does one or more of the following: Takes too much insulin (or drugs that cause insulin secretion) Does not eat enough food Exercises vigorously without eating a snack or decreasing the dose of insulin beforehand Waits too long between meals Drinks excessive alcohol, although even moderate alcohol use can increase the risk of hypoglycemia in patients with type 1 diabetes
SYMPTOMS — The symptoms of hypoglycemia vary from person to person, and can change over time. Patients who drink excessive amounts of alcohol, are tired, or who take beta-blocking medications may not notice their symptoms, or may not recognize that the symptoms are due to hypoglycemia.
During the early stages of a hypoglycemic episode, symptoms may include: Sweating Tremor Hunger Anxiety
If untreated, symptoms can become more severe, and can include: Lack of coordination Weakness Lethargy Blurred vision Bizarre behavior or personality change Confusion Unconsciousness or seizure
When possible, hypoglycemia should be confirmed by measuring the blood glucose level. (See "Patient information: Self-blood glucose monitoring"). A blood glucose below 60 mg/dL, in the presence of symptoms, indicates hypoglycemia for most patients.
Some patients with diabetes can experience hypoglycemia at slightly higher blood glucose levels. Patients whose blood glucose levels are high for long periods of time may have symptoms of low blood glucose and feel poorly when levels approach 100 mg/dL. These patients should intensify their diabetic regimen to get blood glucose levels into a range that is closer to normal. This will lower the blood glucose level at which a patient feels symptoms.
Hypoglycemia unawareness — Hypoglycemia unawareness occurs when a person does not have the early symptoms of low blood glucose. As a result, the person cannot respond in the early stages, and severe signs of hypoglycemia, such as loss of consciousness or seizures, are more likely. It is a common occurrence, especially in patients who have had type 1 diabetes for greater than five to 10 years.
Hypoglycemia and hypoglycemia unawareness occur more frequently in patients who tightly control their blood glucose levels with insulin (called intensive therapy, show figure 1). Frequent low blood glucose levels reduce the production of the hormones which produce symptoms of low blood glucose.
Hypoglycemia unawareness can also occur in patients who take medications that stimulate insulin secretion (for example Micronase® [glyburide]), especially if they are elderly or have impaired kidney or heart function who take an oral medication that stimulates insulin secretion (show figure 2).
Nocturnal hypoglycemia — Low blood glucose that occurs when a person is sleeping (nocturnal hypoglycemia) can disrupt sleep and often goes unrecognized. Nocturnal hypoglycemia is a form of hypoglycemia unawareness. Thus, a person with nocturnal hypoglycemia is less likely to have symptoms that alert them to the need for treatment. Nocturnal hypoglycemia can be difficult to diagnose, and can increase the risk of hypoglycemia unawareness in the 48 to 72 hours that follow.
PREVENTION — The best way to prevent hypoglycemia is to monitor blood glucose levels frequently and be prepared at all times to treat it promptly. The patient as well as a close friend or relative need to learn the symptoms, and patients at risk for hypoglycemia (those treated with insulin and some oral medications, show figure 2) should always carry glucose tablets, hard candy, or other sources of fast-acting carbohydrate. Glucose tablets are recommended since they have a pleasant taste, but are not likely to be eaten for reasons other than hypoglycemia. Candy can be tempting to eat, even when blood glucose levels are normal, especially for children with diabetes.
Hypoglycemia can be frightening and unpleasant, and it is common for patients who have experienced an episode of severe hypoglycemia to be fearful of future episodes. Patients who experience this fear may keep their blood glucose excessively high, which can lead to long term complications.
It may be helpful to discuss fears of hypoglycemia with a healthcare provider. In addition, patients should ask about blood glucose awareness education and training in the use of glucagon, an injectable drug that raises blood sugar levels quickly. Blood glucose awareness training can improve a patient's ability to recognize low blood glucose earlier, which may help to prevent episodes of severe hypoglycemia.
TREATMENT — While the blood glucose level should be tested as soon as possible, treatment should not be delayed if monitoring equipment (blood glucose meter, test strips, lancet) is not readily available. Treatment of hypoglycemia should be quick, especially if blood glucose levels are less than 40 mg/dL.
As soon as symptoms are noted, a patient should eat 10 to 15 grams of fast-acting carbohydrate. Examples include: Three to four glucose tablets Six to eight hard candies 1/2 cup fruit juice
This amount of food is usually enough to raise the blood glucose into a safe range without causing high blood glucose levels (called hyperglycemia). Foods that contain fat (like candy bars) or protein (cheese) should initially be avoided, since they slow down the body's ability to absorb glucose.
After 15 minutes, the blood glucose level should be measured again. It is important to wait since it takes time for the body to absorb glucose and for symptoms to resolve. If the blood glucose level is below 60 mg/dL, or if symptoms persist, another 10 to 15 grams of fast-acting carbohydrate should be eaten.
