Cyclic Vomiting Syndrome (CVS) Symptoms and Causes

Medically Reviewed on 9/29/2021

Cyclic vomiting syndrome (CVS) definition and facts

Nausea and Vomiting in Children
Nausea can quickly lead to vomiting in some cases.
  • Cyclic vomiting syndrome is a disorder that causes recurrent episodes of nausea, vomiting, and tiredness (lethargy) most often in children but may occur in all age groups.
  • Cyclic vomiting syndrome is generally considered to be a variant of migraines by medical researchers.
  • Research also explored the brain-gut connection as a theory as one cause of the syndrome. However, good evidence for this theory is not supported currently.
  • Symptoms and signs of cyclic vomiting syndrome are repeated attacks of intense nausea, vomiting, and lethargy that last anywhere from an hour to 10 days. Other symptoms and signs may include:
  • The most common causes and triggers of the syndrome are emotional excitement and infections. Other triggers can include:
  • Cyclic vomiting syndrome has four phases: symptom-free, prodrome, vomiting, and recovery.
  • The disease is diagnosed by the patient's history and symptoms; there is no definitive test for cyclic vomiting syndrome.
  • Treatment is done by the patient learning to avoid the causes or triggers of the disorder. During the prodrome, vomiting, and recovery phases, medications are often used to treat the symptoms (for example, antinausea medications, NSAIDs, anti-migraine medications, fluid replenishment, and others).
  • Complications may include pain, reflux, fainting, depression, panic disorder, irritable bowel syndrome, and injury to the esophagus.
  • "Cyclic vomiting syndrome plus" is considered a diagnosis when patients also exhibit symptoms of developmental delay or intellectual disability, muscle weakness (myopathy), and/or seizures.
  • The disorder has a wide range of reported prevalence, about four to 2,000 per 100,000 children, but seems to occur less frequently in adults although the data is not clear.
  • Medical researchers suggest several factors that may contribute to the disorder: brain function disorder, hormonal abnormalities, GI problems, migraine-like conditions, and changes in mitochondrial DNA.
  • Some people may inherit the changes in mitochondrial DNA that may cause or contribute to the development of the disorder.

What is cyclic vomiting syndrome (CVS)?

Cyclic vomiting syndrome is a disorder that causes recurrent episodes of nausea, vomiting, and tiredness (lethargy) that are also termed as “paroxysmal and stereotypic”. This condition is diagnosed most often in young children, but it can affect people of any age. It was first described by Samuel Gee in 1882; the etiology and pathophysiology is unknown but researchers suggest genetic component may play a significant role in this syndrome. CVS is characterized by episodes of rapid vomiting followed with periods of completely normal health - clinicians suggest this off and on again stereotypic vomiting pattern that usually consists of four phases is the diagnostic feature of the syndrome.

4 Phases of cyclic vomiting syndrome

Cyclic vomiting syndrome has four phases:

  1. Symptom-free interval phase: This phase is the period between episodes when no symptoms are present.
  2. Prodromal phase: This phase signals that an episode of nausea and vomiting is about to begin. Often marked by nausea -- with or without abdominal pain -- this phase can last from just a few minutes to several hours. Sometimes, taking medicine early in this phase can stop an episode in progress. Sometimes there is no warning. A person may simply wake up in the morning and begin vomiting.
  3. Vomiting phase: This phase consists of nausea and vomiting; an inability to eat, drink, or take medicines without vomiting; paleness; drowsiness; and exhaustion.
  4. Recovery phase: This phase begins when the nausea and vomiting stop. Healthy color, appetite, and energy return.

