August 22, 2003
Diagnosis and Symptoms
Question from Guntersville, Alabama, USA:
I'm a 17 year old male with cystic fibrosis who is in good health with excellent lung function, but for the past few years, I have had symptoms of hypoglycemia that have increasingly become burdensome. At first, I would get hungry and if I didn't eat for a while, I would start to feel hypoglycemic (like I was going to pass out, shaky, etc.). The symptoms have changed a bit over the last couple year, and now when I have symptoms several times per day (usually every two to three hours, occasionally less or more). I have to eat something with a lot of protein or I won't really feel any better. Now for the strange part. When I experience symptoms, my meter blood sugar is usually in the 90s mg/dl [5 mmol/L], sometimes it's in the 80s mg/dl [4.4 mmol/L], and I have never seen it below the mid 70s mg/dl [3.9 mmol/L]. In addition, the blood sugar level doesn't necessarily correlate to the severity of symptoms. I can have terrible symptoms at 94 mg/dl [5.2 mmol/L] or I can have mild symptoms at 80 mg/dl [4.4 mmol/L] When I test my blood sugar (usually when I have symptoms, then an hour and two hours after I eat), it is not abnormally high, and I haven't had any other symptoms of CF-related diabetes. I'm not on any medications that would affect my blood sugar levels, and this is a problem every single day, not just now and again. It's also worth noting that what I eat (or how much) doesn't seem to have much of an effect on symptoms, for the most part. My symptoms vary a bit, but usually are: feeling faint, shaky (actually shaking a bit if it's really bad), hungry, quick pulse, anxious sometimes feeling dizzy, hot, nauseated, and they go away when I eat a small meal with adequate protein. If the symptoms are severe, they will lessen, and I'll feel like I'm not getting worse, but it may take some time after I eat to feel completely better. I have talked with my primary CF doctor, my pediatrician, and my CF dietitian about this problem. They all said pretty much the same thing -- that it's not hypoglycemia since my blood sugar is well within normal range. It's not dangerous, and they can't think of what would explain the symptoms. What might this be? What can be done about it? Could it possibly be panic attacks? I know they have some similar symptoms in common, but that just doesn't quite make sense.
Anxiety attacks produce all the same symptoms that you discuss.It could be hypoglycemia except, as you were advised, if you are doing the blood glucose readings correctly and never get a low blood glucose readings then this cannot be hypoglycemia, by definition. If this happens so regularly, then it may be worthwhile to stay around the office/clinic for several hours and when these symptoms occur, have them witnessed by your medical care team first hand.
Also, there is a condition where the body makes excessive adrenalin and other similar hormones. This is not related to cystic fibrosis or its complications to the best of my knowledge, however, and it is quite rare. Collecting special 24 hour urine samples are necessary for making such a diagnosis with consultation with an endocrinologist.
Finally, this does not sound like high sugars (diabetes).