As the Canadian government prepares to legalize pot this summer, concerns are growing about a condition that often goes undiagnosed or is misdiagnosed — cannabanoid hyperemesis syndrome (CHS).CHS can often be a side effect of prolonged and heavy marijuana use, causing severe vomiting and abdominal pain.“As cannabis use becomes more prevalent and more chronic we are likely to see more cases over time,” says Dr. Glen Bandiera, chief of emergency medicine at St. Michael’s Hospital, Toronto.“It is a concern because people are quite uncomfortable with it and they can get quite sick with it, with fluid imbalances and dehydration. So it is something that needs to be recognized, it does require medical attention,” he says.Bandiera says they see about three or four cases of CHS in the emergency room every month, but there could be more cases that aren’t recognized as CHS because people are unfamiliar with the causes and symptoms. He says it’s important to raise awareness that CHS can result from chronic marijuana use.Former dispensary owner Jodie Emery is well versed in the effects of cannabis use and says the condition is paradoxical as people often use cannabis as a treatment for nausea, but insists that the health benefits outweigh any negative effects.In her experience, she’s heard of only one person who had a severe reaction, but it didn’t happen after smoking pot.“A lot of people have said that eating edibles or doing extracts or shatter or ‘dabbing’ as it’s called — sometimes that can overload your cannabinoid receptors with too many cannabanoids and they have an adverse reaction,” says Emery. “But again, its such a small number of people and often symptoms go away within 12-24 hours of abstinence.”While cases of CHS may be rare, doctors in Colorado say the number of cases there have doubled since the state decriminalized marijuana in 2012.Dr. Kennon Heard, an emergency physician and medical toxicologist in Denver says his hospital saw a big spike in the number of cases following decriminalization. That number has stabilized to about 50 to 70 cases a year.Not much is known about the factors influencing the increase, but Heard believes increased availability as well as increased potency of the herb is a factor.25 years ago pot contained about 3.4 per cent THC — the principal psychoactive constituent of cannabis. Today it can be as high as 18.7 to 30 per cent.“In Colorado … I can look across the street literally and I’m looking at a marijuana dispensary as I’m driving home, so I can walk there everyday and buy more than enough marijuana to use it multiple times in a day,” says Heard. “Then you throw on top of that the THC content of the marijuana we’re seeing is much higher, it sort of makes sense that is why we’re probably seeing more (cases).”Heard says when he was training in emergency medicine, textbooks said that acute marijuana use does not lead to emergency department visits.“Now I can tell you in my practice, pretty much every shift, I expect to see at least one person that’s coming into the ER with some complication related to marijuana use,” he says.While he stresses that the negative effects or marijuana use are not comparable to those of alcohol, cocaine, opioids and other such substances, it’s important to recognize and raise awareness about them.“I think anyone who says that there are no public health consequences for marijuana legalization is not really looking at the information that’s out there,” he says.Echoing Dr. Bandiera’s concerns, Heard says a lack of awareness about CHS means both doctors and patients often do not recognize it, which can sometimes lead to more serious repercussions.“We’ve had a few patients that have … become so dehydrated, they’ve had kidney injury and actually required admission to the hospital,” he says. “The main thing that happens is they get these very extensive emergency department evaluations for this abdominal pain and vomiting. No cause is ever found.”Heard adds that not only are the patients miserable throughout the entire ordeal which is prolonged by repeated testing and multiple ER visits, but it leads to missed work and consequently lost wages as well.Doctors say the only treatment is to simply discontinue marijuana use. However research is limited and each individual reacts differently — some may see an improvement in their condition sooner than others. Similarly, some people might see a recurrence when they use marijuana again, while others may not.“Unfortunately we can’t even say for sure that if you go from being a heavy user to a light, occasional user that you’re not going to have (CHS),” says Heard. “All we can recommend is if you’re having these symptoms and it’s disruptive to your life, you really need to think about quitting.”Raising awareness of CHS is an important issue for doctors and they say it is essential to get medical attention if you or someone you know may be suffering from the condition.CHS does not naturally subside and requires attention in an urgent care environment for fluid and electrolyte balance. Most patients make a full recovery when treated properly.