March 13, 2007
Diagnosis and Symptoms
Question from Chilton, Wisconsin, USA:
My four-year-old daughter is underweight and has had significantly high postprandial numbers over the last four months. We are monitoring with a home meter and the highs are intermittent. Some days, her blood sugar levels appear normal, while other days, she has very high spikes, 180 mg/dl [10.0 mmol/L] to 280 mg/dl [15.6 mmol/L], one to two hours after a meal. I have found no rhyme or reason to these numbers and it does not seem to matter what she eats. She also has intermittent symptoms like dizziness, blurry vision, thirst, yeast infections, etc. These symptoms seem to come and go. She also has had trace ketones in her urine on occasion.
Today, she had an oral glucose tolerance test. Her fasting number was 87 mg/dl [4.8 mmol/L] and after two hours it was 88 mg/dl [4.9 mmol/L]. Is this test definitive? We practice good procedures before doing finger prick tests at home like washing hands beforehand, etc., but doesn’t this test seem to rule out diabetes? Does this mean that her other high numbers at home are just an aberration? Can emerging diabetes show itself only on an intermittent basis? Could she “pass” this test and still be at risk for diabetes based on the intermittent numbers?
Answer:
The oral glucose tolerance test is mostly used for research purposes. The way you reported the test makes it impossible to comment because one would have to do 15 minute samples for the first hour and then half hour samples for a full two to three hours and usually with concomitant insulin levels as well. You are also correct that one can have intermittent abnormalities of the beta cells in the pancreas, especially in early phases of the development of diabetes and so, this would show up randomly on random blood glucose testing. The highs could perhaps occur with stressful days, days of illness or just when the pancreas was not “behaving” so well. Specific antibody tests would help, but only if positive and thus confirming islet cell inflammatory changes; negative tests are not so helpful and occur in up to 20% of instances. Genetic tests would also place an individual in high or low risk categories but are usually only available in specific research studies. If you still have concerns, you should discuss this with a pediatric endocrinologist with experience in such early detection of diabetes and not a general practitioner or general pediatrician.
SB
