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Cyclic Vomiting Syndrome (CVS)

B U.K. Li, M.D.
Director of Pediatric Gastroenterology
Children's Memorial Hospital
Chicago, IL

What is cyclic vomiting syndrome?

Cyclic vomiting syndrome, or CVS, is a disorder characterized by recurrent and severe episodes of vomiting. Because its cause is unknown and there is not a laboratory test for it, this condition is considered a syndrome, rather than a disease.


What causes cyclic vomiting syndrome?

Currently, there is no known cause of CVS. The main theory to its cause is that CVS may be related to migraine headaches. It also is suspected that it is a "brain-gut" disorder in which a trigger within the brain signals the gut to begin vomiting. Other theories to its cause also are being investigated (see the What research is being done? section).


Who gets cyclic vomiting syndrome?

Children between the ages of 4 and 11 years most often are affected with CVS; however, newborns and adults can develop it. Slightly more girls than boys experience this syndrome.


What are the common findings?

The main symptom is relentless vomiting, often three to six times per hour at the peak of the worst episode. Many children state that the unremitting nausea is the worst symptom because they do not experience momentary relief from the vomiting.

Other common gastrointestinal symptoms include loss of appetite, nausea, dry heaving, and abdominal pain. Diarrhea occurs in one-third of the children who have CVS. Common general symptoms include paleness and listlessness.

Fever occurs in one-third of the children. Typical symptoms of migraine headaches and sensitivity to lights occur in less than one-half of those children who experience CVS. During these episodes, children are sicker than if they had the stomach flu.

There is a timing pattern to this syndrome. The episodes most often occur in the early morning hours, between 2 a.m. and 4 a.m., or upon awakening; however, they can occur at any time of the day.

The term "cyclic" refers to the predictable period between episodes. However, only one-half of the children have predictable intervals, most commonly every two or four weeks, and one-half of the children have attacks that occur at irregular intervals. Episodes rarely occur more than twice a week, and they can be as infrequent as 6 to 12 months apart.

The episodes can be triggered by various life events. The most common include viral infections, such as colds and sinusitis, and psychological stress that occurs at school or even during holidays, vacations, and birthdays.

Dietary cheese, chocolate and monosodium glutamate, long car rides, physical exhaustion, and allergies also trigger cause it. In teenage girls, menstruation can precipitate episodes.

Fortunately, CVS usually resolves itself as the child enters adolescence; however, it can persist into adulthood. In some cases, it begins in adulthood. For those children in whom it stops completely, one-third of them develop typical migraine headaches.


How is cyclic vomiting syndrome diagnosed?

A test to diagnose CVS is not available. At the first international symposium on CVS in 1994, an international committee developed its diagnostic criteria.

The three main criteria included are:

  • Recurrent, severe episodes of vomiting
  • Normal health between episodes
  • No cause of vomiting found on testing

The four supportive criteria included:

  • Each episode is similar to the other episodes
  • Episodes resolve if they are left untreated
  • Associated symptoms of nausea, abdominal pain, headache, motion sickness, and sensitivity to lights
  • Associated signs of fever, paleness, diarrhea, dehydration, and excess salivation

Most often, cyclic vomiting syndrome is confused with stomach flu or viral gastroenteritis. The symptoms of vomiting, when combined with fever and diarrhea, can be indistinguishable from those with the stomach flu. In addition, the physician often does not appreciate the overall pattern of recurrence.

Several serious disorders can be confused with CVS, including malrotation with volvulus (twisted and kinked small intestine), brain tumors, acute hydronephrosis (swelling of the kidneys), Addison's disease (lack of cortisol hormone), various metabolic disorders (problems processing nutrition or waste products), and psychological disturbances.

Although a diagnostic test for CVS is not available, laboratory testing (blood and urine), x-rays (intestines, kidney, and brain), and endoscopic (stomach) testing can be used to exclude the most serious disorders. For example, if a twisted, or malrotated, intestine appears to be the cause of the vomiting, a child would be diagnosed with malrotation, not CVS.

A family physician, a pediatrician, a pediatric gastroenterologist, or a pediatric neurologist may arrange the specific tests. The amount of testing that is requested is up to the doctor's best judgment.



How is cyclic vomiting syndrome treated?

Because there have not been definitive studies on treatment, there is not a standard recommended therapy for CVS. However, there are effective medications. Five approaches are used in treating CVS, including care during the episode itself, medicines to break the attack once it starts, avoidance of known triggers, medicines used to prevent the next episode, and family support.

The first two treatment approaches are discussed in this section. The second two treatment approaches are discussed in the How can cyclic vomiting syndrome be prevented? section. The final treatment approach is discussed in the Links to other information section.

Care during the episode

Intravenous sugar (dextrose) and fluids often help to correct dehydration. Although the pain can be severe, it usually does not require narcotic drugs. Although the vomiting can be lessened by medications, the nausea often persists. Sometimes, sedation with diphenhydramine, lorazepam, or chlorpromazine is the only way to lessen the nausea.

