In early 2010, actress Chandra Wilson's teenage daughter, Sarina McFarlane, began experiencing never-ending bouts of nausea. Every month the queasiness escalated to the point that, for days, McFarlane could not stop vomiting.
Like clockwork, the vomiting stopped and nausea eased a bit. But when a new month started, the vomiting cycle returned.
The case sounded like an episode straight out of "Grey's Anatomy," where Wilson plays Dr. Miranda Bailey. Wilson said for a year, her daughter's doctors were baffled by the condition.
"She had every kind of scan you could think of, you know, upper GI's and CT scans, and delayed gastric emptying tests, and you know, blood work constantly," Wilson told ABC's local Philadelphia affiliate, WPVI.
After excluding a host of other possible diagnoses, Wilson said her daughter was diagnosed with cyclic vomiting syndrome, or CVS, a neurological disorder characterized by a series of prolonged attacks of severe nausea and vomiting, with no apparent cause.
CVS is also known as abdominal migraines because symptoms usually begin with severe abdominal pain or a migraine headache, followed by episodes of vomiting that can last for hours or even days.
Once an episode is over, the sufferer inexplicably returns to normal health, often with no remnants of the disease.
For most people, vomiting can be a source of relief from an unsettled stomach. But for those who suffer from CVS, initial vomiting only triggers a cycle of more vomiting.
While a definite cause is unknown, some researchers point to a variety of neurological conditions that may be related to CVS. Many experts say CVS may be one variation of a migraine.
"The gut contains a large amount of serotonin, perhaps more than the brain itself, so that represents a curious linkage between migraine, which also involves dynamics with serotonin," said Dr. Joel Saper, founder and director of the Michigan Headache and Neurological Institute.
According to researchers, for some, an intense headache or a condition known as an abdominal migraine may signal the onset of a vomiting episode. And many diagnosed with CVS have shown a family history of migraine headaches.
"The direction research is headed, we'd say it's highly likely that there is genetic connection between migraines and CVS," said Kathleen Adams, president and co-founder of the Cyclic Vomiting Syndrome Association.
Adam says the association's scientific board is working to change the CVS's diagnostic code from its current classification as a gastrointestinal illness to a form of migraine.
Search Continues for Cause and Treatment of Mystery Illness
While the actual number of cases is unknown because of sparse research on the syndrome, estimates indicate that CVS may not be as rare as many believe. Rather, according to the Cyclic Vomiting Syndrome Association, more often it is misdiagnosed. Surveys that have been conducted on the condition suggest that as many as 2 percent of children worldwide may suffer from CVS.
Initially identified as a pediatric disease and believed that children would outgrow the disorder, researchers now say it can persist into adulthood and even appear in adults for the first time.
Natalie Robertson's most distinct memory of her first week as a freshman at Chico State University in California was enduring daylong episodes of uncontrollable vomiting.
"She would throw up in the bushes on the way to class," said Lynne Bussey, Robertson's mother. "Sometimes she would have to run out the door in the middle of class."
Initially, some thought Robertson, who was 18 at the time, was hung over from a night of heavy drinking. Others believed she was bulimic. And although Robertson claimed her vomiting episodes would come without warning, many did not believe her mystery illness, she said. Teachers warned Robertson that excessive absences from class put her at risk of failing.
"I've had to drop classes because [my illness] has been too overwhelming," Robertson said.
Many doctors diagnosed Robertson with the stomach flu or food poisoning, Bussey said. Yet, Robertson's symptoms persisted for two years until she was diagnosed with CVS.
Unlike with bulimia, which is a cycle of binge eating followed by purging, those with CVS have repeated episodes of vomiting that can begin and continue on an empty stomach. Also, CVS episodes are induced by overwhelming nausea, while individuals with bulimia often vomit without feeling nauseated.
Robertson has been hospitalized more than 60 times in the last decade. Like clockwork, Robertson woke up with a headache or nausea; oftentimes she started her day after she vomits. Her symptoms eased in the evening, but recurred early the following morning.
Bussey said she has connected with at least 15 others in Butte County who have the disease and also claim that they are not believed.
Dr. David Fleisher, an associate professor of children's health at the University of Missouri who has treated Robinson and more than 400 other patients with CVS, said he understands why many with the disorder are met with skepticism from others -- doctors included. The primary reason, he said, is that many physicians may not have heard of the disease.
"With functional disorders like CVS, the only way to diagnose it is to get a patient's history of symptoms," said Fleisher. "Not many physicians know the clinical pattern of CVS, so it's hard for patients to get the recognition or care they need."
CVS is often mistaken for other disorders including urinary tract infection, appendicitis and brain tumors seen in MRI scans, Fleisher wrote in a 1993 article in the Journal of Pediatric Gastroenterology and Nutrition.
In a 2002 issue of Contemporary Pediatrics, Dr. B.U.K. Li, director of the Cyclic Vomiting Program at Children's Hospital in Milwaukee, Wis., and one of the world's leading experts on CVS, blamed the on-again, off-again symptoms for difficulties in understanding the disease.
"Between episodes, the child with CVS is asymptomatic and appears so normal that the history of repetitive bouts of relentless vomiting and dehydration can be difficult to believe," he wrote.
According to Fleisher, some behaviors by individuals with CVS during an episode may also mislead doctors.
Bussey said when her daughter has nothing left in her stomach to vomit, she drinks water to induce vomiting, which can make her feel better, which, according to Fleisher, is an action some doctors may interpret as bulimia. Otherwise, the violent reflux and bile may cause her daughter to burn her esophagus and stomach lining, Bussey said.
At times, an attack can send Robertson into a state of conscious coma. Robertson can understand what is going on around her, but is unable to respond to others.
"Their mental state is altered so they can hear what others are saying, but they are unable to answer," said Fleisher. "So commonly it can be seen as a symptom of drug abuse or being drunk."
Currently there are no diagnostic tests for CVS. Though medications are available to alleviate the pain experienced during a vomiting episode, there is no standard treatment for the condition.
According to Fleisher, sometimes the only way physicians can control CVS symptoms during an attack is to sedate the patient.
"Emotions promote nausea and CVS," said Fleisher. "When doctors put them to sleep, the vomiting stops immediately and they are numb to their misery."
While a migraine may by one explanation for the onset of symptoms, Fleisher said many episodes are triggered by emotional stress or excitement.
"Big events, such as final exams or a special occasion brings on an episode," Bussey said.
Worse, according to Fleisher, the anxiety experienced by some CVS sufferers in between episodes may cause some to continually experience symptoms of CVS, called dyspeptic nausea.
"CVS is generally not a fatal disease, but it can get complicated if not recognized or handled right," he said.
Robertson manages her condition through a combination of medications aimed at quelling her pain, nausea and anxiety. But even this has not completely stopped the episodes or symptoms, Robertson said.
That is, until February 2010, when Robertson found out she was pregnant.
At first, Bussey said, they were "dumb-founded, terrified, and panicked" for the baby's safety, and at the idea of Robertson enduring a pregnancy through her symptoms.
Her doctors were unable to explain why her pregnancy quelled many of her symptoms.
"Her illness began to improve dramatically, she has had no hospitalizations since, and delivered a healthy baby boy in December," said Bussey. "I have a normal daughter for the first time in 10 years."
With little awareness and limited research on CVS, Bussey said she fears sufferers like her daughter may never understand what brings on CVS and how to treat the condition. Although Bussey says things are looking up her daughter's condition, she says they are not sure what to expect in the future. For now, she says, they will continue to follow up with her doctors.
For more information on CVS, visit http://www.cvsaonline.org.