Description

• Cannabinoid hyperemesis syndrome (CHS) is defined by cyclic nausea, vomiting, and abdominal pain typically relieved by hot showers or baths in the setting of chronic cannabis use.
• Easily misdiagnosed as cyclic vomiting syndrome. Patients have chronic cannabis use history, and symptoms may not be relieved by conventional antiemetics or analgesics.
• Patients often remain undiagnosed for a substantial time.

Epidemiology

Incidence

• Cannabis use has been increasing with the legalization of medical and recreational use. In 2017, 30.5 million Americans reported current cannabis use (1).
• CHS and other cannabis-related emergency department visits in areas where cannabis has been legalized have increased significantly.

Prevalence
Up to 2.75 million people in the United States may suffer from CHS (2).

Etiology and Pathophysiology

• The pathophysiology remains unknown, but there have been multiple proposed mechanisms.
• Cannabinoids such as cannabidiol (CBD) at high doses may be proemetic, whereas low doses are antiemetic (3).
• Cannabinoid receptors CB1 and CB2 are located in the CNS and GI system. CB1 receptor activity is thought to be responsible for the effects on cognition, memory, nausea, and vomiting.
• CHS may be due to desensitization or downregulation of CB1 receptors (4).
• G-protein coupled tissue receptors called TRPV1 that are located in the area postrema of the medulla, gastric enteric nerves, and vagal nerves. Prolonged exposure to cannabinoids inactivate TRPV1, which may result in nausea, abdominal pain, and altered gastric motility.
• Nociceptive stimulation through heat (hot showers) or topical capsaicin may relieve symptoms through activation of TRPV1 (5).

Genetics
Cannabis use disorder has a potential hereditary component; the genetic contribution may be greater in adolescents than adults.

Risk Factors

Risk factors for cannabis use disorder include age (highest in 18 to 25 years), male sex, lower socioeconomic status, comorbid psychiatric disorders, and other substance use.

General Prevention

Cannabis cessation or avoidance

Commonly Associated Conditions

• Substance use disorders
• Delayed gastric emptying