Cannabinoid hyperemesis syndrome: an important differential diagnosis of persistent unexplained vomiting

Chronic nausea and vomiting have a detrimental impact on quality of life. When standard diagnostic investigations fail to provide a definitive diagnosis, patients are often attributed as having a functional gastrointestinal disorder such as cyclic vomiting syndrome. Cannabinoid hyperemesis syndrome (CHS) is a relatively recently described entity presenting with symptoms similar to cyclic vomiting syndrome.

We carried out a retrospective cohort study of all patients attending a tertiary neurogastroenterology and secondary care gastroenterology clinic from 2013 to 2015. Data were obtained by review of clinical notes, letters and electronic patient records.

We identified 10 cases of CHS (five men, mean age 27 years, range 19-51), who hitherto had been labelled with a variety of alternative diagnoses. All patients had symptoms that were episodic and refractory to medical therapy. Patients had experienced symptoms for a mean of 19.3±11.09 months before diagnosis. The median length of cannabinoid use was 42 months (interquartile range: 15-81.8). Eight patients (80%) had a history of compulsive hot water bathing (hydrophilia). The patients had a median follow-up of 9.5 months (range 1-20), during which symptoms recurred in three patients who returned to regular cannabis use.

CHS is an underappreciated cause of recurrent nausea and vomiting and is frequently misdiagnosed. Healthcare providers should have a low index of suspicion for diagnosing CHS and the clinical history in such patients should routinely include direct questioning on cannabis use. The prognosis is very good upon cessation of cannabis intake.