Causes of Vomiting

There are numerous causes of nausea and vomiting. These symptoms may be due to the following:

  • Acute gastritis (direct irritation of the stomach lining)
  • Central causes in which signals from the brain cause nausea and vomiting
  • Other illnesses not due to stomach problems
  • Medications and medical treatments
  • Mechanical obstruction of the bowel

Cyclic vomiting syndrome symptoms and signs

Cyclic vomiting syndrome is characterized by attacks of intense nausea, vomiting, and lethargy that last anywhere from an hour to 10 days. A person may vomit several times per hour, potentially leading to a dangerous loss of fluids (dehydration). Additional symptoms can include unusually pale skin (pallor or paleness), abdominal pain, diarrhea, headache, and an increased sensitivity to light (photophobia) or to sound (phonophobia). In most affected people, the signs and symptoms of each attack are quite similar. Consequently, the person with cyclic vomiting syndrome may have one or more of these symptoms and signs:

Cyclic vomiting syndrome attacks can be debilitating, making it difficult for an affected person to go to work or school. Unfortunately, these symptoms and signs listed above can occur with many other diseases; the alternating pattern of symptoms and periods of remission is the major sign of cyclic vomiting syndrome. In addition, most individuals with cyclic vomiting syndrome exhibit the same pattern of symptoms during each cycle of severe nausea and vomiting.

Causes, triggers, and risk factors

Episodes of nausea and vomiting can be caused and triggered by several different factors.

  • The most common causes of cyclic vomiting syndrome are infections (chronic sinusitis, tooth decay, for example) and emotional excitement (panic attacks, anxiety, holidays, parties) with positive situations outnumbering negative.
  • Other triggers can include periods without eating (fasting), temperature extremes of hot or cold, lack of sleep, overexertion, allergies, ingesting certain foods (chocolate, cheese, monosodium glutamate), overeating, alcohol consumption, and menstruation.

Migraine headache: Researchers have suggested migraine-related mechanisms may be involved. For example, patients with CVS have a family prevalence of migraine headaches and many patients with CVS that eventually resolved developed migraine headaches in adulthood.

Mitochondrial DNA (mDNA) also may play a role. Researchers have demonstrated that 86% of children with CVS and neuromuscular disease had mothers with a history of migraine. In children with CVS, mDNA showed high frequency of polymorphic changes in mDNA termed16519T and 3010A.

Sympathetic nerve hyper-responsiveness and autonomic dysfunctions: Patients with CVS appear to have sympathetic nerve hyper-responsiveness and autonomic dysfunction. Symptoms include flushing, paleness to the skin, fever, lethargy, increased saliva production, and diarrhea are at higher risk for developing CVS.

Stress response: Psychological, physical, and infectious episodes are known triggers of this syndrome.

Chronic recreational marijuana use: Chronic marijuana use has been associated with CVS episodes and may be linked to nausea/vomiting through the endocannabinoid system, which is thought to play a role in nausea, vomiting, and stress control. Some researchers suggest that males younger than 19 years of age with CVS-like symptoms should always be asked about marijuana use.

The brain-gut connection or theory has been mentioned as a cause of CVS, especially in the early literature. Although the theory has some support (for example, stress and/or migraines triggers vomiting) other factors (physiological or genetic) may equally trigger the disease. Some others suggest the gut bacteria may trigger CVS if bacterial overgrowth of the normal bacterial flora in the gut occurs but good evidence for this theory is lacking.

Consequently, it is not clear which factors comprise the highest risk factors for CVS. However, most researchers consider the problem to either be caused by, or to have increased risk for CVS when several factors converge (genetic, autonomic, environmental and/or nerve/brain functions) thus resulting in multifactorial causes and risk factors for it. Currently, most researchers conclude the cause(s) are unknown.


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Who gets cyclic vomiting syndrome?

The exact prevalence of cyclic vomiting syndrome is unknown; estimates range from 3.15 to 2,000 per 100,000 children. The condition is diagnosed less commonly in adults, although recent studies suggest that the condition could be as common in adults as in children.

Is it genetic (inherited)?

In most cases of cyclic vomiting syndrome, affected people have no known history of the disorder in their family, but many CVS-affected individuals have a family history of related conditions, such as migraines, in their mothers and other maternal relatives. This family history suggests an inheritance pattern known as maternal inheritance or mitochondrial inheritance, which applies to genes contained in mitochondrial DNA. Disorders with mitochondrial inheritance can appear in every generation of a family and can affect both males and females. However, because mitochondria can be passed from one generation to the next only through egg cells (not through sperm cells), only females pass mitochondrial conditions to their children. In addition, most researchers suggest that CVS development may require other factors to help trigger genetic component.

