What is cyclic vomiting syndrome?

Cyclic Vomiting Syndrome (CVS)

Cyclic Vomiting Syndrome (CVS) is a chronic disorder characterized by stereotypical episodes of acute-onset, intense vomiting lasting less than 7 days, with at least 3 discrete episodes per year separated by symptom-free periods, affecting approximately 2% of the US population. 1, 2

Diagnostic Criteria

According to the Rome IV criteria, CVS diagnosis requires:

• Stereotypical episodes of acute-onset vomiting lasting <7 days
• At least 3 discrete episodes in a year, with 2 occurring in the prior 6 months
• Episodes separated by at least 1 week of baseline health
• Absence of vomiting between episodes 2

A personal or family history of migraine headaches is considered a supportive criterion for diagnosis.

Clinical Features and Phases

CVS progresses through four distinct phases:

1. Prodromal Phase (occurs in ~65% of patients):

   • Lasts a median of 1 hour before vomiting onset
   • Symptoms include impending sense of doom, panic, and communication difficulties
   • Critical time for intervention to potentially abort an episode 2

2. Emetic/Vomiting Phase:

   • Characterized by uncontrollable retching and vomiting lasting hours to days
   • Patients may experience:
     • Constitutional symptoms: fatigue, feeling hot/cold
     • Cognitive/affective symptoms: mental fog, anxiety, restlessness
     • Autonomic symptoms: diaphoresis, flushing
     • Motor symptoms: shakiness, tremulousness
     • Abdominal pain
   • Early morning onset is common 1, 2

3. Recovery Phase:

   • Gradual resolution of symptoms

4. Interepisodic/Remission Phase:

   • Symptom-free periods between episodes 2

Classification

CVS can be classified as:

• Mild CVS: <4 episodes/year each lasting <2 days, without ED visits or hospitalizations
• Moderate-Severe CVS: ≥4 episodes/year, each lasting >2 days, requiring ED visits or hospitalizations 2

Common Comorbidities

• Mood disorders (anxiety, depression, panic disorder): 50-60% of patients
• Migraine: 20-30% of patients
• Seizure disorders: approximately 3% of patients
• Autonomic imbalances including postural orthostatic tachycardia syndrome 2

Triggers

Triggers are identified in 70-80% of patients and include:

• Stress
• Sleep deprivation
• Hormonal fluctuations
• Travel and motion sickness
• Physiological stressors
• Prolonged fasting
• Intense exercise 2

Diagnostic Approach

The American Gastroenterological Association recommends:

• Basic laboratory workup
• One-time upper GI evaluation to exclude obstructive lesions 1, 2

Important conditions to rule out:

• Addison's disease
• Hypothyroidism
• Hepatic porphyria
• Neurological conditions
• Cannabinoid hyperemesis syndrome (CHS) 2

Management

Acute Episode Management

1. Early intervention during prodromal phase:

   • Place patient in a dark, quiet room
   • Aggressive IV hydration with dextrose-containing fluids (10% dextrose in normal saline)
     • Initial bolus of 10-20 mL/kg followed by maintenance fluids
   • Electrolyte replacement as needed 2

2. Medications for acute episodes:

   • Antiemetics: ondansetron 8 mg every 6-8 hours
   • Metoclopramide: 10-20 mg every 6 hours
   • Haloperidol: 0.5-2 mg every 4-6 hours (for refractory vomiting)
   • Benzodiazepines (lorazepam): 0.5-2 mg every 4-6 hours (for sedation and anxiety)
   • Sumatriptan: nasal spray or subcutaneous injection (abortive treatment)
   • Aprepitant: 125 mg day 1,80 mg days 2-3 (severe refractory cases)
   • Olanzapine: 5-10 mg PO daily (for breakthrough nausea and vomiting) 2

Prophylactic Management

First-line prophylactic medications:

• Tricyclic antidepressants (amitriptyline) for adults and children ≥5 years
• Cyproheptadine for children <5 years 2

Second-line options:

• Propranolol
• Topiramate
• Aprepitant
• Zonisamide
• Levetiracetam 2

Long-term Management

Essential components include:

• Identifying and avoiding personal triggers
• Maintaining regular sleep patterns
• Avoiding prolonged fasting
• Implementing stress management techniques
• Addressing comorbid conditions (anxiety, depression, migraines, sleep disorders)
• Nutritional supplements (coenzyme Q10 and riboflavin) may be beneficial 2

Common Pitfalls to Avoid

• Delaying treatment (early intervention is critical)
• Overusing opioids
• Ignoring comorbidities
• Misdiagnosing as CHS
• Inadequate hydration 2

Prognosis

CVS can begin in childhood or adulthood, with age of onset ranging from 2 to 49 years. The disorder can persist for decades, with some patients experiencing a worsening trajectory characterized by increased episode length and frequency. However, the prognosis is favorable in the majority of patients with appropriate management 2, 3.