First described in 1882, cyclic vomiting syndrome (CVS) is a rare idiopathic disorder characterized by recurring periods of vomiting in an otherwise normal child. The word, idiopathic, means that the origin of the disorder is unknown. The syndrome is sometimes called abdominal migraine because it may be caused by some of the same mechanisms in the central nervous system that cause migraine headaches.
Description
Children with cyclic vomiting syndrome have bouts of severe nausea and vomiting that may last for hours or days. In some cases the vomiting is so severe that the child is unable to go to school for several days. The episodes alternate with periods of normal digestive functioning.
The bouts of vomiting that characterize CVS usually begin at the same time of day as previous episodes, last about the same length of time, and have the same symptoms. The most common pattern is severe nausea and vomiting that begins late at night or early in the morning. The child may vomit as often as six to 12 times an hour over a period of one to five days, although cases have been reported in which the episode lasts for ten days. The vomited material may contain blood or bile as well as mucus or watery fluid.
In addition to the vomiting, the child may have a headache, low-grade fever, dizziness, pain in the abdomen, heavy drooling, and diarrhea. Some children also become unusually sensitive to light, while others may be unable to walk or talk.
Demographics
Children between the ages of three and seven years are most susceptible to CVS, although it can appear at any time from infancy to adulthood. The average age of patients at onset is 5.2 years, but CVS has been diagnosed in patients as old as 73.
The frequency of cyclic vomiting syndrome in the general population is not known for certain as of the early 2000s, but it is thought that the disorder is probably underdiagnosed because other diseases and disorders can also cause periods of acute nausea and vomiting. Some researchers think that as many as one child in 50 may have CVS.
CVS appears to affect all races and ethnic groups equally. The female-to-male ratio has been reported as 11 to nine.
Causes
The cause of CVS is as of 2004 a mystery. Similarities to migraine suggest a common cause, but no firm evidence has been found. It is known, however, that 82 percent of patients with CVS have a family history of migraine compared to 14 percent of control subjects. Patients can usually identify some factor that precedes an attack. Common triggers of CVS episodes include the following:
In the summer of 2003, two teams of researchers in Italy and the United States reported that some cases of CVS appear to be caused by a DNA mutation that affects the proper functioning of the mitochondria (energy generators) in human cells and that this mutation is inherited from the mother. Further research is needed, however, in order to determine whether other genetic factors are involved in CVS.
Symptoms
Vomiting associated with CVS can be protracted and lead to such complications as dehydration; erosion of tooth enamel leading to tooth decay; unbalanced blood electrolyte levels; and tearing, burning, or bleeding of the esophagus (swallowing tube). Between attacks, however, the child has no sign of any illness.
CVS has four distinct stages or phases:
Prodrome: A warning symptom (or group of symptoms) appears just before an acute attack of an illness. Patients with CVS often feel pain in the abdomen a few minutes or hours before the vomiting starts. Adults with CVS often have anxiety or panic attacks as a prodrome.
Episode phase: The patient is actively nauseated and vomiting and cannot keep down any food or medications given by mouth. He or she may also feel drowsy, dizzy, or exhausted.
Recovery phase: The vomiting stops and the child's normal appetite and level of energy return.
Symptom-free interval.
When to call the doctor
The vomiting and other symptoms associated with CVS are so severe that parents will usually call the doctor during the first episode, before a pattern has been identified. It may take several episodes of the disorder before the parents or the doctor notice a pattern.
Diagnosis
The most important and difficult aspect of diagnosing CVS is to make sure there is not an acute and life-threatening event in progress. So many different diseases can cause vomiting—from bowel obstruction to epilepsy—that an accurate and timely diagnosis is critical. Because there is no way to prove the diagnosis of CVS, the physician must instead disprove every other diagnosis. This process, which is known as a diagnosis of exclusion, can be tedious, expensive, exhausting, and involve almost every system in the body. The first episode of cyclic vomiting syndrome may be diagnosed as stomach flu when nothing more serious turns up. Only after several episodes and several fruitless searches for a cause will a physician normally consider the diagnosis of CVS.
A careful history-taking is critical to making the correct diagnosis of CVS. A family history of migraine, particularly on the mother's side of the family, should alert the doctor to the possibility that the patient has CVS. The doctor may also order blood tests for metabolic screening or imaging studies of the kidneys, gall bladder, small bowel, or sinuses in order to rule out endocrine disorders, gastrointestinal disorders, kidney disease, and chronic sinusitis.
There is no permanent cure for cyclic vomiting syndrome as of the early 2000s. Doctors as of 2004 recommend a combination of several strategies for managing the disorder:
Avoidance of known dietary or stress-related triggers: Such triggers as hot weather or automobile transportation, however, may be difficult or impossible to avoid.
Prophylactic treatment with medications: Prophylactic treatment refers to therapy that is given to prevent a disease. This approach is recommended for children with CVS who have 10 to 12 episodes per year or have episodes of vomiting lasting longer than three days. Several different medications have given good results in small trials. The antimigraine drugs amitriptyline (Elavil) and cyproheptadine (Periactin) performed well for children in one study group. Propranolol (Inderal) is sometimes effective for children with CVS, and erythromycin helped several patients in one study—not because it is an antibiotic but because it irritates the stomach and encourages it to move its contents forward instead of in reverse.
