乌鸦传媒

The liberalization of marijuana use is widely expected to result in increased exposure to one of its primary active ingredients, tetrahydrocannabinol (THC). Of the various potentially therapeutic effects of medical cannabis, its antiemetic, appetite-stimulating benefits in chemotherapy patients are among the earliest to be documented, in 1975. However, much remains unknown about the effects of this largely uncontrolled substance. This reports a paradoxical emetic effect in a long-time, daily cannabis user, marked by an unexpected behavioral response.

The Case

A 26-year-old Caucasian male in the Caribbean presents at hospital with a 1-week history of intense, intermittent abdominal pain. He describes the stomach pain as dull and aching, and says it is somewhat alleviated by vomiting. He reports regular bowel function, and has no fever, chills, or other flu-like symptoms.

His immediate history reveals that for about 3 weeks before the onset of his stomach pain, he was experiencing nausea with vomiting about 20 times a day and frequent episodes of retching. He says that each day, he takes up to 15 hot showers, which he finds provide some temporary relief from the nausea. The showers can last an hour or longer.

He does not drink alcohol or smoke tobacco. However, he admits to smoking about four marijuana joints daily for the past 2 years.

A more extensive history reveals that he has been admitted to the hospital 4 times over the past 6 months for treatment of these same symptoms.

Previous hospital treatments involved rehydration and antiemetics, and abdominal imaging, which showed no abnormalities.

Diagnosis of Exclusion

The differential diagnosis for nausea and vomiting is very broad. Long-term cannabis use, typically weekly or daily, is the key diagnostic criteria, with severe cyclic nausea and vomiting alleviated with hot showers or baths, and epigastric or periumbilical abdominal pain. The by discontinuation of cannabis use.

Diagnostic Workup Findings

• Urine drug screen is positive for THC
• Blood tests results show normal complete blood count and normal renal and hepatic function
• Abdominal computed tomography scan reveal no abnormalities
• An esophagogastroduodenoscopy and biopsy identify mild gastritis negative for Helicobacter pylori

Treatment and Outcome

The patient is admitted for intravenous fluid rehydration and antiemetics.

Initially, treatment with antiemetics and morphine has little effect on his symptoms.

In the absence of access to marijuana, the patient's symptoms gradually improved over the course of the following 2 days, and his medications were tapered and discontinued.

Case Follow-up

Although the patient was unwilling to participate in the recommended substance-abuse program, he did not return to smoking marijuana. Follow-up assessments at 1, 3, and 6 months indicated no recurrence of symptoms.

Discussion

This 2013 report is thought to be the first documented case of cannabinoid hyperemesis syndrome (CHS) in the Caribbean. CHS affects chronic users of marijuana, and is marked by cyclical vomiting, vague abdominal pain, and learned compulsive hot showering.

Awareness of this may become increasing important with the potential for wider cannabis use. A recent commentary on the condition notes that after liberalization of marijuana in Colorado, there was a near doubling of emergency department visits for cyclic vomiting.

Long-term cannabis exposure is required for the diagnosis, although reports of duration of use prior to onset of symptoms typically range from 1 to 5 years, to longer delays of up to 16 years in some cases.

The observed toxic effects of chronic marijuana use are thought to be related to the uninterrupted stimulation by THC of cannabinoid (CB) receptors in the gut and the brain, manifesting as cyclical hyperemesis.

Possible factors proposed to contribute to this toxic potential include the relatively slow clearance of THC from the system, which could result in accumulation, its fat solubility, delayed gastric emptying, and disturbed thermoregulatory and autonomic responses (i.e., sweating, flushing, thirst, and changes in body temperature) due to the effect on the limbic system -- in particular, on the hypothalamic-pituitary-adrenal axis.

Hence, the symptomatic relief provided by hot water bathing has been theorized to be related to reversal of the chronic stimulation of the CB1 receptor near the thermoregulatory center of the hypothalamus, or secondary to vasodilation of the skin, which redirects blood flow from the gut in an effect referred to as "cutaneous steal."

CHS is characterized as having three phases:

• The prodromal phase is marked by nausea without vomiting, with symptoms often predominating early in the day
• The hyperemesis phase involves cyclical periods of frequent vomiting and retching, vague abdominal pain, and compulsive hot bathing; symptoms may return as frequently as every month or two, with a reported average recurrence of 7 times per year
• With prolonged abstinence from marijuana, the recovery phase begins, marked by return to normal behavior; however, resumption of marijuana use usually results in recurrence of the hyperemesis phase

Conclusion

This case adds to a growing number of reports of these symptoms in chronic users of marijuana. Notably, access to high-potency, genetically engineered marijuana may increase the risk for CHS among chronic long-term users. Awareness of the features of CHS will help physicians and their patients avoid unnecessary and costly diagnostic procedures and treatments.

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