By Randolph Fillmore
A study conducted by researchers at Johns Hopkins All Children’s Hospital should serve as a “heads-up” to doctors who might see young patients in the emergency department who have a history of chronic nausea and vomiting. It is possible that their young patients are suffering from cannabis hyperemesis (CH), a condition related to long-term, frequent marijuana use.
“CH is an under-recognized condition for those who use marijuana and experience long-term and cyclic vomiting,” explains study lead author Hannah Lonsdale, MBChB, a research associate in the Johns Hopkins All Children’s Department of Anesthesia and Pain Management. “It was once considered rare but is being increasingly recognized in adults, adolescents and children.”
The researchers fear CH may become more common as decriminalization of cannabis in many U.S. states leads to its more widespread availability and use.
In addition to cyclic, chronic vomiting occurring after three months of regular cannabis use, symptoms of CH, also referred to as “cannabis hyperemesis syndrome,” or CHS, may also include abdominal cramping and obsessive relief of symptoms by prolonged bathing or showering in hot water.
Their study, titled “Pediatric Cannabinoid Hyperemesis: A Single Institution 10-Year Case Series,” was recently published in the Journal of Adolescent Health (No. 68, 2021). The study was noted by the journal’s editors to be “the largest case series in print on CHS” in adolescents and young adults.
Importantly, the researchers also raised the issue of revising the current criteria for diagnosing CH because their study has shown that so many cases are missed. The journal’s editorial accompanying the study, titled “The Coming Storm: Cannabis Hyperemesis Syndrome in Adolescents,” congratulated the authors for highlighting “two shortcomings of our current health systems,” referring to the findings that reveal the low frequency of diagnoses at first clinical encounters and that most CH patients were not referred to substance abuse counseling or psychiatric evaluation.
The journal editorial also suggested, as did the researchers, that the legalization of cannabis in many U.S. states could increase the frequency of CH.
CH or CVS?
In their paper, the researchers emphasized that clinicians seeing young people with chronic, cyclic vomiting should dig a little deeper into their patients’ histories to see if cannabis abuse could be a possible cause. Heightened awareness of CH will help clinicians distinguish between CH and cyclic vomiting syndrome (CVS), a condition with similar symptoms but unrelated to frequent and long-term cannabis use.
“Cannabis hyperemesis shares features with cyclic vomiting syndrome,” explains the study’s senior author, Michael Wilsey, M.D., who specializes in pediatric gastroenterology, hepatology and nutrition in the Johns Hopkins All Children’s Department of Medicine and is vice chair of the Division of Gastroenterology. “Many CH cases are not recognized at their first presentation because health care providers may be unaware of the condition and also don’t take a detailed history of drug usage from children and adolescents.”
Wilsey also suggests that clinicians should be more vigilant for the condition, take a detailed drug history when assessing adolescent patients with chronic vomiting, and refer younger patients to follow-up services to help prevent adolescent CH sufferers from becoming the adult CH patients of the future.
The study, a retrospective investigation going back 10 years, was conducted by reviewing electronic medical records (EMRs) of 34 patients, ages 13-20, with a median age of 17, who came to Johns Hopkins All Children’s with abdominal pain, nausea and chronic vomiting, and reported regular cannabis use. Many of the patients experienced weight loss and changes in bowel habits but had no other underlying medical conditions that could explain their symptoms.
Co-author Jerry Brown, a research collaborator associated with the Division of Gastroenterology, who carried out much of the data gathering and analysis, notes that patients with underlying medical conditions that could have caused their nausea and vomiting were excluded from the study.
“A detailed history of cannabis use – how long and how frequently it was used – was incompletely documented for a significant number of the patients,” explains Brown. “Frequency of use was available for 24 patients who used cannabis a median of 21 times per week.”
The retrospective study also found that few patients with regular cannabis use and diagnosed with CH were referred to drug abuse programs.
Revising CH Diagnostic Criteria
The editorial also agreed with the authors’ suggestion that new criteria should be developed for diagnosing CH because the previously developed diagnostic guidelines may not be useful. The researchers and the journal editors called for revising the pediatric diagnosis criteria for CH as developed by the Rome Foundation’s committee on gastroduodenal disorders and published in 2016 in Gastroenterology (150:1380–1392). The Rome criteria said only that CHS resolves with cessation of marijuana smoking and that CHS should be managed by withdrawal of marijuana, adding that “many patients are unwilling to follow this advice.”
“Using the 2016 Rome criteria, only three of the 34 patients in our case series would satisfy the Rome IV criteria for diagnosing CHS in adults,” Lonsdale says. “That suggests that these criteria are not useful for diagnosing CH in adolescents.”
Readers may be aware that cannabis has been used to ease nausea and prevent chronic vomiting in some patients, including those with chronic vomiting syndrome. But how is it that the same substance could work in two different ways?
According to the researchers, the contradiction of how cannabis can prevent nausea and vomiting in some conditions, yet cause it in others, is related to the poor understanding of the substance’s “pathophysiology.” They suggest that the repeated stimulation of both cannabinoid receptors, type 1 and type 2 (which we all have), may play a role in causing CH when those receptors may be “over exposed” and that there is a “down regulation” of the receptors with different effects with high or low doses of cannabis.
Only One “Cure” for CH
Because it is frequent and long-term cannabis use that sets CH and CVS apart, the only definitive relief from symptoms, added the researchers, is permanent cessation of cannabis use. However, the study found that few children diagnosed with the condition are being referred for substance abuse counselling or psychiatric evaluation. The study authors hope that their research and published study can raise the profile of this under-recognized condition and sound a loud “alarm” for clinicians who encounter young people with cyclic vomiting.
Referral to counseling and cannabis cessation programs is appropriate. However, according to Lonsdale, many patients are reluctant to volunteer their history of drug use and it may take a clinician’s use of “open questions” to reveal it. Otherwise, a diagnosis of CVS may be implied.
Cases of CH may be on the rise, concludes Lonsdale. “We think we see early signs of increasing cannabis use by adolescents during the COVID-19 pandemic, and we are currently working on a study investigating whether that is the case,” she says.
Michael Wilsey, M.D., is chief of the medical staff at Johns Hopkins All Children’s Hospital, Inc. (“JHACH”), but is an independent practitioner who is not an employee or agent of JHACH.