Cannabinoid hyperemesis syndrome explained CANNABIS USE in the United States continues tion between their symptoms and cannabis to increase. With the legalization of recre- use because the symptoms don’t occur imme- ational cannabis in 11 states and Washington, diately after consumption. DC, as well as medical legalization in 33 states, a record number of Americans are con- Hyperemetic phase suming cannabis. According to a recent poll, The hyperemetic phase is characterized by 24 approximately 34 million American adults use to 48 hours of intense vomiting, epigastric or cannabis on a regular basis (at least twice diffuse abdominal pain, sweating, and flush- monthly). With this rise in use comes a new ing. Vomiting occurs as frequently as four or set of challenges for healthcare professionals, more times per hour. Nausea and vomiting in including an increase in cannabinoid hyper- this phase are refractory to antiemetic medica- Learn how to emesis syndrome (CHS), a poorly understood tions. Weight loss and dehydration are com- condition that affects habitual cannabis users. mon. Most patients in this phase cease identify this cannabis use because of the intensity of their Signs and symptoms symptoms. When patients learn—usually by frequently CHS is a cyclical three-phase (prodromal, hyper- accident—that hot showering and bathing re- emetic or vomiting, and recovery) syndrome. lieves symptoms, the behavior may become misdiagnosed compulsive; some patients take up to 12 hot condition. Prodromal phase showers or baths per day during this phase. The prodromal phase is characterized by Many patients say that the hotter the water, By Charlotte Skinner, days, weeks, or months of mild symptoms. the greater their relief, and some describe it as BSN, RN-C Researchers frequently describe them as simi- “washing away” their nausea. lar to the “aura” of migraines because they precede an intense worsening of symptoms. Recovery phase In this phase, patients experience nausea, mild The recovery phase begins when vomiting GI discomfort, and anxiety or restlessness. ends and only after patients cease using Symptoms are more commonly experienced cannabis. During this phase, patients are rela- in the morning but may be felt throughout the tively symptom free; their eating habits return day. Patients’ eating habits are unchanged, to normal, they gain weight, and they stop and weight loss and vomiting are minimal or compulsively showering or bathing. Many pa- absent. Many patients continue or increase tients resume cannabis use because they’re their cannabis use because they believe it will unable or unwilling to make the connection ease symptoms; they don’t make the connec- between it and their illness. In all studied cas- 6 American Nurse Journal Volume 15, Number 4 MyAmericanNurse.com 7 characteristics of CHS The following characteristics have been found to occur in patients with cannabinoid hyperemesis syndrome (CHS). es, resumption of cannabis use caused symp- Characteristic Frequency toms to recur. This recurrence is compelling evidence that cannabis is the root cause of History of regular cannabis use for any duration of time 100% CHS, making a history of cannabis use essen- tial for diagnosis. Cyclic nausea and vomiting 100% At least weekly cannabis use 97.4% Presentation and diagnosis Resolution of symptoms after stopping cannabis 96.8% Most patients with CHS present in the hyper- emetic phase, complaining of intense nausea, Compulsive hot baths with symptom relief 92.3% vomiting, and abdominal pain. The patient’s Abdominal pain 85.1% hair may be wet because of compulsive show- ering or bathing. The differential diagnosis list Male predominance 72.9% for nausea, vomiting, and abdominal pain is Source: Sorenson et al 2017 long, but seven characteristics identified in people with CHS may aid in diagnosis. (See 7 characteristics of CHS.) proemetic effect in the gut (perhaps due to Imaging (X-rays and computed tomogra- tolerance), resulting in CHS. phy scans) is negative for findings in patients In addition, THC is lipid-binding and can with CHS. And despite the intense GI symp- be stored within the body’s fat cells to poten- toms and epigastric pain, endoscopy also is tially toxic levels with repeated, frequent use. negative. Laboratory studies may reveal dehy- In times of stress or illness, the stores of THC dration and subsequent electrolyte imbalance may be released from fat as it’s metabolized or acute renal failure, but will otherwise be by the body, triggering or perpetuating CHS unremarkable. symptoms. The thermoregulatory effects of Within primary care settings, patients may THC on the hypothalamus may be why hot report a history of emergency department baths and showers become a learned compul- (ED) visits and/or hospitalizations related to sion for symptom management. nausea, vomiting, and dehydration. They also Most cannabis users don’t develop CHS. may have a documented history of canna bis Possibly an unknown genetic or environmen- use. Consider CHS in patients with a reported tal trigger is an underlying contributor for or documented history of cyclical