Approach Considerations

Because no biochemical markers for cyclic vomiting syndrome (CVS) have been identified, the guidelines formulated by the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) suggest that physicians must initially look for alarming symptoms and then tailor the workup accordingly. Suspicious symptoms include the following:

• Bilious vomiting, abdominal tenderness, or severe abdominal pain
• Attacks precipitated by intercurrent illness, fasting, or a high-protein meal
• Abnormal neurologic examination findings, such as severe alteration of mental status, abnormal eye movements, papilledema, motor asymmetry, or gait abnormality (ataxia)
• Progressively worsening episodes or conversion to a continuous or chronic pattern

Depending on the presenting symptoms and signs other than vomiting, different diagnostic approaches are recommended. In addition, certain subgroups of patients are thought to be at high risk for metabolic disorders. If the following conditions are met, early referral to a metabolic specialist or neurologist should be considered:

• Presentation before the age of 2 years (with cyclic vomiting or comorbidities below)
• Vomiting episodes associated with intercurrent illnesses, prior fasting, or increased protein intake
• Any neurologic finding, such as ataxia, dystonia, or another gait disturbance; mental retardation; or seizure disorder or acute encephalopathy (including true lethargy, severe irritability, confusion, psychosis, or rapidly changing or unstable mental status)
• Laboratory findings suggestive of a metabolic disorder, such as hypoglycemia, substantial anion gap metabolic acidosis, respiratory alkalosis, or hyperammonemia

A heterogeneous group of disorders can mimic CVS, and these disorders must be excluded with systematic laboratory and radiographic testing. An analysis by Li et al identified 3 main categories to be considered in the differential diagnosis

• Gastrointestinal (GI) disorders
• Extraintestinal disorders
• Idiopathic CVS

A psychological evaluation may reveal ongoing panic, anxiety, and eating disorders, and stress management may attenuate the stress triggers.