The U.S. House of Representatives passed the Marijuana Opportunity, Reinvestment, and Expungement (MORE) Act in December 2020 in a bipartisan 228-164 vote, removing it from the Controlled Substances Act and ending criminal penalties under federal law. This spring, three leading senators—Senate Majority Leader Chuck Schumer (D-NY), Senate Finance Committee Chairman Ron Wyden (D-OR), and Sen. Cory Booker (D-NJ)—were working on legislation that would do the same in the Senate.
Meanwhile, at least 17 states had passed laws legalizing or at least decriminalizing the use of Cannabis while another 16 (33 total) permitted the medical use of Cannabis, according to the National Cannabis Industry Association.
With Cannabis legalized in more and more states and possibly soon at the federal level, it is likely that emergency physicians will see an increase in emergency department visits related to its use. That's the experience Colorado emergency physicians have had over the past two decades as Cannabis use went from illegal before 2000 to becoming legal for medical reasons between 2000 and 2009 to fully legalized, regulated, and commercialized in 2014.
An article by emergency physician Brad Roberts, MD, at the University of New Mexico in Albuquerque, assessed trends in ED visits and hospitalizations with marijuana-related billing codes between 2002 and 2015 in Colorado using data provided by the Colorado Hospital Association. The state saw 575 hospitalizations with marijuana-related codes per 100,000 population and no ED visits in 2000 before medical marijuana was legalized. Between 2010 and 2013, the state had 1440 hospitalizations and 739 ED visits per 100,000 population; those numbers increased to 2413 hospitalizations and 956 ED visits per 100,000 population between 2014 and 2015. (West J Emerg Med. 2019;20:557; https://bit.ly/3fFVzaF.)
Findings reported by the University of Colorado School of Medicine in 2020 confirmed those results; the authors found that 4.36 of every 1000 ED visits in 2012 could at least partly be attributed to Cannabis. That number had jumped to 15.95 of every 1000 ED visits by 2016. (Clin Toxicol [Phila]. 2020;58:453.)
Besides providing an account of what happened in Colorado, they also offer a glimpse into what EDs can expect to see in the wake of increasing Cannabis legalization across the country.
Patients with Cannabis-related ED visits are more likely to be male: 43.5 percent of all ED patients were male and 56.5 percent were female while 62.6 percent of Cannabis-related visits involved men and 37.4 percent involved women, according to the University of Colorado study.
They also tend to be younger than your typical ED population, with a median age of 36 compared with 39, the same study found. In fact, research from investigators at the University of Nevada-Las Vegas actually identified adolescents and teens as the highest-risk age group for Cannabis-associated emergency department visits. “Children ages 12-17 had more than three times the risk of an ED visit related to Cannabis than the reference age group of 35-44,” said Jay Shen, PhD, an associate dean of the School of Public Health and a professor of Health Care Administration and Policy at the University of Nevada-Las Vegas. Young adults ages 18-24 had at least twice the risk of ED visits associated with Cannabis as the reference age group. (J Addict Med. 2019;13:193.)
Dr. Shen's study did not include pediatric admissions under age 12, but “pediatric accidental overdoses increased in Colorado after Cannabis was legalized,” said Sherry Yafai, MD, a Cannabis and emergency physician at Providence St. John's Medical Center in Santa Monica, CA, and the founder of the ReLeaf Institute.
A study from another group of researchers at the University of Colorado found that annual admissions at a children's hospital and regional poison center increased 1.2 per 100,000 population two years prior to legalization to 2.3 per 100,000 population two years after legalization (p=0.02). “Almost half of the patients seen in the children's hospital in the two years after legalization had exposures from recreational marijuana, suggesting that legalization did affect the incidence of exposures,” wrote lead author George Sam Wang, MD, an associate professor of pediatrics-emergency medicine at the University of Colorado School of Medicine. (JAMA Pediatr. 2016;170:e160971; https://bit.ly/3u8PybB.)
Dr. Shen's study found that adults over age 64 are at significantly reduced risk of Cannabis-related ED admissions compared with the reference age group, but that doesn't mean you won't see seniors in your ED with Cannabis-related conditions. “In the post-recreational situation, suddenly people who never would have explored the world of Cannabis are considering it, such as elderly people whose grandkids are encouraging them to use it while at the same time they are seeing direct-to-consumer advertising,” he said. “These are people who are often also on multiple medications, which can lead to a greater potential for bad outcomes.”
One significant risk for older adults associated with Cannabis use: accidental injury. A 2018 study from the University of Texas at Austin, which used data from the 2012-2013 National Epidemiologic Survey on Alcohol and Related Problems, found that 3.9 percent of the respondents 50 and older reported using marijuana in the past 12 months. Nearly 29 percent of them experienced an injury that required them to seek medical help or limit their usual activities for more than half a day, compared with 18.8 percent of nonusers (p<0.001). Older marijuana users also had higher rates of ED visits than nonusers (30.9% and 23.5%, respectively, p<0.001). (Am J Drug Alcohol Abuse. 2018;44:215; https://bit.ly/3ypxYnb.)
What EPs are likely to see in a Cannabis-related ED visit depends to some extent on whether the Cannabis use is one time—possibly accidental—or chronic. “When people accidentally ingest Cannabis and don't know what they've taken, they can often end up in the ED,” Dr. Yafai said. “In the elderly, you will have a presentation that mimics cerebellar stroke, which is something we've seen often in Los Angeles EDs. Symptoms will include dizziness, confusion, and word-finding difficulties.”
