Does Cannabinoid Hyperemesis Syndrome Cause Diarrhea?
No, diarrhea is not a characteristic feature of cannabinoid hyperemesis syndrome (CHS). The syndrome is defined by cyclic episodes of nausea, vomiting, and abdominal pain—not diarrhea 1.
Core Clinical Features of CHS
The American Gastroenterological Association defines CHS by three cardinal symptoms 1, 2:
- Stereotypical episodic vomiting (acute onset, duration <1 week, occurring ≥3 times annually)
- Nausea (often severe and intractable)
- Abdominal pain
Notably absent from diagnostic criteria is any mention of diarrhea as a presenting or associated symptom 1.
Pathophysiological Mechanism Explains Absence of Diarrhea
The pathophysiology of CHS centers on CB1 receptor dysregulation in the dorsal vagal complex, which controls emesis, not intestinal motility patterns that would produce diarrhea 3. The mechanism involves:
- Loss of negative feedback on the hypothalamic-pituitary-adrenal axis, resulting in increased vagal nerve discharges that trigger vomiting 3
- Peripheral CB1 receptor activation affects gastric motility and emptying, not colonic transit acceleration 1, 3
- TRPV1 receptor binding affects vagus nerve function related to emesis pathways 3
Important Clinical Distinction: Cannabis Withdrawal Syndrome
If diarrhea is present, consider cannabis withdrawal syndrome (CWS) instead of CHS. This is a critical diagnostic pitfall 4:
- CWS occurs in approximately 47% of regular cannabis users after cessation 4
- Gastrointestinal symptoms including diarrhea are recognized features of CWS 4
- The timing is opposite: CWS symptoms begin 24-48 hours after stopping cannabis, while CHS occurs during active chronic use 4
For diarrhea in CWS, the American College of Gastroenterology recommends standard antidiarrheal agents such as loperamide 4.
Common Diagnostic Pitfall
CHS is frequently misdiagnosed due to limited clinician awareness, leading to extensive unnecessary testing 2. When evaluating a patient with vomiting and diarrhea who uses cannabis:
- First rule out life-threatening conditions (acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis) 2
- Then distinguish CHS from CWS based on timing relative to cannabis use 4
- If diarrhea is prominent, CHS is unlikely and alternative diagnoses should be pursued
The pathognomonic hot water bathing behavior (present in 44-71% of CHS cases) specifically addresses nausea and vomiting, not diarrhea 2, 4.