With widespread cannabis legalization across the country, a rare and painful disorder is emerging. Known as cannabinoid hyperemesis syndrome (CHS), this gastrointestinal condition is sending many long-term marijuana users to emergency rooms, suffering from episodes of excruciating pain, severe vomiting, and even tooth loss.

CHS is a relatively new term for the acute reaction to cannabis use, characterized by severe bouts of nausea, abdominal pain, and vomiting. Patients often scream and vomit due to the pain, a phenomenon referred to as 'scromiting.' Many patients with the symptoms resort to hot showers or baths, which can lead to compulsive bathing.

Severe vomiting from the CHS can lead to erosion of teeth enamel and teeth loss. The patients often experience low levels of essential blood salts, including chloride, potassium, sodium, and bicarbonate. The condition may also result in dehydration, acute kidney injury, and complications such as kidney failure, seizures, and abnormal heart rhythms. Rarely severe complications can be fatal.

The syndrome is diagnosed in patients who use cannabis more than four days a week for over a year and report at least three episodes of symptoms per year, each lasting more than a week.

However, not all long-term marijuana users develop CHS. For those who do, the effects can be puzzling, as marijuana is often used to prevent nausea and vomiting, particularly in chemotherapy patients. Experts believe this contradiction occurs because cannabis affects the brain and digestive system in opposite ways. Initially, the brain responds by reducing nausea, but with repeated use, its receptors may stop functioning the same way, leading to the severe nausea and vomiting associated with CHS.

Although the exact prevalence is unknown, based on reported cases in emergency departments, CHS is estimated to affect around 2.75 million people in the U.S. annually. The incidence of CHS has doubled from 2017 to 2021, with emergency department visits for the condition increasing in both the U.S. and Canada. The disorder is most common among males aged 16 to 34 years.

"The rise in CHS coincides with legalization of recreational cannabis and increases in delta-9-tetrahydrocannabinol (THC) concentration in cannabis products," a recent study report stated.

The first step in treatment is to stop cannabis use. Although the symptoms and side effects may persist after stopping cannabis, they will disappear in a few weeks. Those seeking emergency care will receive medications to reduce dehydration and relieve pain and vomiting. Short-term use of certain antipsychotic and antianxiety drugs may also help patients recover.

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