How to elicit a medical history in a pediatric patient with cyclical vomiting syndrome?

How to Elicit History in Cyclic Vomiting Syndrome in Children

When evaluating a child for cyclic vomiting syndrome, focus your history on documenting the stereotypical pattern of episodes: at least 3 discrete vomiting episodes in the past year (with 2 in the last 6 months), each lasting less than 7 days, separated by at least 1 week of baseline health, and ask specifically about prodromal symptoms, triggers, timing patterns, and associated behaviors like hot water bathing. 1

Essential Diagnostic Questions

Episode Pattern and Characteristics

• Ask about the stereotypical nature of episodes: Each child with CVS can identify a specific order of onset and cluster of symptoms that are stereotypically associated with their episodes 1
• Document episode frequency and duration: Confirm at least 3 discrete episodes in a year, with 2 occurring in the prior 6 months, each lasting less than 7 days, and separated by at least 1 week of baseline health 1, 2
• Inquire about symptom-free intervals: Between episodes, vomiting should be absent, though milder symptoms like nausea, occasional vomiting, and dyspepsia may persist 1, 3
• Ask about timing of episodes: Most episodes tend to occur in the early morning hours, though they can present at any time of day 1

Prodromal Phase Recognition

• Screen for prodromal symptoms: Approximately 65% of patients experience prodromal symptoms lasting a median of 1 hour before vomiting onset 1
• Ask specifically about: Impending sense of doom, panic, fatigue, feeling hot or cold, mental fog, restlessness, anxiety, headache, bowel urgency, acute diarrhea or constipation, diaphoresis, flushing, or shakiness 1, 4
• Document communication difficulties: Many patients report panic and are often unable to communicate effectively during the prodromal phase 1

Emetic Phase Characteristics

• Ask about both vomiting AND retching: Clinicians often ignore retching and unremitting nausea, which are equally disabling as vomiting itself 1, 3
• Inquire about self-soothing behaviors: Patients may drink large amounts of water or stick their fingers in their throat to induce vomiting for temporary relief—do not misconstrue these as malingering, as they are specific to CVS 1
• Document hot water bathing: Ask if the child seeks hot water bathing or showering targeting the trunk or back during episodes, as approximately 48% of CVS patients who don't use cannabis find relief from this behavior 1, 4

Associated Symptoms

• Always ask about abdominal pain: Abdominal pain is present in most patients during CVS episodes and should not preclude the diagnosis 1
• Document constitutional symptoms: Fatigue, feeling hot or cold, diaphoresis, flushing 1, 4
• Ask about autonomic symptoms: Bowel urgency, acute diarrhea or constipation 1
• Screen for cognitive/affective symptoms: Mental fog, restlessness, anxiety 1

Critical Trigger Identification

Common Triggers to Ask About

• Psychological stress: Present in approximately 70-80% of patients—ask about both negative stress (death, family conflicts) AND positive events (birthdays, family reunions, vacations) 1
• Sleep deprivation: A common trigger that should be specifically addressed 1
• Physiological stressors: Acute infections, surgery 1
• Other triggers: Travel, motion sickness, hormonal fluctuations (in adolescent girls), prolonged fasting, intense exercise 1

Family and Personal History

• Migraine history: Ask about personal or family history of migraine headaches, as this is a supportive criterion and present in 20-30% of CVS patients 1, 4, 3
• Psychiatric comorbidities: Screen for anxiety, depression, and panic disorder, as these are present in 50-60% of CVS patients 4, 3

Critical Differential Diagnosis Questions

Cannabis Use Screening

• Always screen for cannabis use: Cannabis use more than 4 times weekly for more than 1 year suggests cannabinoid hyperemesis syndrome (CHS) rather than CVS 4, 3
• Note that hot water bathing is NOT pathognomonic for CHS: 48% of CVS patients who don't use cannabis also exhibit this behavior 4, 3

Red Flag Symptoms to Exclude

• Ask about bilious or bloody vomiting: These suggest surgical causes requiring immediate evaluation 5
• Screen for altered sensorium: May indicate intracranial pathology 5
• Document any progressive symptoms: Some patients develop "coalescent CVS" with progressively fewer symptom-free days 3

Severity Classification Questions

Classify disease severity to guide treatment intensity 4, 3:

• Mild CVS: Less than 4 episodes per year, each lasting less than 2 days, without ED visits or hospitalizations 1, 4
• Moderate-severe CVS: 4 or more episodes per year, lasting more than 2 days, requiring at least 1 ED visit or hospitalization 1, 4

Common Pitfalls to Avoid

• Don't overlook retching and nausea: These symptoms are equally disabling as vomiting and must be documented 1, 3
• Don't misinterpret self-soothing behaviors: Excessive water drinking or self-induced vomiting are specific to CVS and provide temporary relief, not malingering 1, 3
• Don't exclude CVS based on abdominal pain: Most CVS patients have abdominal pain during episodes 1
• Don't assume hot water bathing means CHS: This behavior occurs in nearly half of CVS patients without cannabis use 4, 3