A 23-year-old female with no past medical history presents to the ED for the 4th time this month complaining of severe “10-out-of-10” abdominal pain, nausea, and intractable vomiting. She denies alcohol use, but reports she has smoked at least 1 marijuana “bud” daily for the last 3 years. In an attempt to relieve her symptoms, she has increased her marijuana use, however she has found that her pain is actually increasing, and the only thing that appears to help is taking a hot shower or bath. With this statement, the provider immediately considers cannabinoid hyperemesis syndrome (CHS).
Cannabinoid Hyperemesis Syndrome
Cannabinoid hyperemesis syndrome (CHS) was first described in Australia in 2004 and is characterized by years of cannabis abuse, cyclic episodes of nausea and vomiting, and a learned behavior of hot bathing or showering.1
Δ9 -tetrahydrocannabinol (THC) is the principle active compound of cannabis, and acts similarly as an endogenous cannabinoid on cannabinoid receptors.2 The human body has 2 distinct cannabinoid receptors, CB1 and CB2. The CB1 receptors have been identified in multiple organ systems, including the brain, spleen, liver, heart, uterus, bladder, and gastrointestinal system. Less is known about CB2 receptor effects; they are likely involved in the inhibition of inflammation, visceral pain, and intestinal motility. It has been hypothesized that THC is the causative agent of CHS by chronic stimulation of CB1 and CB2 receptors, resulting in gastrointestinal disturbances.2
CHS is often under-recognized and diagnosed only after multiple visits to the ED and extensive workups.
Proposed clinical criteria for CHS include:
- Long-term weekly cannabis use
- Abdominal pain
- Severe cyclic nausea and vomiting
- Relief of symptoms with hot showers3
The most effective long-term treatment is the cessation of cannabis use. In the ED, treatment is directed towards symptom management. Intravenous hydration, electrolyte replacement, and pharmacologic alleviation of nausea, vomiting, and abdominal pain are the mainstays of therapy. Opioids for relief of abdominal pain should be avoided, as they may exacerbate nausea and vomiting.4 Typical antiemetics such as ondansetron, promethazine, prochlorperazine, and metoclopramide are infrequently effective as monotherapy. Treatment with haloperidol or droperidol should be considered, as they provide antiemetic effects likely due to D2 dopamine receptor antagonism in the central nervous system.4 A case report found that patients had resolution of their symptoms within 2 hours of receiving haloperidol, and were able to discharge from the ED within 8 hours.5 Benzodiazepines, such as lorazepam, should also be considered as a treatment option, especially for associated anticipatory nausea.4
There are various pharmacologic interventions to treat the symptoms of CHS, but what else can be done? As mentioned, patients with CHS compulsively take hot showers and report relief of symptoms during the shower. Hot water activates transient receptor potential vanilloid 1 (TRPV1) receptors, resulting in impaired substance P signaling in the area postrema and nucleus tractus solitarius.6 It is unlikely feasible to have patients shower in the ED for symptom relief; however, there is a pharmacologic trick to get the same effect.
Trick of the Trade – Apply Capsaicin Cream to the Abdomen
Topical capsaicin cream binds to TRPV1 receptors with high specificity, impairing substance P signaling, much like a hot shower. In multiple case series and reports, capsaicin cream used in the ED was found to provide adequate relief of symptoms:
- Case series of 13 patients in 2 academic medical centers diagnosed with CHS were treated with capsaicin cream and had improvement in symptoms after other treatments failed7
- Case series of 5 patients with chronic cannabis use diagnosed with CHS and treated successfully with 0.075% capsaicin cream8
- Case report of 1 patient with CHS, treatment failed with metoclopramide and granisetron, but had successful treatment with 0.075% capsaicin cream9
- Case report of 1 patient with CHS, no relief of symptoms with zofran, treated successfully with 0.025% capsaicin cream10
Bonus Trick of the Trade
If topical capsaicin irritates any sensitive areas outside the abdomen, rinse the area with milk to alleviate quickly! The milk protein, casein, acts as a natural detergent and breaks up the capsaicin.11