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History
HPI overview
Symptom characterization
Recurrent episodes of severe nausea and vomiting
Symptom free intervals between episodes
Similar prior presentations with negative workups
Pattern consistent with cannabis hyperemesis syndrome
Cannabis exposure
Daily or near daily use for months to years
High potency products
Concentrates or vaping
Recent change in amount or formulation
Last use timing relative to symptom onset
Hot bathing behavior
Compulsive hot showers or baths for relief
Duration and frequency of hot bathing
Trigger context
Stress
Sleep disruption
Dietary indiscretion
Intercurrent illness
Prior treatments and response
Ondansetron response
Dopamine antagonist response
Capsaicin response
IV fluids response
Baseline status
Baseline oral intake
Baseline weight trend
OPQRST
OPQRST framework
Onset
First episode onset date
Current episode start time
Cyclic pattern over days
Provocation and palliation
Worsened by oral intake
Relief with hot showering
Relief with dopamine antagonists
No relief with typical antiemetics
Quality
Nausea severity
Retching
Nonbilious emesis
Region and radiation
Epigastric discomfort
Diffuse abdominal pain
No focal peritoneal localization
Severity
Episodes per hour
Inability to tolerate oral intake
Dehydration severity indicators
Timing
Morning predominance
Episode duration
Interval between episodes
Associated symptoms
GI and systemic
Abdominal pain
Diarrhea
Constipation
Hematemesis
Melena
Fever
Weight loss
Poor urine output
Neuro and cardiopulmonary
Headache
Dizziness
Syncope
Chest pain
Dyspnea
Palpitations
Alarm Features
Immediate escalation triggers
Resuscitation triggers
Hypotension or shock
Altered mental status
Respiratory distress
Persistent tachycardia with dehydration
Uncontrolled vomiting with inability to protect airway
High risk abdominal features
Peritoneal signs
Severe focal tenderness
Abdominal distension with obstipation
Bilious vomiting
GI bleeding
Vital sign danger thresholds
Concerning vitals
Systolic blood pressure less than 90 mmHg
Heart rate greater than 130 beats per minute
Respiratory rate greater than 30 per minute
Oxygen saturation less than 92 percent on room air
Temperature 38.0 C or higher
Special population red flags
Pregnancy related
Pregnancy positive test
Severe dehydration with ketonuria
Older adult or immunocompromised
New onset vomiting without prior cyclic pattern
Concern for obstruction
Concern for infection
Medications
Current and recent exposures
Medication reconciliation
Prescribed medications
OTC medications
Supplements
Recent antibiotic exposure
Recent medication changes
Emetic medications and toxins
GLP 1 receptor agonists
Opioids
Cannabis co exposures
Alcohol
Stimulants
Antiemetic risks and interactions
QT prolongation and sedation risks
Haloperidol exposure
Droperidol exposure
Ondansetron exposure
Other QT prolonging agents
Electrolyte depletion
Contraindications
Parkinson disease or Lewy body dementia
Prior neuroleptic malignant syndrome
Severe dystonia history with dopamine antagonists
Diet
Intake and hydration pattern
Recent intake
Duration of poor oral intake
Last tolerated solids
Last tolerated liquids
Hydration markers
Thirst
Dry mucosa
Oliguria
Orthostasis
Dietary triggers and substances
Exposures
Caffeine and energy drinks
High fat meals
Large meals after fasting
Alcohol exposure
Review of Systems
System review focused
Constitutional
Fever
Chills
Weight loss
GI
Abdominal pain
Diarrhea
Constipation
GI bleeding
GU
Dysuria
Flank pain
Vaginal bleeding
Neuro
Headache
Focal deficits
Seizure
Cardiorespiratory
Chest pain
Dyspnea
Palpitations
Collateral History and Family History
Collateral and reliability
Source
Family or friend report of cannabis use pattern
EMS report of hot shower behavior
Reliability limitations
Family history
Relevant conditions
Migraine
Cyclic vomiting syndrome
Early cardiovascular disease
Inherited metabolic disorders
Risk Factors
Exposure and behavioral risks
Cannabis risk profile
Daily use
Early onset use
High potency THC
Concentrates
Withdrawal cycles with relapse
Dehydration risks
Limited access to fluids
Repeated emesis
Heat exposure from prolonged hot bathing
Medical risks and complications
Complication risks
Electrolyte depletion
Acute kidney injury from volume loss
Aspiration
Esophageal injury
Rhabdomyolysis risk with prolonged agitation or immobility
Differential Diagnosis
Life threatening
Life threatening vomiting causes
Bowel obstruction
Bilious emesis
Distension
Obstipation
Perforated viscus
Peritoneal signs
Severe sudden pain
Upper GI bleeding
Hematemesis
Melena
DKA
Hyperglycemia
Ketonemia or ketonuria
Metabolic acidosis
Adrenal crisis
Hypotension
Hyponatremia
Hyperkalemia
Intracranial pathology
New severe headache
Focal neurologic deficits
Papilledema
Common
