April 29, 2001
Diagnosis and Symptoms
Question from Kentucky, USA:
I am a 27 year old female who was diagnosed with hypoglycemia about three years ago. I was having the following symptoms: feeling faint, nauseated, sweating (beginning on the upper lip), dizzy, weak, blurred vision, nervousness in arms and legs, and not thinking clearly. I went to the doctor for an oral glucose tolerance test, and at some point, I dropped to 42 42 mg/dl [2.3 mmol/L]. The doctor reported that I most likely had hypoglycemia, but that it was really not that uncommon for a person to drop that low after this type of test. He said that I did not have diabetes.
I have had these same symptoms many times since and usually feel better once I eat something. I test my glucose level when I am feeling symptoms and most always am in the 70s mg/dl [3.9 mmol/L] in the morning and before I eat. Recently, I had these symptoms before eating, and after eating, I did not feel better. My test showed my glucose level to be 221 mg/dl [12.3 mmol/L] at 30 minutes after eating. I was extremely thirsty with frequent urination and blurred vision. (I had felt similar the day before, but did not have my machine with me to test.) I am usually so low that this alarmed me. I had not eaten sweets either. Two hours later, I dropped back to 113 mg/dl [6.3 mmol/L] and then woke up with symptoms again at 400 A.M. and my glucose level was 72 mg/dl [4 mmol/L]. After this, I have been checking my levels after eating and have been only in the upper 80s to low 90s mg/dl [4.4-5 mmol/L] 30 minutes to two hours after eating. Should I be concerned about this high glucose test and then low’s after eating at other times, or is this quite normal? I am not overweight and diabetes does run in my family (grandparents and uncle have been diagnosed).
Answer:
Your question is a good one. It is frequently asked by our patients. The most common type of hypoglycemia is termed reactive hypoglycemia. This is because the blood sugar falls excessively after meals. It is almost as if there is a slow braking mechanism on the amount of insulin secreted in response to a glucose challenge. As you might expect, the most common times to have symptoms include the period of time after meals. I think your physician is correct in underplaying the results of the oral glucose challenge test. A sugar of 42 mg/dl [2.3 mmol/L] is neither necessary or sufficient for a diagnosis.
The good news is that the glucose tolerance test was normal, and you don’t have diabetes. However, some people feel that these episodes of reactive hypoglycemia may be a forerunner of type�2 diabetes as it implies a form of hyperinsulinemia. This latter concept is not well worked out nor documented.
Another type of hypoglycemia is termed fasting hypoglycemia. This is where the sugar can get low at any time of day, regardless of the meal schedule. If the low symptoms are waking you up from sleep, that is different than a pattern that is predominantly after meals. It is in these patients that I will screen for an insulinoma, a tumor which autonomously secretes insulin.
You probably should have a fasting insulin and glucose level. In addition, if the symptoms keep waking you up, you should consider being admitted to the hospital where you will be asked to fast until you have symptoms and appropriate blood tests can be taken on demand. In the meantime, you need to concentrate on a healthy lifestyle. Try not to eat a large amount of simple sugars (cakes, pies, desserts), keep your weight down, exercise regularly, and speak with your physician.
JTL