Abortive treatment: Abortive treatment is therapy given to stop an attack of CVS after it has begun. Drugs that have been found to work well as abortive agents are ondansetron (Zofran, an antinausea drug) and sumatriptan (Imitrex, an antimigraine drug). These drugs can be given intravenously, and sumatriptan is also available as a nasal solution.
Supportive care: Supportive care for episodes of CVS includes such antinausea drugs as diphenhydramine (Benadryl) or chlorpromazine (Largactil), and intravenous fluids when necessary.
Another medication that has been reported to be successful in treating children with CVS is dexmedetomidine (Precedex), which was originally developed to sedate patients on respirators in intensive care settings. The researchers found that dexmedetomidine relieved the anxiety as well as the nausea associated with CVS.
Alternative treatment
Constitutional homeopathic medicine can work well in treating CVS because it addresses the person's overall health, not just the treatment of acute symptoms.
Stress management techniques may be helpful for older children or teenagers in preventing episodes of CVS triggered by emotional or psychological stress. These techniques may include the relaxation response developed by Herbert Benson, meditation, and biofeedback.
Weekly outpatient acupuncture treatments are also helpful to some children with CVS.
Nutritional concerns
Avoiding dehydration is the primary nutritional concern during episodes of cyclic vomiting syndrome. In most cases the child will bring up water that is offered during the acute phase of an attack even though he or she may be very thirsty. About 50 percent of children require an intravenous infusion of glucose and water to prevent dehydration.
Some children have a normal appetite for food soon after the vomiting stops, while others may take several days to return to a full diet. Parents should offer the child clear liquids first to prevent dehydration and gradually reintroduce solid foods as the child's appetite improves.
Prognosis
The average duration of cyclic vomiting syndrome is 2.5 to 5.5 years. Some children, however, continue to have episodes of the disorder into adulthood. About 60 percent of children diagnosed with CVS eventually develop migraine headaches in adolescence or early adulthood. If the more severe complications of prolonged vomiting can be successfully prevented or managed, however, most patients can lead normal lives between acute attacks.
Prevention
Some episodes of vomiting may be prevented by avoiding specific triggers or by taking prophylactic medications. As the cause of the disorder is as of 2004 not yet fully understood, however, there is no way to prevent CVS as a whole.
Parental concerns
Cyclic vomiting syndrome can be a heavy emotional and financial burden on the families of affected children. Episodes of CVS are often upsetting or downright frightening to other family members, in addition to the fact that they often spoil family outings or vacations when they are triggered by excitement or motion sickness. Moreover, CVS can interfere with a child's schooling; most children diagnosed with the disorder miss an average of 20 school days per year and may require tutoring or home schooling.
Boles, R. G., et al. "Maternal Inheritance in Cyclic Vomiting Syndrome with Neuromuscular Disease." American Journal of Medical Genetics 120A (August 1, 2003): 474–82.
Cupini, L. M., et al. "Cyclic Vomiting Syndrome, Migraine, and Epilepsy: A Common Underlying Disorder?" Headache 43 (April 2003): 106–07.
Khasawinah, T. A., et al. "Preliminary Experience with Dexmedetomidine in the Treatment of Cyclic Vomiting Syndrome." American Journal of Therapeutics 10 (July–August 2003): 303–07.
Li, B. U., and L. Misiewicz. "Cyclic Vomiting Syndrome: A Brain-Gut Disorder." Gastroenterology Clinics of North America 32 (September 2003): 997–1019.
Salpietro, C. D., et al. "A Mitochondrial DNA Mutation (A3243G mtDNA) in a Family with Cyclic Vomiting." European Journal of Pediatrics 162 (October 2003): 727–28.
ORGANIZATIONS
Cyclic Vomiting Syndrome Association in the United States and Canada (CVSA—USA/Canada). 3585 Cedar Hill Road, NW, Canal Winchester, OH 43110. Web site: <www.cvsaonline.org>.
National Organization for Rare Disorders Inc. (NORD). 55 Kenosia Avenue, PO Box 1968, Danbury, CT 06813. Web site: <www.rarediseases.org>.
Sundaram, Shikha, and B. UK Li. "Cyclic Vomiting Syndrome." eMedicine, August 10, 2002. Available online at <www.emedicine.com/ped/topic2910.htm> (accessed November 16, 2004).
J. Ricker Polsdorfer, MD
KEY TERMS
Abdominal migraine—Another term that is sometimes used for cyclic vomiting syndrome (CVS).
Idiopathic—Refers to a disease or condition of unknown origin.
Mitochondria—Spherical or rod-shaped structures of the cell. Mitochondria contain genetic material (DNA and RNA) and are responsible for converting food to energy.
Prodrome—Early symptoms that warn of the beginning of disease. For example, the herpes prodrome consists of pain, burning, tingling, or itching at a site before blisters are visible while the migraine prodrome consists of visual disturbances.
Prophylactic—Preventing the spread or occurrence of disease or infection.
