A father from the Netherlands recently wrote to me about his son. I thank him for his question. He asked me a few very specific questions. I am reproducing them here as I feel it shall aid other people. My response to his questions follows. Names have been removed to maintain privacy.
My son is diabetic type 1, since his 5th year. And he had several seizures in the last 5 years. Mostly once a year, every time he had a hypoglycaemia.
The last time he had a epileptic seizure, with a fracture of thoracic vertebra 2. I have made a MRI scan of the brains, but everything seems normal.
Are there other investigations necessary to be sure it is an epileptic insult due to hypoglycaemia, instead of real epilepsy
thank you for writing in to me. If I get you right you are saying that all of your son’s seizures have occured in the setting of hypoglycemia. Do you by any change recall what was his blood sugar during these ictal episodes. For a seizure to occur due to hypoglycemia, the blood sugar has to usually fall down to an extremely low level (we call this neurohypoglycemia). As you are aware the brain needs sugar for energy and its metabolism so when blood sugar falls down to the range of 60 mg/dl or less, that is when a seizure occurs. The seizure in the setting of hypoglycemia is usually a generalized convulsion. That said I and many other physicians have seen patients presenting to the ER with focal findings suggestive of a stroke only to find them completely reverse once the blood sugar was corrected.
I do have a few practical suggestions for you:
–have a home blood glucose meter and check your son’s blood sugar at various times during the day such as in the early morning when he wakes up (fasting blood sugar), prior and after lunch (post prandial blood sugar) and finally before he heads to bed during the night. Do this for about 2 weeks and keep a record of the values in a notebook. This shall prove to be tremendously helpful to you as a parent and his physician to see how his blood sugar fluctuates during the day. Are there times when his blood sugar falls down/ bottoms out unexpectedly.
–a seizure due to hypoglycemia is rapidly reversible and in fact can be aborted with intravenous dextrose solution. Now it may be hard to administer intravenous dextrose at home.
–another very important point which comes to mind is why is he having so frequent hypoglycemic episodes. This shall require a thorough review by his endocrinologist. His insulin dose may need to be adjusted and/or he may warrant frequent small meals during the day to prevent his sugar from suddenly dropping.
–now to your final question: does your son actually have underlying epilepsy per-se. The answer to that depends upon this:
-has he ever had a seizure in the setting of normal glucose level?
-an EEG study shall be extremely useful. If the electroencephalogram shows inter-ictal epileptiform activity then likely your son does suffer from epilepsy. Remember in patients with seizures due to hypoglycemia per-se, the EEG between the seizures should be normal.
-a routine EEG (30 minutes study) can fail to reveal an answer. In that case a long term EEG monitoring study (24-72 hours either in the hospital or in an outpatient setting) may aid in characterization of his typical events.
-as you may have guessed right, patients with seizures due to hypoglycemia per se do not need to be on anti-convulsant therapy. In these patients what we need to ensure that they do not become hypoglycemic. No hypoglycemia means no seizures. On the other hand if your son does have underlying epilepsy, he shall warrant anti-convulsant therapy.
-also a neuroimaging study (ideally MRI of the brain) may he helpful to rule out any intracerebral structural cause of seizure.
I hope you find this information helpful. Please feel free to contact me again.
Nitin Sethi, MD