My son has had type 1 for six years so we have seen some highs and lows, some extreme. In the last two weeks, his blood sugar level dropped once to 50 mg/dl [2.8 mmol/L] and another time to 58 mg/dl [3.2 mmol/L], which is the one and only time he went into a seizure. Why would this happen when he’s been lower than 58 mg/dl [3.2 mmol/L] and not seized?

The blood sugar level is only an approximation of brain glucose and often there could be a 30 to 45 minute time difference in brain versus peripheral blood levels. So, I would assume the levels were lower previously and, specifically, those in the brain likely lower. That would explain why lower previous values did not cause the same problem. Also, it would depend upon whether or not he had any alcohol in his system as is sometimes the case with some adolescents (you did give his exact age), excess activity, lack of appropriate prior food and/or insulin dosing errors (i.e., accidentally double dosing, other dose errors such as mixing up different types of insulins, etc.) as the cause.

SB