Cannabinoid Hyperemesis Syndrome: A Case Report and Discussion Regarding Patients with Concurrent Disorders.

In October 2018, Canada legalized the nonmedical use of cannabis. Usage has traditionally been high in Canada, and after legalization, self-reported use increased from 14% to 18%.1 Given this increased usage, it is important to understand the adverse effects of cannabis. Here, we focus on a less well-recognized consequence, cannabinoid hyperemesis syndrome (CHS), first described in 2004.2 It may be seen more often in jurisdictions where cannabis is legalized; for example, from 2009 to 2011, after legalization of cannabis in the state of Colorado, presentations to emergency departments for CHS increased by almost 100%.3 CHS presents similarly to cyclic vomiting syndrome, with recurrent nausea and vomiting episodes interspersed with asymptomatic periods.4 However, several features differentiate CHS from cyclic vomiting syndrome. CHS is associated with a history of chronic cannabis use, cure of the syndrome after cessation of cannabis, and delayed gastric emptying.4 Cyclic vomiting syndrome is often associated with concurrent migraines and psychiatric conditions, as well as rapid gastric emptying.4 The prodromal phase lasts up to several years in CHS,4 but just minutes to hours in cyclic vomiting syndrome.5 The following characteristics seem to have the highest sensitivity for diagnosis of CHS: weekly cannabis use for more than 1 year, severe nausea and vomiting with abdominal pain repeating in a cyclic pattern over months, resolution of symptoms after cannabis cessation, and compulsive use of hot baths or showers to provide temporary symptom relief.6 Normal bowel habits are cited as supportive criteria. However, abnormal bowel habits do not necessarily rule out CHS, as there are a number of recorded cases, including the patient described in this report, with both CHS and abnormal bowel habits.7 The complications of CHS, which are due to recurrent vomiting, include fluid and electrolyte disorders, nutritional deficiencies, aspiration, pneumonitis, and esophageal wall injury.8 Unfortunately, given that CHS is poorly recognized, patients often undergo potentially harmful procedures such as radiography, computed tomography (CT), endoscopy, and appendectomy in search of a diagnosis.4 Here, we describe CHS by means of a clinical case and then discuss the challenges that may be encountered within the subpopulation of patients with concurrent disorders.