Once symptoms and blood glucose levels are under control, a snack may be needed to control blood glucose levels until the next meal. If the next meal is more than one hour away or the patient has just completed vigorous exercise, a snack including 15 grams of carbohydrate and 1 ounce of protein should be eaten. Examples of this include crackers with cheese or one-half of a sandwich with peanut butter. It is important not to eat too much, as this can raise blood glucose levels above the target level.
Glucagon — If hypoglycemia is severe, the patient may become unconscious or unable to eat. A close friend or relative should be trained to recognize severe hypoglycemia and treat it quickly. Dealing with a loved one who is pale, sweaty, acting in a bizarre way, or unconscious and convulsing can be scary. An injection of glucagon stops these symptoms quickly.
Glucagon is a hormone that raises blood glucose levels. Glucagon is available in emergency kits, which can be bought with a prescription in a pharmacy (show picture 1). Directions are included in each kit; a roommate, spouse, or parent should familiarize themselves with the injection procedure before an emergency occurs.
It is important that the glucagon kit is easy to locate, is not expired, and that the friend or relative is able to stay calm. It is important that the kit is refilled when the expiration date approaches, though administering an expired kit is unlikely to cause harm.
Procedure — Glucagon is injected subcutaneously (under the skin) of the thigh or abdomen. The injection sites and technique are similar to an insulin injection. Remove the needle protector and inject the entire content of the syringe (a clear solution) into the glucagon powder. Do not remove the plastic clip on the syringe. Remove syringe from the bottle. Swirl the mixture gently until the powder is dissolved. The solution should be clear. Do not use the solution if it is discolored. Hold the bottle upside down and withdraw the contents into the syringe (1 mg mark on syringe for adults and children over 44 pounds [20 kilograms]). Children under 44 pounds need one-half the dose, and only 1/2 the solution should be withdrawn (0.5 mg mark on syringe). Cleanse the injection site (abdomen or thigh) with an alcohol swab (show figure 3) Insert the needle into the skin (show picture 2). Press the plunger to inject the glucagon. Withdraw the needle, and replace the syringe in the storage case (do not attempt to re-cap the needle). Press lightly at the injection site. Turn the patient to his or her side. This prevents choking if the patient vomits.
Symptoms should resolve within 10 to 15 minutes, although nausea and vomiting may follow 60 to 90 minutes later. As soon as the patient is awake and able to swallow, a fast-acting carbohydrate such as glucose tablets or juice should be offered. After the patient begins to feel better, he or she should eat a snack with protein, such as crackers and cheese or a peanut butter sandwich.
If the patient is not conscious within 10 minutes, another glucagon injection should be given, if a second kit is available. Emergency help should be called immediately.
WHEN TO SEEK HELP — A family member or friend should take a patient to the hospital or call for emergency assistance (911 in many US communities) immediately if the patient: Remains confused or in an altered mental state after being treated with glucagon Is unconscious (or nearly unconscious) and glucagon is not available Continues to have low blood glucose despite eating adequate amounts of a fast-acting carbohydrate or receiving glucagon
Once in a hospital or ambulance, intravenous glucose is given to raise levels immediately.
FOLLOW UP CARE — After the blood glucose level is normal and symptoms are gone, a patient can usually resume his or her normal activities. A patient who required glucagon should speak with his or her healthcare provider. This can help to identify the cause of a severely low blood glucose level, and adjustments can be made to prevent future reactions. Patients who require emergency care may be observed for a few hours before being released. A friend or relative should drive the patient home.
Patients should be especially careful in the first 48 to 72 hours after a hypoglycemic episode, because his or her ability to recognize the symptoms of low blood glucose may be impaired. In addition, the body's ability to counteract low blood glucose levels is decreased.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
National Institute of Diabetes & Digestive & Kidney Diseases
(www.niddk.nih.gov)
American Diabetes Association (ADA)
(800)-DIABETES (800-342-2383)
(www.diabetes.org)
The Endocrine Society
(www.endo-society.org)
The Hormone Foundation
(www.hormone.org/public/diabetes.cfm, available in English and Spanish)
[1-4]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Cox, DJ, Gonder-Frederick, L, Julian, DM, Clarke, W. Long-term follow-up evaluation of blood glucose awareness training. Diabetes Care 1994; 17:1.
2. Fanelli, CG, Paramore, DS, Hershey, T, et al. Impact of nocturnal hypoglycemia on hypoglycemic cognitive dysfunction in type 1 diabetes. Diabetes 1998; 47:1920.
3. Irvine, AA, Cox, D. Gonder-Frederick, L. Fear of hypoglycemia: Relationship to physical symptoms in patients with insulin-dependent diabetes. Health Psych 1992; 11:135.
4. Weinger, K, Kinsley, BT, Levy, CJ, et al. The perception of safe driving ability during hypoglycemia in patients with type 1 diabetes mellitus. Am J Med 1999; 107:246.
No comments:
Post a Comment