A 30-year-old woman presents with debilitating nausea and vomiting. The vomiting occurs in a cyclical pattern, with the patient experiencing episodes every few months. She is also complaining of colicky abdominal pain but her bowel movements are normal.
She states that the only thing that helps when the vomiting episodes occur is taking hot baths. She has no past medical history of note but admits to being a long-term heavy cannabis smoker. You organize a full set of bloods and an abdominal X-ray, both of which are entirely normal.
1. What is the most likely diagnosis?
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This patient has a diagnosis of cannabinoid hyperemesis syndrome (CHS), which is a very rare form of cannabinoid toxicity that develops in chronic smokers.
It is characterized by cyclic episodes of debilitating nausea and vomiting. One of the most characteristic features of the syndrome is that people who suffer from it often find hot baths and showers relieve their symptoms, and will compulsively bathe during episodes of nausea and vomiting.
CHS develops in heavy, longtime consumers of cannabis; there is generally daily use in excess of three to five times a day for many years before the appearance of symptoms. One study showed that the average duration of cannabis use before the onset of symptoms was around 16 years, and the earliest symptoms had developed in a patient was after around three years of use.
2. Which criteria can help with the diagnosis?
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Sontineni and colleagues developed the following criteria for cannabinoid hyperemesis syndrome in 2009 to offer guidelines for clinical diagnosis:
| Essential criteria | Cannabis use for years (mean duration 16 years) |
| Major criteria | Severe nausea and vomiting Vomiting that recurs in a cyclic pattern over months Resolution of symptoms after stopping cannabis use |
| Supportive criteria | Compulsive hot baths with symptom relief Colicky abdominal pain No evidence of gallbladder or pancreatic inflammation |
3. What is the pathogenesis of this condition?
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The pathogenesis of CHS is not fully understood but several theories have been suggested.
The two main postulated theories are:
- That there is a dose-dependent build-up of cannabinoids and this results in CHS due to cannabinoid toxicity.
- That there is an effect upon the functionality of the cannabinoid receptors in the brain, particularly in the hypothalamus, which results in CHS.
4. How is this condition treated?
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Most conventional anti-emetic drugs are effective in the vomiting phase of the syndrome. During acute episodes careful attention must be paid to the patient’s hydration status as the combination of hot baths and protracted vomiting can lead to cannabinoid hyperemesis acute renal failure (CHARF), which is easily prevented and treated with intravenous fluids.
Once the vomiting and dehydration of the acute episode has been treated, the condition is easily cured by stopping the consumption of cannabis.
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