The US Drug Enforcement Administration plainly reports that no death from an overdose of marijuana has ever been reported—a tidbit often repeated by cannabis enthusiasts when discussing the potential harms of the popular drug. But this week, many news outlets coughed up headlines saying that the famous fact had gone up in smoke.
Those media reports dubbed the death of an 11-month-old Colorado boy as the first marijuana overdose death ever reported. They based that startling stat on a case report published in the August edition of Clinical Practice and Cases in Emergency Medicine.
But that’s not what the case report said—at all. And the doctors behind the report (who likely spent the week with their palms on their faces) are trying to set the record straight.
“We are absolutely not saying that marijuana killed that child,” one of the authors, Thomas Nappe, told The Washington Post Friday. Nappe, who is now the director of medical toxicology at St. Luke’s University Health Network in Bethlehem, Pennsylvania, cowrote the case report with Christopher O. Hoyte, an emergency medicine professor at the University of Colorado-Denver Anschutz Medical Campus.
In their case report, Nappe and Hoyte discuss the circumstances of the boy’s death, which was “associated” with cannabis exposure—not “caused by.”
The boy had suffered a seizure at home and arrived at the emergency department with slowed heart beat and breath. He subsequently went into cardiac arrest and died. In the 48 hours prior, the otherwise healthy, well-nourished boy had been lethargic, retching, and irritable.
The boy underwent a battery of tests and post-mortem exams. A urine toxicology test revealed the presence of tetrahydrocannabinol-carboxylic acid (THC-COOH), a metabolite of marijuana’s main psychoactive component, THC. Post-mortem blood draws from his heart confirmed the presence of marijuana compounds. Also, a single blood draw from a jugular vein revealed the presence of Bacillus bacteria.
Last, an autopsy revealed that his heart was severely inflamed, a condition called myocarditis. The type of tissue damage and immune response appeared consistent with drug-induced, toxic myocarditis rather than myocarditis caused by a bacterial or viral infection.
Together, the clinical tests “support a potential link between the cannabis exposure and myocarditis that would justify preventive parental counseling and consideration of urine drug screening in this reported setting,” the authors explained (emphasis added).
Further backing a potential link, the authors noted three separate case studies of otherwise healthy adolescents who suffered myocarditis associated with cannabis use. In all cases, there were no other explanations for the inflammation and no other drugs found in the patients. But “unlike our patient, all three of these previously reported patients recovered,” Nappe and Hoyte noted.
There is other data on cardiac effects of cannabis on adults as well as infants, including slowed heart rate. But there has never been a clear link to deadly myocarditis in infants before.
Based on all the test results and the metabolites present, the doctors speculated that the baby had eaten cannabis in the previous two to six days, with inflammation developing in that time. That’s assuming the baby had just one highly potent ingestion. The parents did not know the timing or route of the exposure, but the doctors noted “an unstable motel-living situation and parental admission of drug possession, including cannabis.”
With the potential link, the doctors called for more research, saying, “Given two rare occurrences with a clear temporal relationship—the recent exposure to cannabis and the myocarditis-associated cardiac arrest—we believe there exists a plausible relationship that justifies further research into cannabis-associated cardiotoxicity and related practice adjustments."
But plausible relationship and potential links don’t add up to cannabis causing the baby’s death. The doctors also flag the one blood test positive for Bacillus. They note that there’s a good chance it was positive due to contamination rather than a real result—it was the only positive sample out of many. But bacterial infections can contribute to, if not solely cause, inflammation as well. It remains undetermined what sparked the baby’s cardiac arrest.
Still, even if cannabis exposure was to blame in this case, such events appear rare. In a 2014 review of 985 inadvertent pediatric exposures to cannabis, cardiovascular symptoms occurred in less than two percent of cases, and myocarditis was not reported. Moreover, none of the children died.