CHS is a chronic disorder of gut–brain interaction characterized by cyclic vomiting, nausea, and abdominal pain in the setting of chronic, heavy cannabis use, often with compulsive hot bathing behavior. It is classified as a subtype of cyclic vomiting syndrome (CVS) under Rome IV criteria and is increasingly prevalent with cannabis legalization and rising THC potency. [1-3]
1. History
- Cannabis use details: frequency (typically ≥4 times/week), duration (usually >1 year, mean ~6.6 years before symptom onset), route (smoking, vaping, concentrates), and potency of products [1-2]
- Symptom characterization: stereotypical episodic nausea, profuse vomiting, and diffuse abdominal pain recurring ≥3 times annually [1]
- Three phases: prodromal (early morning nausea, food avoidance), hyperemetic (severe intractable vomiting lasting 24–48 hours, up to 7–10 days), and recovery (symptom resolution, return to normal eating) [4-5]
- Hot water bathing: ask specifically about compulsive hot showers/baths for symptom relief — reported in ~71% of patients; some spend hours in the shower [1][5]
- Timing: episodes often begin in the early morning; ask about temporal relationship to cannabis use (symptoms occur during or within 48 hours of use) [6]
- Prior ED visits: many patients have had multiple presentations with previously negative workups [5]
- Important negatives: absence of fever, bloody emesis, diarrhea, weight loss, and neurologic symptoms
2. Alarm Features
- Dehydration leading to acute kidney injury and electrolyte/metabolic derangements [1]
- Hypokalemia — patients with CHS have significantly lower potassium levels compared to CVS [7]
- Pneumomediastinum or pneumothorax from forceful retching (rare but reported) [1]
- Death — rare but documented, typically from dehydration-related complications [1]
- Features suggesting alternative diagnosis: hematemesis, melena, focal neurologic deficits, peritoneal signs, fever, jaundice
3. Medications
- Effective acute treatments:
- Haloperidol 0.05 mg/kg IV (superior to ondansetron in RCT; reduced ED length of stay by ~2.5 hours) [8]
- Droperidol — also recommended by SAEM GRACE-4 guidelines [3]
- Topical capsaicin 0.075–0.1% cream applied to upper abdomen (activates TRPV1 receptors; mixed evidence but low risk) [1][3]
- Benzodiazepines (parenteral lorazepam) — effective for acute attacks per some experts, but SAEM GRACE-4 recommends against first-line use [3][9]
- Long-term prophylaxis: Amitriptyline 25 mg at bedtime, titrated to 75–100 mg; efficacious in ~70% of patients [1][9]
- Emerging: Aprepitant (NK-1 receptor antagonist) — case reports of rapid symptom resolution when standard therapies fail [10]
- Ineffective/avoid:
- Traditional antiemetics (ondansetron, metoclopramide, prochlorperazine) are typically ineffective [3][6]
- Opioids — proemetic, worsen gastroparesis, high addiction risk; reserve only if haloperidol/droperidol and capsaicin fail [3]
4. Diet
- During hyperemetic phase: NPO until vomiting controlled, then advance to clear liquids
- Aggressive IV hydration is critical — patients are often significantly volume depleted
- During recovery: bland diet, small frequent meals, advance as tolerated
- Long-term: no specific dietary triggers identified; focus is on cannabis cessation rather than dietary modification
- Monitor for and correct electrolyte depletion (potassium, magnesium)
5. Review of Systems
- GI: nausea, vomiting frequency/volume, abdominal pain location and character (classically diffuse), hematemesis, diarrhea, constipation
- Constitutional: weight loss, dehydration symptoms (dizziness, decreased urine output)
- Neuro: headache (migraine association with CVS), focal deficits
- Psych: anxiety, depression, insomnia — commonly comorbid and often drive continued cannabis use [11]
- GU: pregnancy status in reproductive-age patients
- Skin: burns or erythema from prolonged hot water exposure
6. Collateral History and Family History
- Collateral from family/friends regarding actual cannabis use frequency and quantity — patients frequently underreport use [2]
- Family history of migraine or CVS (shared pathophysiology)
- Social context: reasons for cannabis use (anxiety, chronic pain, recreational), willingness to consider cessation
- Screen for concurrent substance use (alcohol, other drugs)
- Assess for cannabis use disorder using validated tools such as the CUDIT-R (Cannabis Use Disorder Identification Test–Revised) [3]
7. Risk Factors
- Daily or near-daily cannabis use (68% of cases) [1]
- Duration of use >1 year (mean 6.6 years before symptom onset) [1]
- High-potency products (vapes, concentrates, waxes) [2]
