My four and a half-year-old son has been having several weeks of increased urination and thirst. A urine dipstick on a first morning urine revealed some glucose (50) without ketones. His fasting blood sugar was 75 mg/dl [4.2 mmol/L] and his A1c was 5.1. His doctor could not give an explanation for the sugar in the urine but felt like we had safely ruled out diabetes. However, I am to call if I see an increase in symptoms. Is diabetes safely ruled out at this point or do I need to monitor anything with him?

While the possibility of diabetes mellitus has not been entirely excluded, it has been nicely screened for and is probably not the cause of the symptoms and laboratory test you described.

How was the fasting glucose determined? Was it by a “fingerstick” with a portable glucose monitor? In the situation you describe, I probably would want a genuine venipuncture blood test. I might even want what I call a “poor man’s glucose tolerance test.” (This is NOT a true oral glucose tolerance test [OGTT], but is in the same ballpark for a lot less money.) Get the venipuncture blood test fasting at 8 a.m.. Then, go to your local pancake house (or at home) and have the child load up on a carbobohydrate-rich breakfast of juice, pancakes or waffles or french toast with syrup or jam, etc., chocolate milk, etc. At 10 a.m. (or two hours from when the first morsel of breakfast crossed his lips) do another venipuncture blood glucose test. If this two hour glucose level is also normal, I think you have given a real college try to demonstrate diabetes. Certainly, a formal, properly performed OGTT can be done, but these are often done incorrectly so I do not usually request primary care providers to perform them.

Other factors that come into play: is there a family history of diabetes or other autoimmune disease? Does the child receive medications? Is he growing and thriving otherwise?

There is another, essentially benign condition whereby the kidneys aren’t reabsorbing some sugar during urine processing. This sugar in the urine is “mistaken” for glucose during routine urine “dipstick” tests. There are other intrinsic and concerning kidney diseases that can lead to “spilling of glucose into the urine.” They are associated with normal blood glucose and thus are not diabetes related, but they can be associated with increased urination and thirst. Such issues may be assessed by a pediatric nephrologist (kidney specialist).

I think your pediatrician will want to follow up. Please let us know.

DS