In a previous post, I provided an overview of diabetes. Everyone knows about diabetes, and most understand how dangerous diabetes is over the long-term. However, as an emergency physician, I’m more concerned with what will kill you immediately, and on that front, low blood glucose (sugar) is usually much more concerning. I want you to know up front that a low enough blood glucose will kill you – now. As we say in the ER, a high glucose level will hurt you and may kill you, but a glucose level that goes to zero means ‘Cancel Christmas’.
Therefore I will start with a simple statement. Any diabetic (or individual known to have low glucose levels) with altered mental status needs to be given juice or if they can handle it, some soft food to chew on. If they’re in the midst of a high sugar reaction, it won’t make much of a difference, but if that glucose level was zero, you’ve just saved a life. Now let’s briefly discuss symptoms and causes.

Low glucose levels can present many different ways including dizziness, jitteriness, numbness, tingling, blackouts, seizures and other symptoms. However, it’s usually the confusion or other change in mental status that’s most predominant and concerning. Just remember, this is not something about which you should wait around to see if it gets better.
Regarding causes, unintentional overdosing of insulin or oral medication (particular the sulfonylureas class of medicines) are especially concerning and common. Sometimes a family member, particularly a child, may take such a medicine to disastrous effects. Beyond that, heavy alcohol consumption on an empty stomach is another common cause due to its effects on the liver (Alcohol locks glucose stores in the liver, preventing release to the blood; as a result you have less to use.).
Other causes are more exotic and fortunately less common; they will be evaluated upon arrival to the hospital when a rapid response isn’t seen with simple administration of glucose. Dysfunction of certain organs (the adrenal and pituitary glands, the liver due to hepatitis, or tumors of the pancreas – the organ that produces the insulin that drives glucose into your cells – can cause problems with regulating either glucose itself or insulin. These conditions can drive your blood glucose dangerously low.
So, the causes are varied, but the message is simple. Be careful with insulin administration, remember to check those blood sugar levels and act promptly in the face of mental status changes. Usually I note that time is tissue, but in this example, you’ll run out of time before your tissues are damaged.