One Pill Can Kill: The Case of The Insulin Insult
The Case
You’ve just cleared the hospital and hoping to make it to your favorite shawarma joint when your dispatcher calls your unit. A teenager locked himself in his bedroom and texted his mother a suicide note. Police arrived, broke down the bedroom door, found him unresponsive, and called for EMS backup.
Dispatch calls you a few minutes later; the police have learned the child has Type 1 diabetes and self-administers insulin. They’ve added up the empty vials and determined he’s probably injected three 10mL vials of insulin glargine (long-acting, 3000 units total) and two 3mL vials of insulin lispro (fast acting, 600 units total).
You arrive to find a teenage boy diaphoretic and comatose, with no signs of trauma. Other than empty insulin vials and syringes, no other drug paraphernalia was found. This isn’t much of a diagnostic dilemma; you stick his finger with a lancet, and your glucometer reads LO.
Insulin Overdose
Most insulin overdoses outside of hospitals (where iatrogenic overdoses are sadly an ever-present risk) are subcutaneous, which is important to note because subcutaneous absorption can be uneven and unpredictable, especially in overdose. Sometimes, patients will inject closer to a small blood vessel and absorb quicker; other times, they may be cold and have poor blood flow to peripheral fatty areas of their stomach and absorb more slowly. Hypoglycemia can last for days. This isn’t one of those cases where you give some dextrose and sign off.
Most insulin overdoses are unintentional and can often be managed with oral carbohydrates like orange juice or cookies but may require prolonged monitoring for rebound hypoglycemia if the insulin is long-acting. Yet intentional overdoses can involve a 10-fold or 100-fold overdose rather than a few extra units, posing a much greater risk—and much longer period of susceptibility to hypoglycemia. Because insulin also transports potassium intracellularly, hypokalemia is another risk and requires hospital monitoring.
Medical directives for glucagon, dextrose boluses, and dextrose infusions are a good place to start, along with frequent glucose checks. Repeat dosing or dextrose infusions (usually 10% will do) may be required. This is a good time to pull out a drug calculator or reference book, have your partner double check your drug math, and speak to your online medical control. But remember—unlike insulin, dextrose isn’t a drug that tends to kill people.
Back to the Case
By the time you arrive at the hospital 25 minutes later, you’re infusing 200cc/hour of D10 0.9% saline that you’ve mixed up, and you’ve given two additional boluses of D50W 25g IV. Your glucose is reading 5.9 mmol/L (106 mg/dL) and you take the liberty of giving one more bolus; you anticipate it to drop further, and don’t want the patient to have unrecognized hypoglycemia during triage and handover.
Acetaminophen levels are checked and are negative, excluding co-ingestion. The patient is admitted to the hospital under the pediatric service, where an octreotide infusion is added to his dextrose infusion at the advice of the poison control toxicologist. He receives a psychiatry consult the next day. He is weaned off the dextrose infusion and his glucose levels are stable on the third day of admission. He is transferred from medicine to youth mental health and is discharged five days after your encounter.
Citation:
https://pmc.ncbi.nlm.nih.gov/articles/PMC2556768/
Blair Bigham worked for a decade as a flight paramedic on four continents, a job he misses every day. He is now an ER and ICU physician at the University of Toronto and a public health researcher at the Dalla Lana School of Public Health. @BlairBigham blairbigham.com
