Syndrome Linked To Smoking Weed Spikes In States With Legalized Marijuana

Robert Glatter, MD

On a recent shift in the ER, after multiple rounds of medicine to control his nausea, vomiting and abdominal pain, a patient explained to me that he had been smoking marijuana daily over the past 5-10 years. He also stated that he would often take hot showers and baths to help control his symptoms.

At this point--after describing how hot showers relieved his symptoms--it was clear to me that he was suffering from a poorly understood condition that some long term heavy pot smokers experience, now known as cannabinoid hyperemesis syndrome or CHS.

A recent CBS piece by Dr. Jon LaPook also shed light on this poorly understood condition in which patients develop patterns of cyclical vomiting and abdominal pain, often using hot baths and showers to control symptoms.

A man smoking marijuana  (CHRIS ROUSSAKIS/AFP/Getty Images)

But an interesting sidenote to this story is the increased prevalence of this syndrome in one state that  recently legalized the use of marijuana.

In his segment, he interviewed Dr. Kennon Heard who described his 2015 study from the Annals of Emergency Medicine which noted that, after medical marijuana was legalized in 2009, the prevalence of cyclical vomiting associated with cannabis doubled in two Colorado hospitals.  Colorado made recreational marijuana legal in 2012.

In states where marijuana is not legal, some healthcare providers may not be familiar with the presenting symptoms of CHS and associated use of marijuana. And rightfully so, some providers may neglect to ask if patients are using cannabis, with many patients unwilling to admit they are using an illegal substance.

The study also shows that with the doubling of the incidence of CHS, the propensity to self-report also increased significantly, better allowing healthcare providers identify such patients who may have repeated ER visits. The fear of reporting marijuana use by patients before legalization is certainly a limitation of the study, and may have led to overestimation of the increase seen in CHS visits.

Although CHS was first described in 2004 in Australia, there is little data on its incidence and prevalence. Since 2004, 31 cases were reported in the medial literature by Sullivan and colleagues in a 2010 report in the Canadian Journal of Gastroenterology.  With prolonged vomiting, there is risk for dehydration and ensuing kidney failure , unless intravenous fluids and antiemetics are administered. Most people who are treated with intravenous fluids do well, and the vomiting resolves within a few days.

A large percentage of patients who present to the ER with patterns of cyclical vomiting often undergo advanced imaging including abdominal ultrasounds and CT scans to rule out important pathology such as appendicitis, bowel obstructions, or inflammatory bowel diseases. MRI imaging to evaluate for central nervous system pathology is also common in this setting. The medical workup often is tailored to exclude metabolic and endocrine causes after a careful history and physical examination.

Another similar entity known as cyclical vomiting syndrome or CVS, is seen among patients with depression and migraine headaches, and should be part of the differential diagnosis. But when a patient reveals that they compulsively take hot showers in the setting of long term use of cannabinoids, CHS is the likely culprit.

While previous research has suggested that the anti-nausea effect of cannabis is achieved by its principal psychoactive ingredient, delta-9-THC, research has yet to undercover the rationale of how this compound can then paradoxically lead to its exact opposite effect— intense vomiting.

One theory proposes that a buildup of cannabis’ toxic metabolites in the brain leads to down regulation of the CB1 receptor, which then results in paradoxical enhancement of the compound’s intended effect.

A newer and more popular theory is that it's the concentration of cannabidiol in marijuana--as opposed to the psychoactive component delta-9-THC--that explains the proemetic effect in CHS. Animal models have demonstrated that cannbidiol is antiemetic in low doses but leads to vomiting at higher doses.

That said, the exact mechanism behind CHS is still not completely understood , but research so far has demonstrated that chronic marijuana use stimulates cannabinoid receptor type 1 (CB1) in the brain which results in reduced contraction of smooth muscle in the wall of the intestines. Researchers believe that because CB1 is situated closer to the so-called thermoregulatory center in the hypothalamus, the continuous hypothalamic stimulation of CB1 might be relieved by showering with hot water. 

Another theory involves the concept known as “cutaneous steal syndrome” in which hot showers help ease symptoms by drawing blood flow away from the gut, since chronic cannabinoid use results in CB1 induced vasodilation.