Cyclic vomiting syndrome (CVS) is a chronic functional condition of unknown pathogenesis. CVS is characterized as recurring episodes lasting a single day to multiple weeks. Each episode is divided into four phases: inter-episodic, prodrome, vomiting, and recovery. Inter-episodic phase (symptom free phase), is characterized as no discernible symptoms, normal everyday activities can occur, and this phase typically lasts one week to one month. The prodrome phase is known as the pre-emetic phase, characterized by the initial feeling of an approaching episode, still able to keep down oral medication. Emetic or vomiting phase is characterized as intense persistent nausea, and repeated vomiting typically lasting hours to days. Recovery phase is typically the phase where vomiting ceases, nausea diminishes or is absent, and appetite returns. This syndrome is most commonly seen in children usually between ages 3 and 7, however adult diagnosis is quite common. This disorder is thought to be closely related to migraines and family history of migraines. Signs and symptoms
Affected individuals may vomit or retch 6–12 times in an hour and an episode may last from a few hours to over three weeks and in some cases months, with a median episode duration of 41 hours. Stomach acid, bile and, if the vomiting is severe, blood may be vomited. Some with the condition will ingest water to reduce the irritation of bile and acid on the esophagus during emesis. Between episodes, the affected individual is usually normal and healthy otherwise but can be in a weak state of fatigue or experience muscle pain.
Treatment
Treatment for cyclic vomiting syndrome depends on the evident phase of the disorder.Because the symptoms of CVS are similar (or perhaps identical) to those of the disease well-identified as "abdominal migraine,"  prophylactic migraine medications, such as topiramate and amitriptyline, have seen recent success in treatment for the prodrome and vomiting phases, reducing the duration, severity, and frequency of episodes.Therapeutic treatment for the prodromal phase, characterized by the anticipation of an episode, consists of sumatriptan (nasal or oral) an anti-migraine medication, anti-inflammatory drugs to reduce abdominal pain, and possible anti-emetic drugs. These options may be helpful in preventing an episode or reducing the severity of an attack.The most common therapeutic strategies for those already in the vomiting phase 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. Many patients seek comfort during episodes by taking prolonged showers and baths typically quite hot. The use of a heating pad may also help reduce abdominal pain.Lifestyle changes may be recommended, such as extended rest, reduction of stress, frequent small meals, and to abstain from fasting.