Characterized by severe episodes of recurrent vomiting attacks and nausea, cyclic vomiting syndrome (CVS) is a rare disorder with no apparent cause. There are several synonyms that are used to typify the condition.
Abdominal migraine, periodic syndrome, childhood cyclic vomiting, and cyclical vomiting are some of the terminologies that are used to describe CVS, which was first documented in 1882 by Samuel Gee.
Nausea and vomiting may be accompanied by symptoms such as abdominal pain and headaches. A CVS episode may have a duration short in range that lasts a few hours or a long duration that may last up to several days. Each episode is followed by a period of relief from nausea and / or vomiting before the next occurs.
The cyclic pattern of sickness followed by relief that is observed with CVS helps to clearly distinguish it from other pathologies of similar nature.
Clinical Presentation and Diagnosis
The typical patient is around the age of 5 years at the onset of CVS. However, the disorder is known to also occur in infants during the neonatal period and in adults after the seventh decade of life. All races are affected by the condition, but there is a disproportionate distribution to whites and a slight predilection for females.
Moreover, many patients are not diagnosed until well into the second year after the onset of symptoms.
The vomiting associated with CVS is a lot more severe than that of other conditions such as gastroesophageal reflux and children tend to have a higher rate of vomiting per hour in comparison to adult patients.
Up to a third of patients with CVS may experience diarrhea and/ or fever, pallor, and lethargy. Reported associated symptoms include phonophobia (extreme sensitivity to sound), photophobia (extreme sensitivity to light), and vertigo (dizziness).
The diagnostic criteria that must be met in children with CVS are:
- A minimum of 5 episodes of intense and relentless vomiting accompanied by nausea that lasts hours to days or a minimum of 3 episodes over a period of 6 months
- Attacks that last from 1 hour to 10 days and are at minimum a week apart
- The patient must have symptoms and patterns that are stereotypical for CVS
- A return to normal health during/ after episodes
- Other disorders that can cause similar symptoms must be ruled out
The diagnostic criteria that must be met for adults are:
- A minimum of 3 episodes in a year
- Stereotypical CVS vomiting that lasts less than a week
- Disease-free periods
- All other disorders must be excluded as potential causes of the symptoms
While the etiology of CVS remains unknown, there are several theories that have been postulated. Several studies have suggested that CVS is mediated by mechanisms involving a connecting pathway between the gut and central nervous system.
Some studies indicate a potential link between familial migraine headaches, while others claim that mutations in mitochondrial DNA may be implicated in the pathogenesis of the disorder.
Other factors with potential pathogenic roles include autonomic dysfunction and sympathetic hyper-responsiveness as well as long-term marijuana usage and even compulsive use of hot water while bathing.
Treatment and Prognosis
As one would expect, there is no cure for CVS due to the limited understanding with regards to its pathogenesis. Therefore, all available therapies that are used today are empirical. The primary aim of these therapies is to prevent, intervene, and treat the CVS-related symptoms.
These therapies use strategies such as ensuring means to avoid triggering events, prophylactic agents, and supportive treatment during attacks.
Triggers of CVS may arise from dietary intake as well as psychological stress, sleep deprivation, and medications. The pharmacotherapy used to treat CVS ranges from anti-emetics to anti-migraine and pain-killing agents. Additional supportive therapy during attacks include intravenous fluid administration and sedatives.
Family members of those affected are encouraged to receive and utilize resources such as support groups and conferences in order to be better equipped to assist their loved ones. CVS, according to several studies, lasts on average up to 6 years and resolves by late childhood or even early adolescence with very few patients being affected into their adulthood.