Background
- Occurs in the context of at least weekly cannabis consumption, for at least 1 year - NOT an intoxication effect from a single large ingestion
- Episode timing and severity does not correlate with amount of cannabis consumed, and patient may find cannabis temporarily relieves symptoms during an episode
Phase 1: Prodromal
- Can last months to years
- Characterised by nausea, abdominal discomfort, emetophobia
- Symptomatic on one or more days of the week
Phase 2: Hyper-emetic
- Intractable vomiting, abdominal pain, weight loss
- Symptoms present on waking up
- Episodes lasting several days, with weeks-months of remission between
- Patients report improvement in symptoms in hot showers or baths (compulsive use of same)
Phase 3: Recovery
- Occurs when cannabis consumption is stopped
- Symptoms may improve within 24-48 hrs, with return of symptoms if cannabis consumed again
Approach
Diagnosis is based on clinical history:
- Cyclical pattern of vomiting:
- Episodes last <7 consecutive days
- Can have asymptomatic periods of weeks to months between episodes
- Prolonged cannabis use:
- >Once per week for >1 year
- Exclusion of alternative diagnoses:
- CHS should not present with abnormal vital signs, abnormal bowel movements, focal abdominal pain, peritonitis or jaundice
Investigations
Evaluate for complications / DDx.
- U&E - Electrolytes, AKI
- Metabolic acidosis/alkalosis
- Glucose and Ketones
- Pregnancy test
- ECG - QTc, (before admin. of antiemetics)
Differential Dx
- Gastritis / GERD / PUD
- Intra abdominal pathology (appendicitis, diverticulitis, sigmoid volvulus, biliary colic, pancreatitis, etc)
- Infection
- Pregnancy
- Ovarian torsion
- Malig. (intracranial, abdominal)
Red flags
- ↓Wt (esp. age >50 yrs)
- Abdominal mass
- Change in bowel habit
- Anaemia
- LFT abnormalities
Management
- The only definitive treatment for CHS is cessation of cannabis consumption.
- Management can be challenging, as CHS is often resistant to traditional antiemetics (ondansetron, antihistamines), however normal treatment of nausea and vomiting can be trialled in the first instance.
- Avoid metoclopramide (↑ risk of EPS if haloperidol co-prescribed).
Haloperidol IM 0.05mg/kg (max 5mg)
- Olanzapine if allergy to haloperidol, ↑QTc or Hx of extrapyramidal sympt. with haloperidol/PD/LBD
Capsaicin 0.1% cream TOP - applied to abdomen
Consider:
- Hot Bath/Shower
- Benzodiazepines - Lorazepam 1-2mg IV
- Limited evidence for TCAs, levetiracetam, PPIs and Β-blockers
Follow up
- Cannabis abstinence is the only long term treatment for CHS
- GP follow up, sign posting advice, or referral to local supports may improve successful cessation
- Reasonable to suggest non-emergent OGD as outpatient if newly Dx/not previously Ix