What is cyclic vomiting syndrome?

Cyclic vomiting syndrome (CVS) is a condition that involves recurrent episodes of vomiting with three main features: sudden onset, stereotypical (similar episodes), and periods of wellness between episodes. There is not a single test to diagnose cyclic vomiting syndrome; diagnosis is often made by history, physical exam and tests to exclude other diseases. CVS occurs in about 1 in 33,000 children and can often be so severe it keeps the affected person from participating in daily activities.

What causes cyclic vomiting syndrome?

There is no known cause for the recurrent symptoms and episodes of cyclic vomiting that can last from several hours to a few days. Studies have indicated that cyclic vomiting syndrome is strongly linked to migraines. Theoretical causes include dysautonomia, specific mitochondrial DNA mutations, and heightened stress response that activates the vomiting response system.

Signs and symptoms of cyclic vomiting

CVS symptoms include vomiting episodes that recur in a cyclical pattern (for example every two weeks or once a month). The vomiting episodes start suddenly, typically beginning with nausea, and progress to vomiting later. The episodes can sometimes wake the affected person from sleep.

The episodes are “stereotypical” which means that each new episode resembles previous episodes. Other symptoms can include stomach pain, diarrhea and headache. The vomiting “attacks” can become so severe that patients become dehydrated and require medical attention.

In between episodes, patients generally feel completely well. Once an episode resolves, affected children often feel normal within hours.

Overlap diagnoses

Many children with CVS also have a diagnosis of migraines or a family history of migraines.

Other causes of recurrent vomiting include:

• Gastroesophageal reflux disease
• Stomach inflammation (gastritis)
• Pancreas inflammation (pancreatitis)
• Food allergies
• Kidney/urologic abnormalities (ureteropelvic junction obstruction)
• Stomach infections
• Cannabis abuse
• Brain tumors or other lesions in the head
• Metabolic disease

Testing and diagnosis of cyclic vomiting syndrome

The diagnosis of cyclic vomiting syndrome is based mostly on the history and symptoms presented. Physicians may often perform tests to exclude other conditions. These may include:

• Upper gastrointestinal tract radiography, commonly called an upper GI. A patient swallows a contrast agent and a series of X-rays are performed to evaluate the esophagus, stomach, and a portion of the small intestine. This test is used to evaluate for malrotation, an abnormal twisting of the intestine.
• Abdominal ultrasound. A diagnostic imaging technique which creates images from the rebound of high-frequency sound waves in the internal organs. It is used to evaluate for potential diseases in the kidneys or gallbladder.
• MRI of the brain. Magnetic resonance imaging (MRI) is an imaging procedure that uses a powerful magnet, radiofrequencies and a computer to produce detailed images of the brain. This test is used to exclude possible neurologic causes of vomiting.
• Blood tests. These tests may be done during a cyclic vomiting episode to evaluate for infection, inflammation of the pancreas or metabolic enzyme problems.
• Endoscopy. A test that uses a small, flexible tube with a light and a camera lens at the end (endoscope) to examine the inside of the digestive tract. Tissue samples may also be taken from inside the GI tract for further examination and testing.