Differentiating Cannabis ingestion from a stroke in an elderly ED patient can be difficult, she said. “Unless you can get a urinary tox screen back in an appropriate time frame, which almost certainly won't happen, it ends up being a risk-benefit analysis as to whether you order tPA. But if a patient's MRI and other scans are all clear and it's just a little bit of confusion or haziness that comes and goes, that's more likely to be Cannabis-related. If there are diffusion differences, that's a good reason to go ahead with tPA.”
Another common ED presentation related to acute Cannabis toxicity involves some combination of panic and anxiety, tachycardia, nausea and vomiting, and hypertension or hypotension. “Sometimes they know what they've taken, and sometimes they don't,” Dr. Yafai said. “The treatment of choice in these patients is usually benzodiazepines, which most emergency physicians will use anyway. The typical patients with these symptoms include 20-somethings out to have a good time, a housekeeper or a babysitter who accidentally ate something in their employer's home, or an elderly person whose teenage grandchild or adult child gave them something or left it out. I had one patient whose adult son left a Rice Krispies treat laced with Cannabis in the front seat of his car, and then his father borrowed the car and ate the whole thing. We had no idea there was a toxin until the son showed up concerned his father had a stroke.”
The more concerning situations involve accidental ingestion by pediatric patients. “The biggest harm that we've seen here is that the ER community has had two case reports of children aged between about 5 and 7 who were bradycardic and hypotensive, with a brief cardiac pause that was too short for any intervention to be done and resolved on its own,” Dr. Yafai said. “They were admitted to the pediatric intensive care unit for a 24-48-hour stay and then were able to be discharged.”
Chronic Cannabis use that leads to an ED presentation is also commonly associated with mental health diagnoses (more than a threefold increased odds ratio, according to Dr. Shen's study) and other substance use (more than a 14-fold increased odds ratio). “In general, we can assume people with mental health issues tend to use more substances, including marijuana and other drugs such as opioids, as well as drinking alcohol and smoking cigarettes,” Dr. Shen said.
The University of Colorado study found that the largest single category of clinical complaints associated with Cannabis-related ED visits by far was psychiatric (24.8%). Nearly 19 percent of those patients came to the ED because of a suicide attempt. “Just 25 percent of the psychiatric complaints were chronic in nature, with most of these patients experiencing an acute exacerbation of a chronic mental health condition such as schizophrenia or depression,” the authors wrote.
The other most common accompanying diagnosis for chronic Cannabis use is gastrointestinal problems. Dr. Shen's study identified an increased odds ratio (1.155, p<0.01) for these conditions. “People presenting to the ED who have used Cannabis are also more likely to have gastrointestinal tract problems,” Dr. Shen said.
Other studies have also identified this association: A 2016 report from researchers at Beth Israel Deaconess Medical Center and Harvard Medical School found that the rate of ED visits for vomiting with Cannabis use disorder increased from 2.3 per 100,000 ED visits in 2006 to 13.3 per 100,000 visits in 2013. (J Clin Gastroenterol. 2018;52:778; https://bit.ly/3oEEa6b.)
Investigators at McMaster University in Hamilton, Ontario, Canada, also reviewed the records of all adults 18-55 presenting to the ED with vomiting and cyclical vomiting during a two-year period, and found that 19.4 percent of the 494 cases identified Cannabis use. Forty-three percent of regular Cannabis users (more than three times per week) also had repeat ED visits for similar complaints. (CJEM. 2018;20:550.)
The vast majority (85%) of gastrointestinal complaints associated with Cannabis-related ED visits in the University of Colorado study were due to repeated bouts of nausea and vomiting known as cannabinoid hyperemesis syndrome. At least two fatalities have been associated with the condition. (J Forensic Sci. 2018;64:270.) No single test can confirm it, but long-term weekly and daily marijuana use, belly pain, severe, repeat nausea and vomiting, and relief after taking a hot shower point toward the diagnosis.
“This becomes a ‘which came first’ question for the emergency physician,” said Dr. Yafai. “Did the patient have cyclic vomiting and start using Cannabis to help with it, or did he develop cyclic vomiting after regular Cannabis use? It may be hard to convince a 25-year-old that the Cannabis use is causing their vomiting when they've heard that it actually helps with nausea. But this is a good test: If a person has cyclic vomiting from anything else, a shower won't make it better.”
She noted that despite some evidence that Cannabis can be useful for severe hyperemesis gravidarum, emergency physicians must stay away from this recommendation if these patients present to the ED. “We cannot advise this use until the legal repercussions are removed,” Dr. Yafai said. “Could it be potentially beneficial as compared with Zofran or other prescriptions for hyperemesis? We don't know that, and we cannot recommend something that will jeopardize child custody, regardless of legality in a state.”
One thing you probably won't have to worry about as an ED presentation related to Cannabis legalization: upticks in violence. “You just don't see the violence associated with Cannabis that you see with drugs like cocaine and crack,” Dr. Yafai said. “And with legalization, we should also start to see less of the dangerous THC mimics and synthetics.”
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Ms. Shawis a freelance writer with more than 20 years of experience writing about health and medicine. She is also the author of Having Children After Cancer, the only guide for cancer survivors hoping to build their families after a cancer diagnosis. You can find her work atwww.writergina.com. Follow her on Twitter@writergina.