Common vomiting causes
Cannabis hyperemesis syndrome
Chronic cannabis use
Hot shower relief
Cyclic course
Viral gastroenteritis
Sick contacts
Diarrhea
Gastritis or peptic ulcer disease
Epigastric pain
NSAID exposure
Pancreatitis
Epigastric pain radiating to back
Lipase elevation
Biliary colic or cholecystitis
RUQ pain
Postprandial triggers
Pregnancy related nausea and vomiting
Positive pregnancy test
Early gestation timing
Less common
Less common and mimics
Cyclic vomiting syndrome (G43.A0)
Migraine history
Triggered by stress
No cannabis exposure
Gastroparesis
Diabetes
Early satiety
Cannabinoid withdrawal nausea
Recent cessation
Irritability and sleep disturbance
Toxic ingestion
Salicylates
Alcohols
Appendicitis
Migratory pain
RLQ tenderness
Past Medical History
Relevant chronic conditions
Chronic conditions
Cannabis use disorder
Anxiety
Depression
Migraine
Diabetes mellitus
Chronic kidney disease
Prior similar episodes
Number of prior ED visits
Prior admissions
Prior diagnostic imaging results
Surgical and procedural history
Abdomen related procedures
Prior abdominal surgery
Prior endoscopy
History of bowel obstruction
Physical Exam
General and vitals interpretation
General appearance
Volume depletion signs
Toxic appearance
Agitation and repeated retching
Hemodynamic assessment
Orthostatic changes
Capillary refill delay
Peripheral perfusion
Abdominal and focused systems
Abdominal exam
Tenderness distribution
Guarding
Rebound
Distension
Bowel sounds
Neuro and cardiopulmonary
Mental status
Focal deficits
Lung exam for aspiration
Heart rhythm irregularity
Skin and temperature exposure
Hot water burn findings
Diaphoresis
Lab Studies
Core ED labs
Basic evaluation
CBC
Electrolytes
Creatinine
Glucose
Magnesium
Phosphate
Targeted labs by differential
Lipase
Liver enzymes
Pregnancy test
Urinalysis
Serum ketones if suspected ketoacidosis
Interpretation pearls and pitfalls
Common abnormalities in severe vomiting
Hypokalemia
Hypochloremic metabolic alkalosis
Elevated creatinine from dehydration
Alternative physiology patterns
Metabolic acidosis with ketones in starvation or DKA
Lactic elevation in shock
Cannabinoid testing limitations
Urine THC persistence for days to weeks
Not confirmatory for CHS
Imaging
Scoring Systems
Imaging decision logic framework
Low imaging yield when classic CHS pattern and benign exam
Imaging favored when alarm features present
Imaging favored when first episode or atypical features
MRI
Neuro imaging considerations
MRI brain when persistent vomiting with focal neuro deficits
MRI brain when concern for posterior fossa pathology
CT
Abdomen pelvis CT considerations
CT when obstruction concern
CT when peritoneal signs present
CT when severe focal tenderness
CT when new onset vomiting without prior cyclic pattern
Contrast cautions
Acute kidney injury risk with dehydration
Allergy history
Ultrasound
RUQ ultrasound
RUQ pain or abnormal liver enzymes
Suspected cholecystitis or biliary colic
Pelvic ultrasound
Pregnancy related pain or bleeding
Concern for ectopic pregnancy
Special Tests
Bedside diagnostics
Bedside assessment adjuncts
Point of care glucose
Orthostatic vitals
Bladder scan if urinary retention concern
Pregnancy focused
Point of care pregnancy test
Ectopic risk assessment
Substance and tox considerations
Toxicology adjuncts
Acetaminophen level when overdose concern
Salicylate level when mixed ingestion concern
ECG
Indications and safety monitoring
ECG indications in vomiting presentations
Electrolyte abnormalities
Syncope or palpitations
QT prolonging antiemetic use
QT related risk mitigation
Baseline QTc prior to haloperidol or droperidol when feasible
Repeat ECG after treatment if QTc prolonged or symptoms develop
Assessment
Working diagnosis and severity
Cannabis hyperemesis syndrome
Cannabis use with other cannabis induced disorder (F12.288)
Nausea with vomiting (R11.2)
Vomiting unspecified (R11.10)
Classic features
Chronic cannabis exposure
Hot shower relief
Recurrent stereotyped episodes
Severity stratification
Mild
Able to tolerate some oral fluids
No significant electrolyte derangement
Moderate
Persistent vomiting
Requires IV fluids
Correctable electrolyte derangement
Severe
Hemodynamic instability
Acute kidney injury
Refractory symptoms despite ED therapy
QTc prolongation limiting antiemetic options
Diagnostic uncertainty and alternatives
Alternative diagnoses requiring exclusion
Pregnancy related vomiting
Pancreatitis
Obstruction
DKA or starvation ketosis
CNS pathology with neuro findings
Plan
Approach to the critical patient
First 5 minutes workflow
Airway and aspiration risk
Suction readiness
Lateral positioning if actively vomiting
Monitoring
Continuous pulse oximetry
Cardiac monitor if severe electrolyte derangement or QT risk
IV access and fluids
Two IVs if shock or severe dehydration