Which specialties of doctors or other health care professionals treat the condition?

In addition to the patient's primary-care physician or pediatrician, gastroenterologists (doctors who specialize in disorders of the digestive system) are usually consulted. In addition, critical-care specialists (adult or pediatric) may need to be consulted if complications develop.

How do I know if I have CVS (diagnosis)?

Cyclic vomiting syndrome is hard to diagnose because no tests -- such as a blood test or X-ray -- can establish a diagnosis of cyclic vomiting syndrome. A doctor must look at symptoms and medical history to rule out other common diseases or disorders that can cause nausea and vomiting. Making a diagnosis takes time because the doctor also needs to identify a pattern or cycle to the vomiting. For example, the patient who has had at least five separate episodes of vomiting or at least three separate episodes over six months for children or one year for adults, that have had attacks similar to previous episodes (for example, they started the same time of day, last same time span and have the same intensity), makes the diagnosis of CVS more likely.

However, it is not unusual to have laboratory tests such as CT, ultrasound or MRI of the abdomen, magnetic resonance enterography, endoscopy, upper GI series of X-rays, gastrointestinal motility tests, food allergy tests, and others performed to help the physician be sure that diseases with similar symptoms are not causing the problems.

Is there a diet or natrual treatments for this syndrome?

Although home remedies have not been well studied, anecdotal reports suggest at least three remedies may help some patients. They are biofeedback to reduce stress, L-carnitine that helps turn fat into energy, and coenzyme Q10, a substance that aids mitochondrial dysfunction.

Reports of diets that help reduce the frequency of reoccurrence of CVS attacks include gluten-free diets, a Paleo diet (diet based on foods eaten by early humans such as fish, meat, vegetables, and fruit without dairy or green products), and GAPS diet (complicated diet plan designed for individuals with gastrointestinal immune problems). Parents and individuals should check with their physician before utilizing any of these home remedies or diets to avoid any potential side effects or deterioration in the child's or adult's condition.

How is cyclic vomiting syndrome treated?

Treatment varies, but people with cyclic vomiting syndrome generally improve after learning to control their symptoms. People with cyclic vomiting syndrome are advised to get plenty of rest and sleep and to take medications that prevent a vomiting episode, stop one in progress, speed up recovery, or relieve associated symptoms.

Treatment of vomiting phase: Once a vomiting episode begins, treatment usually requires the person 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 nausea continues.

Treatment during the prodromal phase: Sometimes, during the prodromal phase, it is possible to stop an episode from happening. People with nausea or abdominal pain before an episode can ask their doctor about taking ondansetron (Zofran) or lorazepam (Ativan) for nausea or ibuprofen (Advil, Motrin) for pain. Other medications that may be helpful are famotidine (Pepcid, Zantac 360) or omeprazole (Prilosec), which help calm the stomach by lowering the amount of acid it makes.

Treatment during recovery phase: During this phase, it's very important to drink water and replace lost electrolytes. Electrolytes are salts the body needs to function and stay healthy. Symptoms during the recovery phase can vary. Some people find their appetite returns to normal immediately, while others need to begin by drinking clear liquids and then move slowly to solid food.

Frequent and long-lasting episode treatment: People whose episodes are frequent and long-lasting may be treated during symptom-free intervals in an effort to prevent or ease future episodes. Medications that help people with migraine headaches, such as propranolol (Inderal), cyproheptadine (Periactin), and amitriptyline (Elavil), are sometimes used during this phase, but they do not work for everyone. Taking the medicine daily for one to two months may be necessary before one can tell if it helps.

Symptom-free phase: The symptom-free interval phase is a good time to eliminate anything known to trigger an episode. For example, if episodes are brought on by stress or excitement, a symptom-free interval phase is the time to find ways to reduce stress and stay calm. Behavioral therapy may help reduce attacks by reducing stress and anxiety.

