Is marijuana making your patient sick?
The differential diagnosis for nausea and vomiting is very broad, including several gastrointestinal, peritoneal, central nervous system, endocrine, psychiatric, and metabolic causes. Given the recent rise in marijuana legalization efforts and an overall increase in the prevalence of marijuana use, it is becoming increasingly important to recognize conditions that are associated with its use.
In 2004, a small case series described nine patient’s with similar symptoms:
- Cyclical episodes of profuse vomiting, occurring every few weeks or months. The vomiting was often accompanied by colicky abdominal pain, diaphoresis, and polydipsia. Symptoms had typically continued for many years, requiring multiple hospital admissions and extensive GI workups that never established an alternate diagnosis. Vomiting tended to be resistant to treatment with antiemetics.
- A history of regular daily cannabis use, usually over a period of at least several years predating the onset of cyclic vomiting.
- Relief of symptoms when the patient took a hot bath or shower. This resulted in compulsive bathing behavior, a striking characteristic that was the most unusual manifestation of this syndrome and is considered pathognomonic.
- Vomiting episodes ceased when patients refrained from cannabis use, and symptoms returned if cannabis use was resumed.
The pathophysiology of Cannabinoid Hyperemesis Syndrome is not well understood at this time. There are multiple proposed theories regarding the development of CHS but no definitive evidence or single mechanism has yet been identified. Possible contributing factors include slowed gastric motility and impaired peristalsis by CB1 receptors in CNS and enteric plexus. Another proposed theory involves the chronic activation of these receptors that lead to a paradoxical emetic effect. THC in marijuana is an extremely fat-soluble compound so stores for long periods of time in fat tissue. When a marijuana user inhales THC it quickly reaches the brain to give the typical euphoric “high” sensation. It then slowly absorbs into the fat tissue where it gets stored. As the THC in the bloodstream from the initial use begins to decrease, there will be a slow “leech” of THC from the fat tissues back into the bloodstream. With chronic marijuana use, this amount of THC that gets leeched back into the bloodstream is theorized to lead to chronic activation of CB1 receptors, potentially causing a paradoxical effect on the normal receptor activation.
Treatment often is supportive with emphasis placed on marijuana cessation. Intravenous fluids often are used due to dehydration from the emesis. The use of antiemetics can be tried, but are often are ineffective. Diet can be advanced as the patient tolerates. Given that many patients are found to have mild gastritis, H2 blockers or proton pump inhibitors may be used. Extensive counseling on marijuana cessation is needed as it is the only therapy shown to have prolonged relief of the hyperemetic phase. Other medications that have been used with some success in patients include Benzodiazepines and Haldol.
Jeff Lapoint, DO, an emergentologist and medical toxicologist at Kaiser-Permanente in San Diego was researching another subject and came across a description of the TRPV1 receptor, a protein found in the peripheral nervous system. It is activated by exposure to scalding heat (>109°F) and to capsaicin, the compound in chili peppers that produces a burning sensation when it comes into contact with skin or mucous membranes. In fact, TRPV1 is the only receptor in the human body that reacts to capsaicin.
Seeing how the TRPV1 receptor was activated by exposure to very hot temperatures and capsaicin, he wondered if capsaicin could be used for cannabinoid hyperemesis. Many patients with symptoms have been successfully treated with the application of capsaicin cream (0.075%) to the abdomen. Symptoms resolved or dramatically diminished within 30-45 minutes with application of capsaicin cream to the skin. Some case reports have applied the cream to the abdomen, others spread the cream across the body on the arms, legs, and torso. The authors suggest that response to topical capsaicin can be diagnostic and therapeutic in these patients.
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