Isotonic crystalloid bolus if hypovolemia
Time critical tests
Point of care glucose early
Pregnancy test early in patients with pregnancy potential
Reassessment loop
Symptom reassessment every 30 to 60 minutes while in ED
Repeat vitals after fluids and antiemetics
Repeat electrolytes after repletion if severe derangements
Escalate level of care for persistent instability
Fluids and electrolyte correction
Volume resuscitation
Normal saline or balanced crystalloid IV
Bolus 10 to 20 mL per kg for significant dehydration local protocol dependent
Maintenance IV fluids after bolus based on ongoing losses
Potassium repletion
If potassium less than 3.0 mmol per L IV replacement with cardiac monitoring
Typical IV potassium chloride 10 to 20 mEq per hour
Avoid dextrose containing fluids if worsening hypokalemia risk
Magnesium repletion
If magnesium low or QTc prolonged
Magnesium sulfate IV 1 to 2 g
Metabolic derangements
If ketoacidosis suspected treat per DKA or starvation ketosis pathway
If severe alkalosis and ongoing vomiting prioritize volume and chloride repletion
Antiemetics and symptom control
Standard antiemetics
Ondansetron IV 4 mg
Repeat dosing based on response local protocol dependent
QTc caution in prolonged QT
Dopamine antagonists for CHS
Haloperidol IV 0.05 mg per kg
Typical adult dose 2.5 to 5 mg
Dystonia risk
Diphenhydramine IV 25 to 50 mg for dystonia treatment
QTc and torsades risk
Avoid if markedly prolonged QTc or severe hypokalemia until corrected
Droperidol option where available
Droperidol IV 0.625 to 1.25 mg
QTc monitoring local protocol dependent
Sedation monitoring
Topical capsaicin
Capsaicin 0.025 percent to 0.1 percent topical to abdomen or arms
Application with gloves
Burning sensation counseling and skin irritation monitoring
Benzodiazepines adjunct
Lorazepam IV 0.5 to 1 mg for anxiety and refractory nausea
Avoid oversedation especially with co ingestion
Pain management cautions
Avoid opioids when possible
Acetaminophen if mild pain and no liver injury concern
Cannabis cessation pathway
Definitive management
Cannabis cessation as key intervention
Symptom resolution timeline days to weeks after cessation
Withdrawal management
Sleep disturbance
Irritability
Nausea during withdrawal
Referral and supports
Substance use counseling referral
Primary care follow up for cessation plan
Disposition
Level of care criteria
ICU criteria
Shock requiring vasopressors
Severe electrolyte derangement with arrhythmia
Refractory vomiting with airway risk
Severe metabolic derangement requiring intensive monitoring
Inpatient admission criteria
Acute kidney injury not improving with fluids
Persistent electrolyte abnormalities requiring IV replacement
Refractory symptoms after ED therapy
Inability to tolerate oral intake after observation
Complications
Aspiration pneumonitis
GI bleeding
Observation pathway criteria
Moderate symptoms responding to ED therapy but not ready for discharge
Need for repeat labs after repletion
Need for serial ECG for QTc risk
Discharge criteria
Vital signs stable
Pain controlled
Tolerating oral fluids
Electrolytes corrected or mild and stable
Reliable follow up and cessation counseling plan
Follow up timing
Outpatient follow up
Primary care within 3 to 7 days
Substance use services within 1 to 2 weeks
GI referral if atypical course or ongoing symptoms despite cessation
Discharge Instructions
Copy discharge instructions
Diagnosis summary
Your symptoms are consistent with cannabis related recurrent vomiting
The most effective treatment is stopping cannabis completely
Medications
Take nausea medicine exactly as prescribed
Do not take extra doses of nausea medicine without medical advice
Avoid alcohol and sedating drugs while using prescribed anti nausea medications
Hydration and diet
Small frequent sips of oral rehydration fluids
Advance diet slowly as tolerated
Activity
Avoid driving if sedated from medications
Avoid prolonged hot showers due to burn and dehydration risk
Return to ED now if
You cannot keep down fluids for 12 hours
You have severe abdominal pain
You have blood in vomit or black stools
You faint or feel like you will faint
You have chest pain or trouble breathing
You have fever 38.0 C or higher
Follow up
Primary care follow up within 3 to 7 days
Substance use support follow up within 1 to 2 weeks
References
Key guidelines and evidence
Reference list
American Gastroenterological Association clinical practice update on cannabinoid hyperemesis syndrome 2024
Rome IV functional gastrointestinal disorders criteria 2016
ACEP clinical policy on nausea and vomiting symptom management local protocol dependent
Randomized trial evidence on haloperidol for cannabis hyperemesis syndrome 2020
Review evidence on topical capsaicin for cannabis hyperemesis syndrome 2020
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.