Cyclic vomiting syndrome

Overview
Cyclic vomiting syndrome (US English) or cyclical vomiting syndrome (UK English) (CVS) is a condition whose symptoms are recurring attacks of  intense nausea, vomiting and sometimes abdominal pain and/or headaches or migraines. CVS can affect both children and adults. It was first described in the 19th century with one of the earliest references being that of Samuel Gee in 1882. Onset of the condition is possible at any age but is seen to occur more often in a young age. Why anyone develops it is not clear since it is of unknown etiology. There is a strong suggestion of maternal inheritance. A background of migraines could also be the cause of Cyclic Vomiting Syndrome.

Background
CVS differs from other forms of vomiting as it is an acute condition. Sufferers may vomit six times an hour and an episode may last from 1 day to over 2 weeks. Some people find it hard to conceive how anyone can vomit after that length of time, as the stomach will have emptied after the first few emeses. Acid, bile and; if the vomiting is severe, blood, may be vomited. Some sufferers will intentionally ingest water to reduce the irritation of bile and acid on the esophagus during emeses. Between episodes the sufferer is usually otherwise normal and healthy. The median duration of an episode is 41 hours (Li & Fleisher 1999). In approximately half of sufferers the attacks, or episodes, occur in a time related manner. Each attack is stereotypical, i.e. in any given individual their timing, frequency and severity of attacks is similar.

Episodes may happen every few days or every few months. For some there is not a pattern in time that can be recognized. Some sufferers have a warning of an attack, they may experience a prodrome, usually intense nausea and pallor. The majority of sufferers, but not all can identify "triggers" that may precipitate an attack.

The most common are various foods, infections (such as colds), extreme physical exertion, lack of sleep, and psychological stresses both positive and negative.

During an attack a sufferer may be light sensitive (photophobic), sound sensitive (phonophobic) and may take on a semi-conscious state.

Diagnostic criteria
The cause of CVS has not been determined, there are no diagnostic tests for CVS. Several other medical conditions can mimic the same symptoms, and it is important to rule these out. If all other possible causes have been excluded a diagnosis of CVS may be appropriate.

There are established criteria to aid diagnosis of CVS, essential criteria are


 * 1) A history of three or more periods of intense, acute nausea, and unremitting vomiting lasting hours to days
 * 2) Intervening symptom-free intervals, lasting weeks to months
 * 3) Exclusion of metabolic, gastrointestinal or central nervous system structural or biochemical disease e.g. individuals with specific physical causes (e.g. intestinal malrotation)

Treatment
There is no set cure for Cyclic Vomiting Syndrome, but there are medications that can be used to treat, intervene in, and prevent attacks. There is a growing body of publications on either individual cases or experiences of cohorts of CVS patients. Treatment is usually on an individual basis, based on trial and error.

The most common therapeutic strategies for those already in an attack are maintenance of salt balance by appropriate intravenous fluids and; in some cases, sedation. Having vomited for a long period prior to attending a hospital, patients are typically severely dehydrated and suffer from massive volume depletion. Abortive therapy has limited success, but for a number of patients potent anti-emetic drugs such as ondansetron (Zofran) or granisetron (Kytril), dronabinol (Marinol), and more recently (and under careful medical supervision) aprepitant (Emend) may be helpful in either preventing an attack, aborting an attack or reducing the severity of an attack.

The prevalence of the condition is not clear. Two published studies on childhood CVS suggest nearly 2% of school age children may have CVS. However, diagnosis is problematic and as knowledge of CVS has increased in recent years more and more cases are emerging. This suggests a tendency for underdiagnosis, and thus the true figure may be higher.

CVS may be related to migraine, CVS sufferers have a much higher number of first degree relatives who have migraine than is the case in the general population. Some CVS sufferers have symptoms similar to abdominal migraine, but in others the relationship is far less strong and they can't relate to migranous symptoms. Some sufferers obtain some relief from anti-migraine treatments, but they are not universally effective.

Charitable organizations to support sufferers and their families and to promote knowledge of CVS exist in several countries.

Mortality
There is little hard evidence of death as a result of the condition. However, in severe cases the fluid loss can lead to potentially life-threatening salt imbalances and extremely high blood pressure often develops during an attack. In underdeveloped countries it remains probable that CVS may contribute to mortality. In the developed world with adequate medical interventions most sufferers can be supported during an attack and will recover from the episode. After the average three year duration of Cyclic Vomiting Syndrome, 20 percent of patients were to seen to have developed migraines. Patients seemed to go through three stages: CVS, abdominal migraines which have similar characteristics as CVS then regular migraines.

On average 50% of patients require IV fluids. Whereas rotavirus gastroenteritis has less than 1% which require IV fluids. On average the cost of treatment, testing, work absences and leave per year can total in US dollars $17,000. Most children who have this disorder miss on average 24 school days a year, and will often need tutoring to catch up on their academic studies. The frequency of episodes is higher, for some people, during times of excitement, which often leads to many family events such as holidays, birthdays and vacations being disrupted. For adult sufferers the challenge of maintaining a career or full time employment is considerable. For all sufferers there are associated quality of life issues for not only the sufferer but also for close family members.

Average Age
The average age at onset is 3-7 years, but CVS has been seen in infants which are as young as 6 days and in adults which are as old as 73 years (Li and Misiewicz, 2003). Typical delay in diagnosis from onset of symptoms is 2.7 - 3 years (Li and Misiewicz, 2003).

Sex/Race
Females show a slight predominance over males; the female-to-male ratio is 57:43 (Li and Kagalwalla, 2002). CVS occurs in all races but seems to disproportionately affect whites.