The Children's Hospital June 24, 2016.

Denver doctors say 11-month-old boy’s deadly heart condition was likely related to marijuana

An 11-month-old Colorado boy’s death from a heart condition was likely related to ingestion of marijuana, two Denver doctors have concluded, but the precise link remains unclear.

The boy’s death was first reported in a study published last year about kids’ emergency room visits following marijuana legalization. The boy, who was not identified in that study, arrived at the hospital unresponsive and with a rapid heart beat, and he later went into cardiac arrest and died. He had no known history of health problems.

The boy tested positive for THC, the psychoactive compound in marijuana. But, at the time, the researcher on the original study said he was unsure whether that was related to the boy’s death.

But, in a different case report published this year, two doctors from the Rocky Mountain Poison and Drug Center reveal more information about the boy’s death, while drawing a more direct line between his heart condition and the THC in his system.

“As of this writing, this is the first reported pediatric death associated with cannabis exposure,” the authors, Drs. Thomas Nappe and Christoper Hoyte, write in the case report. The report was published online in March in a journal connected to the Western Journal of Emergency Medicine.

Update: New details emerge in 11-month-old Colorado boy’s death linked to marijuana

Marijuana, though, was not the boy’s cause of death. Instead, the boy died from myocarditis — an inflammation of the heart muscle.

Previous studies have linked heart problems in young people to heavy cannabis use. There have been reports in Europe of adults who have died of heart conditions after using marijuana. But researchers are still unsure exactly how marijuana would cause heart problems.

In the new case report, the authors never refer to the boy’s death as an overdose, and many of the details surrounding the death are still murky.

For instance, the doctors noted that the boy had been living in a motel and that a parent had admitted to drug possession, including cannabis. But the doctors noted no report of the boy actually ingesting cannabis. They instead wrote that it was unlikely — given the level of THC in the boy’s system — that he had merely been exposed to marijuana in passing.

The doctors could not say how much marijuana the boy likely ingested. They also could not pinpoint when the ingestion occurred, giving only a probable time frame of two to six days prior to his death. Lastly, they added that inconsistent blood test results meant there was a slight chance that the myocarditis may have been developing silently prior to the marijuana ingestion.

But, after ruling out multiple other causes of myocarditis, the doctors concluded that marijuana was the most likely cause of the heart condition. That finding, they argued, should be a warning to both doctors and to parents.

“In states where cannabis is legalized,” they wrote in the case report, “it is important that physicians not only counsel parents on preventing exposure to cannabis, but to also consider cannabis toxicity in unexplained pediatric myocarditis and cardiac deaths.”