Why do hot showers relieve this teen’s nausea? | Medical Mystery

An 18-year-old woman came to see her primary care pediatrician while she was home from college during Thanksgiving break. Her doctor, who’d known her since she was a baby, was delighted to see her. But when she inquired how college was going, the young woman’s face fell.

Things weren’t going well. Moving away from home to a college out of state was more challenging than the teen had expected. It was difficult to make friends because many of the other students knew each other from high schools in the area. She had rushed a sorority but hadn’t felt like she fit with any of them, and ultimately she hadn’t been selected. Beyond that, she had planned to study law, but she was finding her coursework overwhelming. She became anxious whenever she had a paper due and would leave it to the last minute, only to pull all-nighters right before the deadline. To make matters worse, she was missing a lot of class because every couple of weeks she would have a day of severe nausea and vomiting. Some days, she threw up more than 10 times.

Her doctor knew this intelligent young woman likely had a few ideas about what might be causing her symptoms. The teen admitted that her biggest worry was that she may be pregnant, and she was vomiting because of morning sickness. One of the few people she was able to turn to in her new environment was her high school boyfriend, who frequently drove over to visit her. They’d had unprotected sex several times. The young woman also admitted that she wondered whether her nausea was related to her chronic stress and anxiety. She had started vaping marijuana almost daily as a junior in high school to cope with her stress.

The doctor asked whether anyone else in her dormitory was having the same symptoms. Viruses that cause vomiting and diarrhea like norovirus can spread quickly where people are living in close quarters. The doctor also knew that the young woman had suffered from migraines in the past, which can come with nausea. So the doctor asked about other symptoms, but the patient denied any abdominal pain, diarrhea, or headaches.

The clue to the diagnosis came when the doctor asked what made the nausea better. The teen told her that the only thing that worked every single time was taking a shower—the hotter the better.

There were many possible culprits that could have been the cause of this young woman’s nausea, but the hot showers clued her doctor in to the diagnosis: Cannabis hyperemesis syndrome. Cannabis hyperemesis is still incompletely understood, but research suggests that the use of marijuana can cause a decrease in anti-vomiting pathways in the brain. It is not known why hot showers make the nausea better but this is a classic finding in people with cannabis hyperemesis.

The doctor also ordered tests for pregnancy and sexually transmitted infections. All the results were negative, to the young woman’s relief.

But the ultimate cure? Stopping cannabis altogether. The teen asked whether she could just use a little less marijuana, but her doctor explained the only proven way to cure the nausea was to stop completely. The doctor also helped the teen find a healthcare provider closer to her college who could help her stop cannabis safely and effectively.

Cannabis hyperemesis syndrome will not affect everyone who smokes marijuana. But though many people think marijuana is benign, the truth is that use of any amount can cause serious health problems, especially in adolescents. Be sure to talk to your teens about the associated risks of drug use, and consult with a medical professional if needed.

Samantha Starkey is a second-year pediatric resident and Hayley Goldner is a pediatrician in the adolescent medicine department at Nemours Children’s Hospital, Delaware.