Cyclic vomiting syndrome (NORD)

Cyclic vomiting syndrome, or CVS for short, is a disorder characterized by recurrent or cyclic episodes of severe nausea and vomiting. CVS can occur at any age, but is typically more common and severe in children.

Episodes of nausea and vomiting may last for a few hours to several days. They generally have sudden onset, resolve for a period of time, and are similar each time.

In some people, especially adults, nausea and vomiting may continue between episodes,but the intensity is far less severe than during episodes.

Episodes may occur a few times a year or as frequently as several times a month. Episodes may return like clockwork, and monthly episodes are common. They can occur at times of stress, or be apparently random.

During an episode, vomit can be bilious, appearing green or yellow. Children may experience bouts of projectile vomiting as frequently as four or more times per hour, which can potentially lead to dehydration and electrolyte imbalances, involving sodium and potassium.

Episodes can also be associated with severe abdominal pain, retching, and diarrhea, as well as decreased appetite and weight loss.

Some individuals may also experience migraine-like symptoms, like headaches and sensitivity to light and sound, as well as fever, dizziness, a lack of energy, and pallor.

In severe cases, an individual can become incapacitated and unable to walk or talk until the episode resolves. The exact cause of CVS is still unknown, but it seems to have many contributing factors.

The nervous system is thought to play a role. Nerves deliver messages throughout the body, including between the brain and gut, to coordinate functions.

Most individuals with CVS have migraines or a family history of migraines. In fact, CVS is sometimes called “abdominal migraine”.

Gastrointestinal motility may also have a role. The gastrointestinal tract has a layer of smooth muscles, which normally help push food, liquid, and gas from the esophagus down to the rectum.

In some individuals with CVS, gastrointestinal motility doesn’t function properly, which is known as dysmotility.

Dysmotility may also occur between vomiting episodes, resulting in conditions like gastroesophageal reflux, gastroparesis, and irritable bowel.

Other factors contributing to CVS may include changes or mutations in mitochondrial genes, as well as abnormal function of the autonomic nervous system called dysautonomia, and an overactive response to stress.