- Male sex (69% of cases) [1]
- Young age (mean ~30 years) [1]
- Inhalation route (smoking, vaping) — most commonly associated; edible-associated cases are rare [5]
- Possible genetic susceptibility (limited evidence) [2]
8. Differential Diagnosis
- Cyclic vomiting syndrome (CVS) — nearly identical presentation; distinguished by temporal association with cannabis and resolution with cessation [6][12]
- Gastroparesis — consider in young, non-diabetic patients previously labeled with gastroparesis [5]
- Bowel obstruction — surgical emergency; assess for distension, absent bowel sounds, obstipation
- Pancreatitis — check lipase; epigastric pain radiating to back
- Pregnancy — always exclude in reproductive-age patients
- Acute abdomen / mesenteric ischemia — peritoneal signs, hemodynamic instability
- Myocardial infarction — especially atypical presentations with nausea/vomiting
- Rumination syndrome — effortless regurgitation, typically postprandial
- Migraine with GI predominance — headache, photophobia, aura
- Functional chronic nausea and vomiting syndrome [1]
- Adrenal insufficiency, DKA, uremia — metabolic causes of intractable vomiting
9. Past Medical History
- Prior episodes of cyclic vomiting and number of ED visits
- Previous negative workups (endoscopy, CT, labs)
- History of anxiety, depression, or other psychiatric conditions [11]
- Cannabis use disorder or other substance use disorders
- Prior diagnosis of gastroparesis (may actually be CHS) [5]
- Chronic pain conditions driving cannabis use
10. Physical Exam
- Vitals: tachycardia, hypotension (dehydration), elevated systolic BP (CHS patients have higher SBP than CVS) [7]
- General: distressed, diaphoretic, may appear dehydrated (dry mucous membranes, poor skin turgor, sunken eyes)
- Abdomen: diffuse tenderness without peritoneal signs; soft, non-distended; normal bowel sounds. Absence of rebound/guarding is expected — if present, consider alternative diagnosis [5]
- Skin: erythema or burns from prolonged hot water exposure; check for capsaicin application sites
- Neuro: should be non-focal; focal findings warrant brain imaging [1]
11. Lab Studies
- BMP/CMP: assess for hypokalemia, hyponatremia, elevated BUN/creatinine (prerenal AKI from dehydration), metabolic alkalosis [5][7]
- Urinalysis: ketonuria (starvation ketosis), specific gravity (dehydration) [5]
- Urine drug screen: confirm cannabis use if patient denies; positive THC supports diagnosis [5][7]
- Lipase: rule out pancreatitis
- Pregnancy test: all reproductive-age patients
- CBC: mild leukocytosis is common and nonspecific [5]
- Hepatic panel: if concern for hepatobiliary pathology
- Lactate: if concern for mesenteric ischemia or sepsis
- Labs are primarily used to assess complications (dehydration, AKI, electrolyte derangements) and exclude mimics — there is no confirmatory lab test for CHS [1][5]
12. Imaging
- First-line: imaging should be avoided in the setting of a benign abdominal exam and known recurrent presentations — there are no specific radiological findings for CHS [5]
- When indicated: CT abdomen/pelvis to exclude obstruction, pancreatitis, or other acute pathology in first presentations or when exam is concerning [1]
- Abdominal imaging yield is low: only 2.4% of imaging in CHS/CVS patients showed abnormalities in one study [7]
- Brain imaging: only if focal neurologic symptoms or signs [1]
- Upper GI endoscopy: outpatient setting to exclude structural causes if diagnosis uncertain [1]
13. Special Tests
- Rome IV criteria for CVS/CHS — clinical diagnostic framework [1][13]
- CUDIT-R (Cannabis Use Disorder Identification Test–Revised) — validated screening tool for cannabis use disorder [3]
- Urine drug screen — point-of-care confirmation of cannabis use
- Gastric emptying study: consider outpatient if gastroparesis is in the differential
- No specific biomarker or confirmatory test exists for CHS [1]
14. ECG
- Obtain ECG if:
- Significant hypokalemia or other electrolyte derangements (risk of arrhythmia)
- Administering haloperidol or droperidol — monitor for QTc prolongation
- Concern for atypical MI presentation (nausea/vomiting as chief complaint in older patients)
- Dangerous patterns: prolonged QTc, U waves (hypokalemia), ST changes
15. Assessment
- CHS is a clinical diagnosis based on: (1) stereotypical episodic vomiting ≥3 times/year, (2) cannabis use >1 year at ≥4 times/week, and (3) resolution with sustained cannabis cessation [1]
- Predominantly affects young males (~30 years) with heavy, chronic cannabis use [1]
- Frequently misdiagnosed — patients average multiple ED visits and extensive negative workups before diagnosis [2][5]
