One Pill Can Kill: Marijuana Poisoning

Welcome to the latest One Pill Can Kill, a column about pediatric toxicology.

It’s 19:01, and you’ve just finished your walk-around and signed out your narc kit for the night shift when the tones go off. You set off lights-and-siren for a 2-year-old girl unable to wake up. Dispatch adds she is breathing and not blue. En route you consider a differential diagnosis for the unconscious child.

Let’s pause: What’s your schema for the undifferentiated unconscious child? Here’s mine:

Structural causes: blood, clot, pus, fluid, mass.

Structural causes are usually related to trauma or rare “zebra” diagnoses in children, like brain tumor, abscess, hydrocephalus, and pediatric stroke. I think of the 17-year-old who recently presented unconscious and was found to have a basilar artery occlusion.

Metabolic: AEIOU-TIPS

We’ve all seen this mnemonic in textbooks and PowerPoint presentations. Here’s my version of AEIOU-TIPS, which is not exhaustive but covers things I need to catch and have the ability to treat:

• A—Alcohol and drugs. This is at the top, and first on my mind is toxicology.
• E—Endocrine. Considering congenital adrenal hyperplasia in babies and other endocrinopathies could lead to quick delivery of steroids in the ER.
• I—Insulin and glucose. A quick stick for glucose will rule out hypoglycemia, and considering new presentations of diabetic ketoacidosis is pertinent in all altered children, especially those with tachypnea and abdominal pain.
• O—Oxygen deficit. Hypoxemia and hypoperfusion will be quickly discerned with your physical exam—cold extremities, cyanosis, and mottling—and of course your handy pulse oximeter.
• U—Uremia. This is much less likely in a child than an adult but may occur in babies with inborn errors of metabolism.
• T—Temperature extremes. Self-explanatory!
• I—Infections. Herpes simplex encephalitis and bacterial meningitis should always come to mind when assessing altered little ones.
• P—Psychiatric. This is a diagnosis of exclusion.
• S—Seizure/postictal. Perhaps unwitnessed, the resolved seizure may simply present as a post-ictal state. Fortunately for the diagnostician, these children usually tend to rouse within minutes.

Back to the Case

You arrive at a detached house and enter to find two worried parents on the phone with your dispatcher. A young girl lies on a couch with a blanket on her. Your pediatric triangle assessment is reassuring: Her color is good, her work of breathing is not increased, and when you pinch her trapezius, she localizes with her arms and moans. Your partner checks her glucose; it’s normal. Vitals are HR 122 sinus, RR 20 with clear air entry, BP 70/40, saturation 100% on room air. She has cool extremities with a cap refill of 4 seconds. You find no evidence of trauma, and the exam is otherwise noncontributory.

Recognizing the child is hypotensive and peripherally hypoperfused, you start an IV and initiate a 20-mL/kg bolus of normal saline.

The parents readily admit they fear their daughter ate one or two of their homemade brownies containing cannabis. Satisfied this is marijuana poisoning, you load the child into the rig and begin the 20-minute drive to the pediatric hospital downtown.

Cannabis Poisoning

Most paramedics have treated adults impaired by marijuana—whether because they crashed their car, thought they were having a heart attack, or mixed their weed with other drugs. But pediatric poisonings are on the rise as potent edibles become more common. Often in the form of brownies or gummy candies—both staples of my childhood—marijuana edibles can be potent for small children, who may eat more than even an adult dose by mistaking the drugs for regular candy.

Delta-9-tetrahydrocannabinol, or THC, is the psychoactive substance in marijuana responsible for most symptoms seen after its use. The potency of THC has increased over the years, and the actual dose of THC in homemade foods is difficult to know. When consumed orally THC can affect the brain for longer than inhaled forms. THC affects cannabinoid receptors in the central nervous system, which can affect GABA, an inhibitory neurotransmitter, and dopamine, which affects movement.¹ Symptoms of toxicity include decreased level of consciousness, wobbly walking, and respiratory depression.

While most adults who call 9-1-1 for help will know they’ve consumed a product containing THC, children who accidentally consume marijuana might not. Have a high index of suspicion for unwitnessed ingestion and ask if children had access to any edibles.

Case Conclusion

The child remains vitally stable and breathing for the duration of the transport. You notice a few twitches—nothing close to a seizure, but something you note every five minutes or so. You offload to a resus bed, where the ER doc decides to monitor the child. After completing your paperwork and grabbing a coffee, you pop back in and see your little patient is now sitting up in her mom’s lap, drowsy but awake. “I’m so sorry. I can’t believe I let this happen,” the mom says to you with tears in her eyes. “Accidents happen,” you reply.

A Word on Pediatric Poisoning

Accidents don’t happen in poisoning. Every time a child is poisoned, prevention failed. I prefer the term incident to accident.² As paramedics we have a responsibly to advocate for young patients who are poisoned to build better safeguards and prevent these incidents.

A lack of regulations for child-resistant packaging is partly to blame for the increase in pediatric poisonings called in to poison control lines across North America. Cannabis should be treated like any other medication or household toxin: locked up and out of reach of children.

Teens are also a group to watch. In Colorado, which legalized medical marijuana in 2010 and recreational marijuana in 2014, surveys show only 7% of teens used marijuana in 2015, the same rate as before it was legal, but cannabis-related emergency-room visits by adolescents quadrupled to 639 between 2009 and 2014, meaning five of every 1,000 emergency visits were associated with marijuana. The number of children under age 10 with unintentional cannabis poisoning went from one in 2009 to 16 in 2015.

Finally, an August study in the journal Pediatrics found THC in human breast milk at significant concentrations.³ Other studies have shown THC is found in the stool of breastfeeding infants whose mothers consume cannabis, suggesting babies metabolize THC, which has been shown to delay psychomotor development. Breastfeeding mothers should refrain from using cannabis.

References

1. Prabhu E. Pediatric Marijuana Exposures. American College of Emergency Physicians, www.acep.org/how-we-serve/sections/toxicology/news/march-2016/pediatric-marijuana-exposures/.

2. Bigham BL, Harding A, Goldfrank LR. Unintentional use of the word “accident”? Letter to the Editor, Clinical Toxicology, 2018 Jul 13; http://blairbigham.com/?p=1072.

3. Bertrand KA, Hanan NJ, Honerkamp-Smith G, et al. Marijuana Use by Breastfeeding Mothers and Cannabinoid Concentrations in Breast Milk. Pediatrics, 2018 Sep; 142(3): e20181076.

After a decade working as a helicopter paramedic, Blair Bigham, MD, MSc, EMT-P, completed medical school in Ontario, Canada, where he is now a resident physician in the emergency department. He has authored over 30 scientific articles, led major national projects to advance prehospital research and participated in multiple collaboratives, including the Resuscitation Outcomes Consortium.