DEAR MAYO CLINIC: What could cause a person without diabetes to become hypoglycemic? Would keeping track of my blood levels throughout the day be beneficial?
ANSWER: Diabetes and the medications people take for it are by far the most common causes of hypoglycemia, or low blood sugar. There are other reasons your blood sugar may be low, however. Keeping track of your blood sugar at home can be a good step in some cases. But you should do so only after you have been evaluated for low blood sugar by an endocrinologist — a doctor who specializes in diabetes and other hormone-related disorders.
Hypoglycemia happens when you do not have enough sugar, or glucose, in your blood. People sometimes talk casually about having low blood sugar. True hypoglycemia is a serious condition that can lead to severe medical problems if left untreated.
In addition to a thorough physical exam and review of your medical history, three factors typically are involved in a diagnosis of hypoglycemia. The first is having symptoms of hypoglycemia. Common symptoms often include shakiness, sweating, confusion and visual problems, such as double or blurry vision. The second is doing a blood test to analyze your blood sugar level. The third involves confirming that your symptoms go away when blood sugar levels return to normal.
All three of these components are important for an accurate diagnosis of hypoglycemia. For example, if your blood sugar is low, but it does not lead to symptoms, then treatment usually is not necessary. Some people just have occasional low blood sugar that is not a cause for concern.
If you have symptoms but blood tests at your doctor’s office show a normal level of blood sugar, then additional investigation may be necessary. If your symptoms are mild, tracking blood sugar at home using a blood testing machine (glucometer) can be a useful way to see if blood sugar falls at certain times of the day or after certain activities, such as after meals or after drinking alcohol.
If symptoms are more severe or persistent, however, then your doctor may recommend you fast for a specific length of time and monitor your blood sugar during that time. At Mayo Clinic, we typically have people stay in the hospital and fast for 72 hours while we watch them closely. Blood sugars are checked frequently. If the blood sugar levels fall, additional blood tests and other evaluations are done to determine the underlying cause.
A variety of disorders can lead to hypoglycemia in people who do not have diabetes. The most worrisome is a very rare tumor called an insulinoma. These tumors usually originate in the pancreas and cause the body to make too much of the hormone insulin. That, in turn, leads to an abnormal drop in blood sugar.
Other conditions that may lead to hypoglycemia include disorders that cause hormone imbalances, such as problems with the adrenal glands. Liver failure can result in low blood sugar, too. Hypoglycemia can be a side effect of certain medications. It also may be the result of taking too high a dose of a diabetic medication like insulin, or taking these types of medicines when you do not need them.
If you have low blood sugar regularly and it causes symptoms, do not ignore it. Low blood sugar can be potentially life-threatening. When you have your condition evaluated, seek care from an endocrinologist because the conditions that lead to hypoglycemia typically require specialty care.
Keep in mind, too, that hypoglycemia is not a condition on its own. It is a sign of another medical problem. Successful treatment of low blood sugar depends on accurately identifying and addressing that underlying cause. — Bithika Thompson, M.D., Endocrinology, Mayo Clinic, Scottsdale, Ariz.