Sinus and allergy cause: If sinus problems or allergies cause episodes, those conditions should be treated early to reduce the chance of a CVS attack.

Migraine treatment: During an episode, anti-migraine drugs such as sumatriptan (Imitrex) may be prescribed to stop symptoms of migraine headache. The safety and efficacy of these medications have not been established in children under 18 years of age.

What are the complications if the condition isn't treated?

If the condition is not treated, attacks typically occur four to 12 times per year. Between episodes, vomiting is absent, and nausea is either absent or much reduced. Many affected people experience other symptoms during and between episodes, including pain, digestive disorders such as gastroesophageal reflux (GERD) and irritable bowel syndrome (IBS), and fainting spells (syncope). In addition, complications of CVS can also include dehydration, electrolyte abnormalities, damage to the esophagus, and tooth decay due to the acid in vomit. People with cyclic vomiting syndrome are also more likely than people without the disorder to experience depression, anxiety, and panic disorder. It is unclear how these health conditions are related to nausea and vomiting.


Bowel regularity means a bowel movement every day. See Answer

What is the relationship between cyclic vomiting syndrome and migraines?

Cyclic vomiting syndrome is generally considered to be a variant of migraines, which are severe headaches often associated with pain, nausea, vomiting, and extreme sensitivity to light and sound. Many people with cyclic vomiting syndrome have a family history of migraines, and attacks of nausea and vomiting may be replaced by migraine headaches as an affected person gets older.

What other problems accompany this condition, and what is the prognosis?

Most people with cyclic vomiting syndrome have normal intelligence, although some affected people have experienced developmental delay or intellectual disability, muscle weakness (myopathy), and/or seizures. People with these additional features are said to have cyclic vomiting syndrome plus.

The prognosis for CVS varies. Patients with complications and weak responses to treatment have a fair prognosis while others may respond well and have a good prognosis. In general, CVS lasts about two and a half to five and a half years, resolving late childhood or early adolescence. Some patients go on to develop migraine headaches, and a few patients have CVS extend into adulthood. Patients with a diagnosis of cyclic vomiting syndrome plus have a prognosis usually ranging from fair to poor.

Is it possible to prevent this syndrome?

Most investigators who study CVS suggest there are ways to prevent or reduce the number of CVS attacks. Ways to prevent and/or reduce attacks include the following:

  • Get adequate sleep.
  • Seek help to prevent stress and anxiety.
  • Treat infections and/or allergies early.
  • Avoid any triggers of CVS, especially related to foods.
  • During the well phase, eat a balanced diet with regular meals.
  • Utilize appropriate medications prescribed by a physician to reduce CVS symptoms.

What are the genetic changes related to this syndrome?

Although the exact causes of cyclic vomiting syndrome have yet to be determined, researchers have proposed several factors that may contribute to the disorder. These factors include changes in brain function, hormonal abnormalities, and gastrointestinal problems. Many researchers believe that cyclic vomiting syndrome is a migraine-like condition, which suggests that it is related to changes in signaling between nerve cells (neurons) in certain areas of the brain.

Some cases of cyclic vomiting syndrome may be related to genetic changes in mitochondrial DNA. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA (known as mitochondrial DNA, mDNA, or mtDNA).

Several changes in mitochondrial DNA have been associated with cyclic vomiting syndrome. Some of these changes alter single DNA building blocks (nucleotides), whereas others rearrange larger segments of mitochondrial DNA. These changes likely impair the ability of mitochondria to produce energy. Defects in energy production may lead to symptoms during periods when the body requires more energy, such as when the immune system is fighting an infection. It remains unclear how changes in mitochondrial function are related to recurrent episodes of nausea and vomiting.

What other names do people use for cyclic vomiting syndrome?

  • CVS
  • Cyclical vomiting
  • Cyclical vomiting syndrome
  • Periodic vomiting

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Medically Reviewed on 9/29/2021

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