Cyclic Vomiting Syndrome

Cyclic Vomiting Syndrome (CVS) is a disorder in which otherwise normal people experience repetitive episodes of severe nausea and vomiting that last for several hours to several days, interrupted by longer periods with no symptoms. CVS has no known cause. Episodes are similar to one another in terms of the time of onset, the duration, and the severity. Although CVS can begin at any age in children and adults, it usually starts between the ages of 3 and 7, when it is considered a functional gastrointestinal disorder of childhood. In adults, episodes tend to occur less often than they do in children, but they last longer. Furthermore, the events or situations that trigger episodes in adults cannot always be pinpointed as easily as they can in children.

Episodes can be so severe that a person may have to stay in bed for days, unable to go to school or work. No one knows for sure how many people have CVS, but medical researchers believe that more people may have the disorder than is commonly thought (as many as 1 in 50 children in one study). Because other more common diseases and disorders also cause cycles of vomiting, many people with CVS are initially misdiagnosed until the other disorders can be ruled out.

The Four Phases of CVS
CVS has four phases: the prodrome, the episode of nausea and vomiting itself, the recovery phase, and the symptom-free interval.

The prodrome phase signals that an episode of nausea and vomiting is about to begin. This phase, which is often marked by abdominal pain, can last from just a few minutes to several hours. Sometimes the prodromal phase does not proceed to nausea and vomiting; at other times, nausea and vomiting are not foreshadowed by a prodrome. The episode phase consists of nausea and vomiting; inability to eat, drink, or take medicines without vomiting. The recovery phase begins when the nausea and vomiting stop. Healthy color, appetite, and energy return. The symptom-free interval phase is the period between episodes when no symptoms are present.

Triggers
In retrospect, many people with CVS can identify circumstances that triggered an episode. Commonly-reported triggering events include infections, allergies, or sinus problems. Emotional stress or excitement can trigger episodes as well. Other reported triggers include eating certain foods (such as chocolate or cheese), eating too much, or eating just before going to bed. Hot weather, physical exhaustion, menstruation, and motion sickness can also trigger episodes.

Symptoms
The main symptoms of CVS are severe vomiting, nausea, and retching (gagging). Episodes usually begin at night or first thing in the morning and may include vomiting or retching as often as six to 12 times an hour during the worst of the episode. Episodes usually last anywhere from 1 to 5 days, though they can last for up to 10 days.

Other symptoms include pallor, exhaustion, and listlessness. Sometimes the nausea and vomiting are so severe that a person appears to be almost unconscious. Sensitivity to light, headache, fever, dizziness, diarrhea, and abdominal pain may also accompany an episode.

In addition, the vomiting may cause drooling and excessive thirst. Drinking water usually leads to more vomiting, though the water can dilute the acid in the vomit, making the episode a little less painful. Continuous vomiting can lead to dehydration, which means that the body has lost excessive water and salts.

Diagnosis
CVS is hard to diagnose because no clear tests&mdash;such as a blood test or x ray&mdash;exist to identify it. CVS is a diagnosis of exclusion, meaning that other causes of vomiting must be ruled out.

CVS and Migraine
The relationship between migraine and CVS is still unclear, but medical researchers believe that the two are related. First, migraine headaches, which cause severe pain in the head; abdominal migraine, which causes stomach pain; and CVS are all marked by severe symptoms that start quickly and end abruptly, followed by longer periods without pain or other symptoms.

Second, many of the situations that trigger CVS also trigger migraines. Those triggers include stress and excitement.

Third, research has shown that many children with CVS either have a family history of migraine or develop migraines as they grow older.

Because of the similarities between migraine and CVS, doctors treat some people with severe CVS with drugs that are also used for migraine headaches. The drugs are designed to prevent episodes, reduce their frequency, or lessen their severity.

Treatment
CVS cannot be cured. Treatment varies, but people with CVS are generally advised to get plenty of rest; sleep; and take medications that prevent a vomiting episode, stop or alleviate one that has already started, or relieve other symptoms.

Once a vomiting episode begins, treatment is supportive. It helps to stay in bed and sleep in a dark, quiet room. Severe nausea and vomiting may require hospitalization and intravenous fluids to prevent dehydration. Sedatives may help if the nausea continues.

Sometimes, during the prodrome phase, it is possible to stop an episode from happening altogether. For example, people who feel abdominal pain before an episode can ask their doctor about taking ibuprofen to try to stop it. Other medications that may be helpful are ranitidine or omeprazole, which help calm the stomach by lowering the amount of acid it makes.

During the recovery phase, drinking water and replacing lost electrolytes are very important. Electrolytes are salts that the body needs to function well and stay healthy. Symptoms during the recovery phase can vary: Some people find that their appetites return to normal immediately, while others need to begin by drinking clear liquids and then move slowly to solid food.

People whose episodes are frequent and long-lasting may be treated during the symptom-free intervals in an effort to prevent or ease future episodes. Medications that help people with migraine headaches&mdash;propranolol, cyproheptadine, and amitriptyline&mdash;are sometimes used during this phase.

Complications
The severe vomiting that defines CVS is a risk factor for several complications:


 * Dehydration. Vomiting causes the body to lose water quickly.
 * Electrolyte imbalance. Vomiting also causes the body to lose the important salts it needs to keep working properly.
 * Peptic esophagitis. The esophagus (the tube that connects the mouth to the stomach) becomes injured from the stomach acid that comes up with the vomit.
 * Hematemesis. The esophagus becomes irritated and bleeds, so blood mixes with the vomit.
 * Mallory-Weiss tear. The lower end of the esophagus may tear open or the stomach may bruise from vomiting or retching.
 * Tooth decay. The acid in the vomit can hurt the teeth by corroding the tooth enamel.