Cyclic Vomiting Syndrome

Etiology

The exact cause of CVS is unknown. In the pediatric patient, CVS is considered by many to be a precursor to migraines later in life. The relationship between the two has been well studied, but no exact cause has been identified. Other studies have made associations with autonomic disturbances or mitochondrial dysfunction. Allergies to foods, stressful triggers, and lack of sleep are also associated with CVS. There is an increased frequency during patient menstrual cycles, suggesting a possible hormonal trigger for CVS. Longterm cannabis use has been associated with CVS as well.

Epidemiology

It is hard to determine true incidence and prevalence because many patients are misdiagnosed, but the estimated prevalence is 1.9% to 2.3% with an incidence of 3.2/100,000. CVS is more common in whites and slightly more common in females. Children often develop the condition by age 3 to 7, but CVS has been reported in infants as well as elderly patients. Adults who have CVS may develop the disease without any childhood episodes.

Pathophysiology

The pathophysiologic process of CVS is unclear. Nausea and vomiting are hallmarks of this disease but are very nonspecific. Multiple illnesses and conditions cause nausea and vomiting. Relationships between migraines, menstrual cycle, autonomic dysfunction, and mitochondrial disease are known but not fully understood.

Toxicokinetics

There is a relationship between repeated cannabis use and CVS. The science behind this is unclear but the cessation of cannabis for several weeks improves symptoms. 

History and Physical

The patient will often describe a sudden onset of vomiting. Abdominal pain is a common complaint as well. Many describe nausea, anorexia, and fatigue prior to the onset of vomiting. These episodes may last hours to days. In between episodes, patients describe pain-free and symptom-free intervals that last weeks to months. The hallmark of this disease is the recurrence of vomiting cycles, so patients will often report multiple visits to multiple providers in search of a diagnosis and symptom relief. Patients may report previous surgeries such as cholecystectomy without improvement of symptoms. Exam findings are nonspecific but often reflect dehydration. Findings such as dry mucous membranes, tachycardia, and possible abdominal tenderness may be present but are nondiagnostic for CVS.

Evaluation

Many patients undergo extensive testing that includes complete blood count, comprehensive metabolic profile, lipase, urinalysis, gallbladder ultrasound, and possible CT scan of abdomen and pelvis. These tests are often repeated with subsequent episodes while trying to determine a cause. Esophagogastroduodenoscopy is often performed as well.

There are several sets of criteria to consider for diagnosis of CVS. 

Rome IV Criteria 

Rome IV criteria include the presence of all of the following:

• Stereotypical episodes of vomiting regarding onset (acute) and duration (less than one week)
• Three or more discrete episodes in the prior year, and two episodes in the past 6 months, occurring at least one week apart
• An absence of vomiting between episodes, but other milder symptoms can be present between cycles

The criteria should be fulfilled for the last 3 months with symptom onset at least 6 months before diagnosis.

Supportive Criteria

• History or family history of migraine headaches

North American Society for Pediatric Gastroenterology Hepatology and Nutrition(NASPGHAN) 

A consensus by the NASPGHAN suggests the following diagnostic criteria(all of which must be met). These recommendations apply to children and adolescents.

• At least five attacks in any interval or a minimum of three attacks during a 6 month period
• Episodic attacks of intense nausea and vomiting lasting 1 hour to 10 days and occurring at least 1 week apart
• Stereotypical pattern and symptoms in the individual patient
• Vomiting during attacks occurs at least four times per hour for at least 1 hour
• Return to baseline health between episodes
• Not attributed to another disorder

Treatment / Management

There is no cure for CVS. Treatment can be divided into three categories: prophylactic, abortive and supportive. Supportive treatment is the mainstay in emergency departments whether or not there has been a diagnosis of CVS. Intravenous fluids and nausea medications such as ondansetron or prochlorperazine are given. Ketorolac is often given for pain. Sometimes sedation with lorazepam or diphenhydramine is effective. Rest and a quiet, dark environment are recommended.[1][2][3](B3)

Because some studies have linked migraines to CVS, sumatriptan has been used as an abortive therapy once the diagnosis has been made. Amitriptyline has been tried in low doses for prophylactic therapy. Other medications that have been studied to prevent CVS are cyproheptadine, propranolol, topiramate, and erythromycin. Multiple studies have evaluated these medications with varying results. There is no clear evidence-based medication to use in every episode.[4][5]

Labs should be ordered to assess hydration status. Other treatments would include correction of dehydration or electrolyte imbalance. 

Many times patients present to the emergency department without a clear diagnosis. A thorough history is important to narrow the differential and treatment plan. Providers should have a high index of suspicion when repeated episodes are reported without any cause found. Previous abdominal surgeries without symptom resolution should cause the clinician to consider CVS. When the diagnosis is suspected, referral to a pediatric or adult gastroenterologist should be made.

Differential Diagnosis

Because many conditions start with nausea and vomiting, the differential is expansive. Gastroenteritis, gallbladder disease, peptic ulcer disease, appendicitis, pancreatitis are routinely in the differential. Considerations include infectious or toxic causes, mechanical obstruction, irritable bowel syndrome, psychiatric causes, neurological causes, metabolic causes, and pregnancy in the female of childbearing age. 

Prognosis

Although there is no cure for CVS, reduction in triggers such as sleep deprivation or stress can decrease episodes. Some children outgrow CVS, but it is difficult to determine which patients will cease from future vomiting cycles. Adolescents and adults should be asked about cannabis usage because cessation can decrease or even end CVS.

Complications

Complications include renal injury due to dehydration or electrolyte abnormality. Mallory Weiss tears and gastritis can be seen after an episode of vomiting. Another type of complication would be unnecessary surgeries or procedures without relief of symptoms or complications from those procedures.