June 7, 2008
Diagnosis and Symptoms, Other Illnesses
Question from Rock Hill, South Carolina, USA:
My now two-year-old son has had some concerning symptoms for which we have tried to find answers. He has Shwachman Diamond Syndrome (SDS), a bone marrow failure syndrome that effects the exocrine pancreas. Since his exocrine pancreas started to show major signs of failure, he started drinking up to 40 to 50 ounces of liquid a day and having extremely wet diapers. This seems to come and go (is not everyday). We started checking is sugar levels, which, for the most part, are in the normal range. At times, his fasting is around 110 mg/dl [6.1 mmol/L] and some two hour after meal blood sugars have been around 165 mg/dl [9.2 mmol/L]. Again, this is not all the time and not due to illness.
We took him to a pediatric endocrinologist right after we found out about the SDS and that doctor just said the drinking and peeing was from habit, that the A1c was 5.2 and, that day, his finger stick glucometer check was 111 mg/dl [6.2 mmol/L]. He basically told me that since he thought it was habit, my son wasn’t at risk for type 1 diabetes, and diabetes insipidus had already been ruled out. Furthermore, the doctor said that he had never heard of any exocrine issues causing endocrine issues except in cystic fibrosis. This was in January of this year.
We waited until this month to see if the symptoms would go away or subside; they have not. Our pediatrician ordered a one hour glucose test and a fasting insulin level. That day, my son had a fasting glucose (drawn from arm) of 93 mg/dl [5.2 mmol/L] (range of 65 mg/dl [3.6 mmol/L] to 105 mg/dl [5.8 mmol/L]) and then a one hour reading of 85 mg/dl [4.7 mmol/L] (range 120 mg/dl [6/7 mmol/L] to 170 [9.4 mmol/L]). After drinking the orange drink (about 3 ounces of the bottle since he weighs 26 pounds), he got very tired and tried to fall asleep.
Since I was not happy with just one test level and that it was flagged as low, I asked to have the three hour test done. There are days when he wakes from naps very agitated and shaky. And, we are coming up on a year of these symptoms.
The three hour test was ordered a week later and his fasting level was 100 mg/dl [5.6 mmol/L]. About 45 minutes later, they gave him about two ounces of the orange drink (would two ounces versus three make a difference?). At one hour, he was 116 mg/dl [6.4 mmolL] (again low); at two hours, he was 120 mg/dl [6.7 mmol/L]; and at three hours, he was 85 mg/dl [4.7 mmol/L]. At the three hour draw, he was visibly shaking and we had to keep waking him up. He started to get tired again after the liquid and falling asleep after the second draw. We had to make him walk the halls to stay awake.
The pediatrician called to tell me that all the levels were “normal.” What am I supposed to think with the one hour being VERY low out of range from the first testing and then his obvious sleepiness and tired shaking from the second testing? Is there something I should be doing at home to keep him more stable? Should we force the issue and go back to the pediatric endocrinologist? Or, should we just leave it all alone and watch him at home, but do nothing?
Answer:
Sorry, but pediatricians should not be ordering such tests. Your pediatric endocrinologist is correct that all these blood glucose levels are normal. The laboratory values must always be interpreted. However, the blood sugar of 165 mg/dl [9.2 mmol/L] is not normal. Some of your symptom descriptions suggest hypoglycemia, but this would only be diagnosed if there were a concomitant blood sugar below 60 mg/dl [3.3 mmol/L] during which time there also were symptoms. I also would agree with your pediatric endocrine consultation. Shwachman Diamond syndrome should not be associated with problems of the endocrine pancreas (i.e., whether too much or too little insulin). But, I do not have a good diagnosis. Under such circumstances, it would be prudent to do what we call a profile. Check his blood sugar levels at home before breakfast and then one hour after breakfast, before lunch and then one hour after lunch and before diner and then one hour after dinner. Plus, also check his blood sugar any time he is sluggish, cold, pasty-pale looking, shaky, with headaches or stomach aches. These could all be signals of hypoglycemia. If you never can document a blood sugar below 60 mg/dl [3.3 mmol/L], then the symptoms are not likely glucose related. Before meal blood sugar readings usually are in the 60 mg/dl [3.3 mmol/L] to 100 mg/dl [5.6 mmol/L] range and post-meal values are usually between 60 mg/dl [3.3 mmol/L] and 140 mg/dl [7.8 mmol/L]. If there were significant values below 60 mg/dl [3.3 mmol/L] and/or above 140 mg/dl [7.8 mmol/L], then I would suggest going back for a follow-up consultation with the pediatric endocrinologist to review these results and decide what further evaluations may be needed.
SB
