Cannabinoid Hyperemesis Syndrome

Patients diagnosed with cannabinoid hyperemesis syndrome that are safe for discharge from the emergency department will be sent an outpatient prescription for haloperidol to be used as needed at home. The study goal is to see if having this medication available helps to prevent return emergency department visits for recurrent or persistent symptoms.

The aim of the study is to identify which medication (haloperidol or olanzapine) is most effective in treating nausea and abdominal pain associated with cannabinoid hyperemesis using a 10-point visual analog scale with intervals of 0.5.

Cannabinoid hyperemesis syndrome (CHS) is characterized by incoercible abdominal pain and vomiting in patients with chronic cannabis use. Patients are relieved by hot showers, an easily performed diagnostic test. The prevalence of this syndrome in France is not well known. A single French study from 2021, carried out in two Marseille emergency departments, estimated a 1.6% prevalence of CHS (48 cases / 2848 patients) in patients consulting for acute abdominal pain with no etiology found over a 10-month period. Cannabis is the most widely used illicit substance in France. France is also the second biggest cannabis consumer in Europe, with around 11% of the French population currently using the drug (use within the year). Despite growing attention to CHS, the diagnosis and management of this syndrome remains difficult, with repeated visits to emergency departments often required before a diagnosis is made. What's more, once the diagnosis has been made, the severity of symptoms can lengthen the emergency room length of stay. Main objective: To estimate the incidence of cannabinoid hyperemesis syndrome among patients admitted on a first visit for abdominal pain and/or vomiting to the Maine et Loire emergency department. Primary endpoint: The incidence of cannabinoid hyperemesis syndrome among patients presenting with abdominal pain and/or vomiting, consulting adult emergency departments in Maine et Loire. Cannabinoid hyperemesis syndrome will be considered in all patients admitted for abdominal pain and/or vomiting, who are regular cannabis users (weekly use for more than 6 months declared by questionnaire) and in whom no other etiology is accepted after any additional examinations. Research plan and procedure: It is an observational, prospective, multi-center cohort study. Participation in the study is offered to any emergency room patient who meets all inclusion criteria and none of the non-inclusion criteria. Patients are included after reading the information note. Consent is obtained on a no-objection basis. A questionnaire is given to participants via a QR code with an identification number generated by the investigating physician. This QR code opens an online questionnaire that the patient can fill in while in the emergency department. In the absence of access to the QR code (no cell phone), the questionnaire will be given to the participant in paper format by the investigating physician. It will be collected at the end of the inclusion visit. Participants who have revealed cannabis use (at least 1 time per week for at least 6 months) via the questionnaire are followed up at 3 months (+/- 15 days) by telephone to assess the evolution of symptoms, any recurrences, medical treatment and whether or not cannabis has been withdrawn. Inclusion criteria: * Patients aged 18 to 65 years, * Consulted an adult emergency department in Maine et Loire for abdominal pain and/or vomiting for the 1st time during the study period. Non-inclusion criteria: * Refusal to participate in the study * Patient unable to answer the questionnaire (allophone, under guardianship, under protection, incapable of major age, in the process of legal proceedings) * Pregnant women Number of research participants: At present, there are no data on the incidence of CHS in the French literature. In order to assess the number of subjects required, we made a projection based on the only French study to date. In this study, carried out in two departments in Marseille, the percentage of patients with CHS among those consulting the emergency department for acute abdominal pain was 1.6%. Thus, assuming that the proportion of the event will be identical to that of the study carried out in Marseille, i.e. 1.6%, it would be necessary to recruit 3,000 people with abdominal pain and/or vomiting to have around 50 patients with CHS. Research duration: Inclusion period: 12 months Duration of participation: 3 months +/- 15 days (for patients with CHS) Study duration: 15 months