- Complications: dehydration, AKI, electrolyte derangements, Mallory-Weiss tears, pneumomediastinum (rare), and death (very rare) [1]
- Patients often paradoxically believe cannabis helps their nausea and resist the diagnosis [3][6]
16. Treatment Plan
Acute ED Management
- IV fluid resuscitation — do not delay for other interventions [3]
- Haloperidol 0.05 mg/kg IV (or 2.5–5 mg IV) — first-line per SAEM GRACE-4 and RCT evidence [3][8]
- Droperidol 0.625–1.25 mg IV — alternative dopamine antagonist [3]
- Topical capsaicin 0.075–0.1% cream to upper abdomen — low risk, can be applied by patient; warn about burning sensation [1][3]
- Ondansetron 4–8 mg IV may be tried but is often ineffective as monotherapy [3][8]
- Correct electrolytes (potassium, magnesium) as needed
- Allow hot shower access if available and safe
Long-Term Management
- Cannabis cessation is the only definitive treatment [1][6][14]
- Amitriptyline 25 mg at bedtime, titrate to 75–100 mg — prophylactic mainstay; effective in ~70%; taper after 6–12 months of remission and abstinence [1][9]
- Treat comorbid anxiety, depression, and substance use disorder — critical for cessation success [11]
- Psychosocial interventions and addiction medicine referral [1][3]
- Avoid "cold turkey" cessation without support — significant withdrawal symptoms and high recidivism [1]
17. Disposition
- Discharge criteria: symptoms controlled, tolerating oral fluids, electrolytes corrected, adequate follow-up arranged
- Admission criteria: intractable vomiting despite ED treatment, significant AKI, severe electrolyte derangements, hemodynamic instability, inability to tolerate oral intake
- Observation: consider for patients requiring prolonged IV hydration or repeated antiemetic dosing
- Specialist consultation triggers:
- Gastroenterology — if diagnosis uncertain or refractory symptoms
- Addiction medicine — for cannabis use disorder and cessation support [3]
- Psychiatry — for comorbid psychiatric conditions driving use [11]
18. Follow Up / Return Precautions
- Follow-up: primary care or GI within 1–2 weeks for reassessment and cannabis cessation counseling
- Return precautions: inability to keep down fluids, bloody vomit, severe abdominal pain, dizziness/fainting, decreased urine output, chest pain
- Patient counseling:
- CHS is directly caused by cannabis — symptoms will recur with continued use [6]
- Complete cessation is required for at least 6 months (or duration of 3 typical cycles) to confirm diagnosis and achieve remission [1][13]
- Reducing use may decrease episode frequency but will not eliminate the syndrome [3]
- Hot showers provide temporary relief but are not a treatment — risk of burns and worsening dehydration
- Amitriptyline can help bridge the cessation period and prevent episodes [1][9]
- Expected course: symptoms typically resolve within days to weeks of complete cessation; recurrence is expected with any resumption of cannabis use [6]
Images
References
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2. Cannabinoid Hyperemesis Syndrome, 2016 to 2022. — Swartz JA, Franceschini D. JAMA Network Open. 2025.
3. Guidelines for Reasonable and Appropriate Care in the Emergency Department (GRACE-4): Alcohol Use Disorder and Cannabinoid Hyperemesis Syndrome Management in the Emergency Department. — Borgundvaag B, Bellolio F, Miles I, et al. Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine. 2024.
4. Cannabis Hyperemesis Syndrome in Youth: Clinical Insights and Public Health Implications. — Seabrook JA, Seabrook M, Gilliland JA. International Journal of Environmental Research and Public Health. 2025.
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10. Cannabinoid Hyperemesis Syndrome in Adolescents: The Role of Aprepitant as a New Treatment Option for Rapid Symptom Relief. — Sigal A, Padilla G, Carroll T, Mautone SG. The Journal of Adolescent Health : Official Publication of the Society for Adolescent Medicine. 2025.
11. Current Recommendations in the Diagnosis and Management of Cannabinoid Hyperemesis Syndrome. — Meyer J, Burns MM. Current Opinion in Pediatrics. 2025.
12. Evaluation and Treatment of Nausea and Vomiting in Adults. — Johns T, Lawrence E. American Family Physician. 2024.
13. Proper Counseling for Diagnosis and Management of Cannabinoid Hyperemesis Syndrome: A Case Report. — Cholette-Tétrault S, Grad R. Family Practice. 2025.
14. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition 2025 Guidelines for Management of Cyclic Vomiting Syndrome in Children. — Karrento K, Rosen JM, Tarbell SE, et al. Journal of Pediatric Gastroenterology and Nutrition. 2025.