nausea and those who do develop it. And although CBD vomiting, negative imaging and lab studies, and CBG may contribute to CHS, THC is a and known cannabis use. necessary component of the syndrome. CBD in the absence of THC, for example, hasn’t Etiology been linked to CHS. More research is being The cause of CHS isn’t fully understood, but it conducted to understand the connection be- may be related to the effects of three compo- tween genetics and the environment in CHS. nents of cannabis: tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabigerol (CBG). Treatment These chemical components work in the brain CHS treatment revolves around symptom and the gut, where a host of canna binoid re- management and cannabis cessation. In the ceptors (CB1 and CB2) reside. (See The endo- hyperemetic phase, expect the patient to re- cannabinoid system.) In the central nervous quire I.V. fluids, rest, and monitoring for com- system (CNS), THC, CBD, and CBG have a va- plications of dehydration. Inpatient care may riety of effects, one of which is potent be required, especially for patients with elec- antiemetic properties; THC has thermoregula- trolyte imbalances or acute renal failure sec- tory effects within the hypothalamus. ondary to dehydration. In the enteric system, THC, CBD, and CBG Traditional antiemetic medications such as actually have proemetic effects, but they’re ondansetron, promethazine, prochlorper- thought to be “overridden” by the antiemetic azine, and metoclopramide generally aren’t actions of these chemicals in the brain, result- effective in CHS. New research has shown ing in a net antiemetic effect. However, when some effectiveness with dopamine antagonists cannabis is chronically and frequently used, (such as haloperidol and ziprasidone) and its CNS effects may be overcome by the benzodiazepines in inpatient and outpatient MyAmericanNurse.com April 2020 American Nurse Journal 7 The endocannabinoid system The body’s endocannabinoid system consists of cannabinoid recep- tors (CB1 and CB2 are the most common), ligands, and enzymes. their symptoms. (See A topical solution.) • Receptors can be stimulated by endogenous or exogenous (plant- derived or synthetic) cannabinoids. The only cure for CHS is the complete ces- • sation of cannabis and its derivatives, but this Ligands act as chemical messengers to get cannabinoids to interact may be challenging for patients with cannabis at the receptor site. • use disorder. This complex and multifaceted Enzymes break down cannabinoids after they’ve completed their psychological and physiological disorder may function. be accompanied by other conditions—such as Source: Theisen and Konieczny 2019 anxiety, depression, chronic pain, post-traumat- ic stress disorder, and insomnia—that compli- cate cessation efforts. Patients will need coun- settings, although more studies are needed. seling, medications, and other support services. Opioid analgesics provide little to no change in patients’ abdominal pain and have the po- Challenges tential to worsen nausea and vomiting. Pa- Diagnosing and treating CHS presents a num- tients should be allowed to bathe or shower, ber of unique challenges. Some patients may when appropriate, for symptom relief. be misdiagnosed with cyclical vomiting syn- Applying capsaicin-based creams to the ab- drome or other GI disorders, especially if domen may relieve the nausea and vomiting they’re not forthcoming about their cannabis associated with CHS. Capsaicin, a chili-pepper use. The result may be years of suffering, un- derivative commonly used in topical creams necessary tests, and recurrent ED visits and to treat musculoskeletal pain, is thought to hospitalizations. Studies show that people cause vasodilation and disrupt the impaired with CHS may visit the ED three to 11 times thermoregulatory processes contributing to before diagnosis. Suggest the provider order a the patient’s symptoms; it’s considered a sub- urine drug screen for patients with a history of stitute to hot water bathing. In a study by Gra- cyclical nausea and vomiting that’s relieved ham and colleagues, 13 adolescents with CHS with hot water bathing but who deny were treated with capsaicin cream applied top- cannabis use. ically to their abdomens during the hyperemet- Some patients may not make the connec- ic phase; 100% of the participants reported tion between their symptoms and cannabis complete resolution or a significant decrease in use. The widely known antiemetic properties of cannabis make the paradoxical symptoms of CHS difficult for many patients to accept, A topical solution especially if they have cannabis use disorder. Communicate in a way that fosters patient Capsaicin-based cream applied to the abdomen has been show to re- trust in the healthcare team to encourage early lieve symptoms of cannabinoid hyperemesis syndrome. Follow these diagnosis and treatment. Be factual and instructions for use. straightforward when explaining CHS to pa- • Verify the order using the five rights of medication administration. tients, and advocate for necessary supportive • measures to aid cannabis cessation.