Cyclic Vomiting Syndrome

Cyclical vomiting syndrome, CVS


Cyclic vomiting syndrome (US English) or cyclical vomiting syndrome (UK English) (CVS) is a chronic functional condition of unknown etiology characterised by recurring attacks of intense nausea, vomiting, and sometimes abdominal pain, headaches, or migraines. CVS typically develops during childhood, usually between ages 3 and 7; although it often remits during adolescence, it can persist into adult life.

Symptoms - Cyclic Vomiting Syndrome

Sufferers may vomit or retch six to twelve times an hour, and an episode may last from a few hours to well over three weeks, and in some cases months, with a median episode duration of 41 hours. Acid, bile and (if the vomiting is severe) blood may be vomited. Some sufferers will ingest water to reduce the irritation of bile and acid on the esophagus during emesis. Between episodes the sufferer is usually normal and healthy otherwise but can be in a weak state of fatigue or suffer from muscle pain. In approximately half of cases the attacks, or episodes, occur in a time-related manner. Each attack is stereotypical: that is, in any given individual, the timing, frequency and severity of attacks is similar.

Episodes may happen every few days, every few weeks 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, heightened sensitivity, especially to light, though sensitivity to smell, sound, pressure, and temperature, as well as oncoming muscle pain and fatigue, are also reported by some patients. The majority of sufferers can identify triggers that may precipitate an attack. The most common are various foods, infections (such as colds), menstruation, extreme physical exertion, lack of sleep, and psychological stresses both positive and negative.

A sufferer may also be light-sensitive (photophobic) during an attack, as well as sound-sensitive (phonophobic) and, less frequently, temperature- or pressure-sensitive. Some sufferers also have a strong urge to bathe in warm or cold water. Some sufferers report that they experience a restless sensation or stinging pain along the spine, hands, and feet followed by weakness in both legs. Some of these symptoms may be due to dehydration rather than the underlying cause of CVS.

Causes - Cyclic Vomiting Syndrome

The cause of cyclic vomiting syndrome is unknown. But the bouts of vomiting that characterize the syndrome can be triggered by:

  • Colds, allergies or sinus problems
  • Emotional stress or excitement, especially in children
  • Anxiety or panic attacks, especially in adults
  • Foods, such as chocolate or cheese
  • Overeating or eating right before going to bed
  • Hot weather
  • Physical exhaustion
  • Menstruation
  • Motion sickness

Prevention - Cyclic Vomiting Syndrome

Many people know what triggers their cyclic vomiting episodes. Avoiding those triggers can reduce the frequency of episodes.

If episodes occur more than once a month or require hospitalization, your doctor may recommend preventive medicine. Lifestyle changes also may help, including:

  • Getting adequate sleep
  • Downplaying the importance of upcoming events because excitement can be a trigger
  • Avoiding trigger foods, such as cheese and chocolate
  • Eating three small meals and three snacks daily at regular times

Diagnosis - Cyclic Vomiting Syndrome

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.

Diagnostic criteria

There are established criteria to aid in diagnosis of CVS; essential criteria are:

  1. A history of three or more periods of intense, acute nausea and unremitting vomiting, as well as pain in some cases, lasting hours to days and even weeks or months
  2. Intervening symptom-free or reduced-symptom intervals, lasting weeks to months
  3. There are repeated cycles of periods (of varying duration) with intense/acute nausea, with or without vomiting, with or without severe pain, followed by periods of reduced symptoms, followed by gradual increase in CVS symptoms until it peaks (peak intensity is generally relative to cycle intensity).
  4. There are differences between early-onset CVS (babies & children) and late onset CVS (adult)
  5. Exclusion of metabolic, gastrointestinal, or central nervous system structural or biochemical disease, e.g., individuals with specific physical causes (such as intestinal malrotation)
Once formal investigations to rule out gastrointestinal or other etiologies have been conducted, these tests do not need to be repeated in the event of future episodes.

Prognosis - Cyclic Vomiting Syndrome

Fitzpatrick et al. (2007) identified 41 children with CVS. The mean age of the sample was 6 years at the onset of the syndrome, 8 years at first diagnosis, and 13 years at follow-up. As many as 39% of the children had resolution of symptoms immediately or within weeks of the diagnosis. Vomiting had resolved at the time of follow-up in 61% of the sample. Many children, including those in the remitted group, continued to have somatic symptoms such as headaches (in 42%) and abdominal pain (in 37%).

Most children who have this disorder miss on average 24 school days a year. The frequency of episodes is higher for some people during times of excitement. Charitable organizations to support sufferers and their families and to promote knowledge of CVS exist in several countries.


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 electrolyte imbalances. The patient can also become malnourished if the attacks last too long without adequate replenishment of nutrients. With adequate medical interventions, most patients can be properly supported during an episode.

Treatment - Cyclic Vomiting Syndrome

There is no known cure for CVS, but there are medications that can be used for treatment, intervention, and prevention. There is a growing body of publications on both individual cases and the experiences of the CVS cohort. 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. For a number of patients, potent anti-emetic drugs such as ondansetron (Zofran) or granisetron (Kytril), and dronabinol (Marinol) may be helpful in either preventing an attack, aborting an attack, or reducing the severity of an attack. Lifestyle changes may be recommended, such as extended rest and reduction of stress. Because the symptoms of CVS are similar (or perhaps identical) to those of the disease well-identified as "abdominal migraine," treatment of CVS with a regimen of anti-migraine drugs, such as topiramate and amitriptyline, is showing promise in preventing recurrent attacks.

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