Low blood sugar (hypoglycemia) can affect people who have diabetes. It occurs when there's too much insulin and not enough sugar (glucose) in your blood. Hypoglycemia is defined as blood sugar below 70 milligrams per deciliter (mg/dL) or 4 millimoles per liter (mmol/L). Several factors can cause hypoglycemia in people with diabetes, including taking too much insulin or other diabetes medications, skipping a meal, or exercising harder than usual.
Pay attention to early warning signs, so you can treat low blood sugar promptly. Treatment involves short-term steps — such as taking glucose tablets — to raise your blood sugar into a normal range.
Left untreated, diabetic hypoglycemia can lead to seizures and loss of consciousness. This is considered a medical emergency. Tell family and friends what symptoms to look for and what to do in case you're not able to treat diabetic hypoglycemia yourself.
Early warning signs and symptoms
Take your symptoms seriously. Diabetic hypoglycemia can increase the risk of serious — even deadly — accidents. Identifying and correcting the factors contributing to hypoglycemia, such as medications you take or irregular meal times, can prevent serious complications.
Informing people you trust, such as family, friends and co-workers, about hypoglycemia is important. Their knowledge of what symptoms to look for and what to do in case you're not able to treat hypoglycemia yourself can make a potentially difficult situation easier to manage.
Not everyone has the same symptoms or the same symptoms each time, so it's important to monitor your blood sugar levels regularly and keep track of how you're feeling when you do have low blood sugar. Some people don't experience any early symptoms. This is called hypoglycemia unawareness.
When to see a doctor
If you lose consciousness or can't swallow:
If you experience symptoms of hypoglycemia several times a week, see your doctor. You may need to change your medication dosage, change the type of medication you take or make other adjustments to your diabetes treatment program.
Hypoglycemia is most common among people who take insulin, but it can also occur if you're taking oral diabetes medications.
Common causes of diabetic hypoglycemia include:
Blood sugar regulation
Hypoglycemia also may result if, after taking your diabetes medication, you eat less than usual or exercise more than you normally do. Your doctor can work with you to prevent this imbalance by finding the dose that fits your regular eating and activity patterns.
If you ignore the symptoms of hypoglycemia too long, you may lose consciousness. That's because your brain needs glucose to function. Recognize the signs and symptoms of hypoglycemia early because untreated, hypoglycemia can lead to:
On the other hand, be careful not to overtreat your low blood sugar. If you do, you may cause your blood sugar level to rise too high (hyperglycemia). This, too, can be dangerous and eventually may damage your nerves, blood vessels and various organs.
Preparing for your appointment
If you experience symptoms of hypoglycemia several times a week, schedule an appointment with your doctor. Together you can determine what factors may be contributing to the hypoglycemia and decide what changes to make to prevent future episodes of low blood sugar.
It's a good idea to prepare for your appointment. Here's some information to help you get ready for your appointment, and to know what to expect from your doctor.
What you can do
For diabetic hypoglycemia, questions you may want to ask include:
Don't hesitate to ask any other questions.
What to expect from your doctor
Tests and diagnosis
You can determine if you have low blood sugar by using a blood glucose meter — a small computerized device that measures and displays your blood sugar level. You have hypoglycemia when your blood sugar level drops below 70 milligrams per deciliter (mg/dL) or 4 millimoles per liter (mmol/L).
It's important to record the date, time, test results, medication and dosage, and diet and exercise information each time you test your blood. Also, note any low blood sugar reactions. Your doctor diagnoses hypoglycemia using your records and looks for patterns to see how your medications and lifestyle affect your blood sugar.
Treatments and drugs
If you experience symptoms of low blood sugar but can't check your blood sugar level right away, treat yourself as though you have hypoglycemia. In fact, you might want to carry at least one sugary item with you at all times. It's also a good idea to wear a bracelet that identifies you as someone who has diabetes.
Check your blood sugar level again 15 to 20 minutes later. If it's still too low, eat or drink something sugary. When you feel better, be sure to eat meals and snacks as usual.
Glucagon is available by prescription only and comes in an emergency syringe kit. It contains one dose that has to be mixed before being injected. Store the glucagon at room temperature and be aware of the expiration date. Because vomiting can occur after an injection, you must be turned on your side to prevent choking if you're unconscious.
In 15 minutes you should be alert and able to swallow. You then need to eat. If you don't respond within 15 minutes, medical assistance should be called immediately.
Following are suggestions that can help prevent diabetic hypoglycemia:
Last Updated: 2012-04-03
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