Your next patient is a small five-year-old boy who is rather thin and pale. He is lying on the gurney and not responding to anything. On rapid assessment, his airway, breathing and circulation seem to be OK. He isn’t actively having a seizure. His mom says she brought him in because his blood sugar is low. You get a bedside glucose and she’s right, it’s 38. You start a line and grab a couple of tubes of blood before you start any dextrose. You bolus him with 5 ml/kg of 10% dextrose rapidly through the peripheral line. Now it’s time to talk to the mom and get more of the story.
She says he’s had this problem since he was two. He’ll have episodes of vomiting and become unresponsive and when he’s taken in to the ED his blood sugar will be low. He’s been admitted for this in the past but his work-up has been inconclusive. Mom says that she was to tell the ED the next time he came in to get some labs before they give him glucose. OK, now you’re feeling pretty good about those tubes you snagged.
This morning was a pretty typical episode for him. He woke up and began vomiting. No fevers. Mom gave him Zofran but he vomited that too. She kept checking his blood sugars and they ranged from 49-59. She made one more attempt to get him to take something by mouth but he threw that up too, so she loaded him in the car and brought him in to the ED. He’s vomited about 8 times. No diarrhea, no fevers, no ill contacts. His past history is otherwise unremarkable. He’s on no meds except Zofran as needed. No one in the family has any metabolic or endocrine disorders. There are no medications in the house except for antipyretics and his Zofran.
He begins to wake up and asks for a drink of water. His exam is nonfocal and he doesn’t look particularly dry. His bedside glucose is now 122. You slip some Zofran in his IV fluids and put him on D10NS at one and a half maintenance. He feels like he can pee so you send him down the hall and collect a urine sample.
So, what’s going on with this kid? What labs do you need and why is the timing so important? Shouldn’t they have done the big work-up that time he got admitted?
Hypoglycemia is defined as a plasma glucose of less than 50. If the child isn’t taking insulin for diabetes, hypoglycemia is usually due to inadequate intake (fasting), plus or minus increased demand (like gastroenteritis). The liver is the main player in maintaining adequate serum glucose. When oral intake is low, the liver first converts glycogen stores to glucose, then lipolysis occurs and fatty acids are broken down to produce energy and ketones. Gluconeogenesis involves the production of glucose from glycerol, lactate, and some amino acids. Insulin inhibits this process (it is anabolic) and cortisol, epinephrine, glucagon, and growth hormone promote it (they are catabolic).
While there are a number of reasons a child could be hypoglycemic, the most likely cause of this child’s repeated episodes is ketotic hypoglycemia. Children with ketotic hypoglycemia usually present as toddlers with lethargy or seizure following a prolonged fast. A typical scenario would be a youngster who was a bit ill or sleepy and skipped dinner, was put to bed and was unresponsive in the morning. For reasons that are unclear, these kids fail to mount an adequate response to the stress of fasting. They make ketones, indicating that some lipolysis is going on, but they cannot achieve adequate guconeogenesis. The emergency physician who confronts the lethargic child and documents the hypoglycemia, then provides dextrose and the problem resolves. Children with ketotic hypoglycemia tend to grow out of it by 3rd or 4th grade. Parents are instructed that the child should avoid fasting. They get a bedtime snack and if vomiting or refusing to eat, should get woken up during the night and offered snacks or glucose-containing fluids.
There are a few other entities that can look similar. Children who present for the first time with hypoglycemia should be admitted for a work-up and ketotic hypoglycemia should be a diagnosis of exclusion. As an EP you have a unique ability to make a diagnosis. Enzyme and hormone defects producing periodic hypoglycemia will have telltale lab results that may diminish or disappear within 15-20 minutes of dextrose administration. The Ward team, coming to the ED an hour later to admit the patient will not catch these diagnoses – that’s why grabbing a couple of red tops and refrigerating them initially is vital. These patients will not outgrow their tendency to hypoglycemia with metabolic stress. Every time they get hypoglycemic, they can take a neurologic hit, with the risk of brain damage. Send the blood for serum amino acids, acylcarnitine profile, insulin, cortisol and growth hormone levels. Can’t remember this – no problem. Get a couple of red tops, refrigerate them and then look it up at your leisure. The bottom line is to draw blood before correcting the hypoglycemia. Also get a urine. If the child is fasting and hypoglycemic, they ought to be producing serious amounts of ketones. If not, they have a disorder of lipid metabolism. Send urine for organic acids as well. If the history suggests it, remember to consider toxic ingestions, sepsis, reye syndrome and hypopituitarism as well.
This child got the metabolic labs sent from the ED before resuscitation with dextrose. They were nondiagnostic and he is considered to have ketotic hypoglycemia, which he should grow out of with time. In the meantime, mom knows to avoid fasting, pop in a Zofran if he is vomiting, and come in early if he is not taking adequate po.
Grab some tubes, then treat the sugar. You may be the only one who can make the diagnosis in a hypoglycemia kid. Most of them will come back negative, but you never know. Happy hunting.
There are a few kids out there who are prone to hypoglycemia. They may be diabetic and on insulin, or have ketotic hypoglycemia or metabolic disorders that cause them to drop their blood sugars with stress. One thing that mothers can do is stock up on cake frosting. It’s pretty much pure sugar and can be slapped on the tongue of a hypoglycemic child on the way to the ED. Tubes of decorator icing can be carried in a purse or diaper bag as well.
Amy Levine, MD, is an assistant professor of pediatric EM at UNC Chapel Hill