Dr. Rezette Dent is having a tough shift. As an intern, it’s hard enough to remember the code to the lounge, the location of the secret computer that allows you to print prescriptions, and the name of the patient you’re talking to. But when you forget to pack snacks or lunch, everything gets worse.
Dr. Dent says she gets hypoglycemia and typically carries a granola bar to cure her flushed, sweaty, nauseous, headache-ridden episodes. She’s never been in the ED during an episode before today and had her fingerstick glucose checked at the height of her symptoms. It was 112mg/dL. Huh. She seems to think the machine is broken; an emergently purchased granola bar still cures her.
The machine was working just fine. Dr. Dent just hasn’t thought about AKA that much.
Bear with me here: Our intern isn’t a diabetic and is in all other respects perfectly healthy. She routinely complains of these symptoms when she hasn’t eaten. This shouldn’t shock us, starvation can do that. Except our doctor’s normal liver and pancreas don’t like the idea of delivering no sugar to the brain. Since she’s not chronically starving or malnourished (as some of our ill and alcoholic patients are), the organ response: break down glycogen, break down fat, generate glucose, generate ketones. How does it get done? Through the so-called counter-regulatory hormones: glucagon, epinephrine, norepinephrine, cortisol and growth hormone.
What this means is that by the time Dr. Dent is feeling terrible, her endocrine system has taken care of her brain and her serum glucose is already rising. Why does she feel terrible? It’s BECAUSE of those signaling hormones. Glucagon makes you nauseous, epinephrine gives you flushing and sweats, and norepinephrine clamps your peripheral circulation. (GH and cortisol effects are likely delayed. To be academic, you get adrenergic and cholinergic sx, but not the CNS sx of seizure/coma/death.)
So then WHY does eating cure you when your sugar is already 112?
INSULIN IS THE ANSWER. Yes, sugar in your mouth is the signal that you’re not starving any more!
Sugar turns on insulin. Insulin turns OFF all those terrible hormones and makes you feel better: no more ketones, no more catabolic pathway.
Your Alcoholic KetoAcidosis patient who can’t tolerate po? He’s got a smidgen of low bicarb and a sugar that can be anything. Typically it will be normal or a bit high, but if he’s a chronic drinker he may have no glycogen stores and it may even be low! In that case, you’re in luck, no one will need to prod you to give him glucose intravenously. BUT, when you have a post-binge patient with a normal sugar who keeps throwing up, notice his ketosis and mild acidosis and put him on D5 anyway. He’ll get better for the same reason Dr. Dent did.
Pinaki Mukherji, MD, FACEP, FAAEM
Program Director, Emergency Medicine, LIJ Medical Center
Dr. Mukherji is the Residency Director at LIJ Medical Center in New Hyde Park, NY. He spends most of his time explaining things to patients in a way that they can understand, and to residents in a way that they cannot. He has a passion for education and trying not to do things wrong.