AURORA, Colo. -- A little-known syndrome connected to heavy marijuana use is on the rise in Colorado, according to doctors.

Cannabinoid hyperemesis syndrome, or CHS, was first described a decade ago, but researchers in Colorado said they are seeing double the number of cases since marijuana was legalized.

"The science behind it is not clear. We’re just starting to recognize that it even exists," said Dr. Kennon Heard, an emergency physician at the University of Colorado Hospital in Aurora. "The most likely cause is people using marijuana frequently and in high doses have changes in the receptors in their body, and those receptors become dysregulated in some way, and it starts causing pain."

The syndrome usually involves severe abdominal pain, vomiting and nausea.

"I thought I was dying. My kidneys were completely shutting down," said Lance Crowder, speaking by webcam from Indiana, where it took doctors more than two years to diagnose the condition that left him repeatedly in the hospital.

One clue doctors had to a diagnosis was what he had been doing to make himself feel better.

"The only way to warm my body would be to get in a hot shower, and it seemed to help with the nausea, too," said Crowder.

Doctors don't know exactly why, but patients with CHS often turn to hot showers or baths to relieve their symptoms.

Dr. Heard is studying the rise in the syndrome since legalization and found that since 2009, the number of cases at the University of Colorado Hospital and Denver Health has almost doubled.

"We’re still seeing this throughout emergency rooms in Colorado. When I talk to my colleagues, they’re seeing this on a daily to weekly basis," said Heart, who said patients are given IV fluids and medication to resolve the vomiting and help with the pain. "But the treatment is really to stop using marijuana, or at least to cut back severely, and that’s really the only way to make it better."

Crowder said once he quit smoking, his symptoms went away, and while he is still pro-pot, he wants people to be aware of the risks.

"I was a daily user: breakfast, lunch, dinner. I would smoke heavily on the weekends — I just abused it," said Crowder. "I really believe it’s like everything else in this world, and if you habitually abuse it it’s going to have health effects on your body."

No one knows exactly how many people have CHS, and doctors say it is difficult to diagnose, in part, because many patients don't want to tell their doctors they use marijuana.

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