Medicines to break the attack

Medications used to break an attack are given at the start of the episode. They include anti-vomiting medicines, such as ondansetron and granisetron, which are administered intravenously, and promethazine and prochlorperazine, which are administered rectally or by shot.

Although widely used, the latter two drugs are not very effective in treating CVS. Anti-migraine medications can also be used. Oral agents, such as Midrin, are often ineffective because they are expelled by vomiting. Oral and nasal sumatriptan have been used in a few children with CVS, but they have not been studied for proper dosage, safety, or effectiveness.


What are the complications?

Fortunately, there does not appear to be serious long-term complications associated with CVS. However, despite being sick only intermittently, children miss 2 to 4 weeks of school and require intravenous fluids at the hospital 50% of the time. Unfortunately, the correct diagnosis of CVS typically is not made for two and one-half years.


How can cyclic vomiting syndrome be prevented?

Avoidance of known triggers

In a few cases, known triggers of CVS can be avoided to prevent episodes, e.g., having the parents eliminate chocolate and/or cheese from the child's diet.

Medicines used to prevent episodes

To prevent episodes of CVS, migraine (propranolol, cyproheptadine, and amitriptyline), seizure (phenobarbital and phenytoin), or stomach (ranitidine, erythromycin, and cisapride) medications can be taken daily. Most of these medications have been studied in children, and they are widely used.

A physician should choose the appropriate medication, with the least amount of side effects, for a child. Although none of the medications are 100% effective, most of them reduce the severity of CVS in half of the children.


What research is being done?

The cause of CVS is unknown; it is not known whether it is a disorder of the brain, the gut, or another organ. There are several new theories about how CVS is caused, and research is being conducted on each theory. Many children with CVS may have an underlying, but atypical, migraine disorder that primarily causes vomiting and abdominal pain rather than headache.

Some children are thought to have a mitochondrial disorder (energy factory for each cell) that affects respiratory chain or fatty acid metabolism. Other children are thought to have a disorder of the hypothalamus (brain thermostat) that produces excess stress hormones.

Some children are thought to have a dysmotility (pumping disorder) of the intestinal tract. New medications to treat both vomiting and stress-induced disorders are being developed by pharmaceutical companies.


Links to other information?

Family support

Often, parents are stressed by this repetitive, unpredictable, and disruptive illness. They watch their child become ill and hospitalized, they do not know what is causing the illness, they miss work, and physicians often do not take the recurrent illness seriously. The parents and the child can benefit from the support of other families with the same illness.

Mailing Address:

Cyclic Vomiting Syndrome Association

Ms. Debra Waites, Administrator

3585 Cedar Hill Rd, NW

Canal Winchester, Ohio 43110

Phone: (614) 837-2586

Web Site:




Fleisher DR, Matar M. The cyclic vomiting syndrome: a report of 71 cases and literature review. J Pediatr Gastroenterol Nutr 1993 Nov;17(4):361-9.

Li BUK, ed. Proceedings of the International Symposium on Cyclic Vomiting Syndrome J Pediatr Gastroenterol Nutr 1995;21(Suppl.):S1-S62.

Li BUK, Issenman RM, Sarna SK, eds. Proceedings of the 2nd International Symposium on Cyclic Vomiting Syndrome Dig Dis Sci 1999;44(Suppl.):1S-120S.

Li BUK, Murray RD, Heitlinger LA, Robbins JL, Hayes JR. Heterogeneity of diagnoses presenting as cyclic vomiting. Pediatrics 1998 Sep;102(3):583-7.

Li BUK, Murray RD, Heitlinger LA, Robbins JL, Hayes JR. Is cyclic vomiting syndrome related to migraine? J Pediatr 1999 May;134(5):567-72.

Author's Biography

Fleisher DR, Matar M. The cyclic vomiting syndrome: a report of 71 cases and literature review. J Pediatr Gastroenterol Nutr 1993 Nov;17(4):361-9.

Li BUK, ed. Proceedings of the International Symposium on Cyclic Vomiting Syndrome J Pediatr Gastroenterol Nutr 1995;21(Suppl.):S1-S62.

Li BUK, Issenman RM, Sarna SK, eds. Proceedings of the 2nd International Symposium on Cyclic Vomiting Syndrome Dig Dis Sci 1999;44(Suppl.):1S-120S.

Li BUK, Murray RD, Heitlinger LA, Robbins JL, Hayes JR. Heterogeneity of diagnoses presenting as cyclic vomiting. Pediatrics 1998 Sep;102(3):583-7.

About the Author

Dr. Li is the Director of Gastroenterology at Children's Memorial Hospital in Chicago, IL. He is Professor of Pediatrics at Northwestern University. His primary research interests are in Cyclic Vomiting Syndrome and outcomes in H. Pylori Gastritis. He is a fitness buff and a soccer dad on the side.

Copyright 2012 B U.K. Li, M.D., All Rights Reserved

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