What could be causing an 11-year-old child's monthly episodes of nausea and vomiting upon waking, exacerbated by physical activity, with no progression of symptoms over the past 10 months?

Cyclic Vomiting Syndrome

This 11-year-old child most likely has cyclic vomiting syndrome (CVS), a functional gastrointestinal disorder characterized by recurrent, stereotypic episodes of severe nausea and vomiting separated by completely symptom-free intervals. 1, 2

Clinical Features Supporting CVS Diagnosis

The presentation is classic for CVS based on several key features:

• Monthly recurrent pattern with complete symptom resolution between episodes over 10 months without progression indicates the stereotypic, episodic nature of CVS rather than structural pathology 1, 2
• Morning onset upon waking is typical, as CVS episodes characteristically begin during the night or early morning hours 3
• Exacerbation with physical activity aligns with known triggers including exercise and physical stress 1, 3
• Age of presentation at 11 years falls within the typical range, as CVS usually begins in toddlers but can persist through adolescence 2, 3

Essential Red Flags to Exclude First

Before diagnosing CVS, you must actively exclude surgical emergencies and serious pathology:

• Bilious vomiting would indicate intestinal obstruction (including malrotation with volvulus) requiring immediate surgical evaluation 4, 5
• Blood in vomit or stool suggests GI bleeding, intussusception, or other serious pathology 4, 6
• Abdominal distension or tenderness points toward obstruction, appendicitis, or other surgical conditions 4, 6
• Neurological signs (altered mental status, headache progression, focal deficits) indicate increased intracranial pressure from tumor, hydrocephalus, or other CNS pathology 7, 6
• Poor weight gain or weight loss elevates concern from functional disorder to organic disease requiring aggressive investigation 8, 6
• Fever with toxic appearance suggests sepsis, meningitis, or appendicitis 7, 6

Critical pitfall: The absence of these red flags over 10 months makes structural or progressive disease highly unlikely, but you must document their absence explicitly. 9, 6

Diagnostic Approach

CVS is a clinical diagnosis of exclusion requiring:

• Detailed vomiting pattern history: Confirm rapid onset, rapid resolution, complete wellness between episodes, and stereotypic pattern within this individual child 1, 2
• Trigger identification: Document relationship to stress, anxiety, infection, exercise, menstruation (if applicable), or specific foods 1, 3
• Family history: Strong association with migraine in patient or family members 1, 2
• Basic exclusionary testing: Complete blood count, comprehensive metabolic panel, urinalysis to exclude metabolic disorders, renal disease, and diabetes 9, 6
• Imaging only if red flags present: Abdominal radiograph or upper GI series if any concern for obstruction; brain imaging if neurological symptoms 7, 9

Do not order routine imaging or extensive testing in the absence of red flags, as CVS diagnosis is based on clinical pattern and normal basic laboratory evaluation. 9, 1

Management Strategy

Preventive Phase (Primary Goal)

• Amitriptyline, cyproheptadine, or propranolol are first-line prophylactic agents, with 38% of patients achieving complete symptom resolution 2
• Trigger avoidance: Identify and minimize exposure to specific triggers including stress, sleep deprivation, and dietary factors 1, 3
• Stress management: Address anticipatory anxiety and psychological stressors that commonly precipitate episodes 1, 3

Acute Episode Management

• Early intervention at symptom onset improves outcomes and may abort the episode 2
• Ondansetron 0.2 mg/kg oral (maximum 4 mg) for persistent vomiting preventing oral intake 6
• Sedation and dark, quiet environment to reduce sensory stimulation 1
• IV hydration if unable to maintain oral intake 6

Monitoring and Follow-up

• Regular weight checks are essential—poor weight gain would indicate inadequate control or alternative diagnosis requiring reassessment 8, 2
• Track episode frequency, duration, and severity to assess treatment efficacy; successful treatment typically reduces emergency visits from 2.3 to 0.6 times per year 2

Prognosis

Most children with CVS improve as they mature, with many outgrowing symptoms during adolescence, though some develop migraine headaches or continue episodes into adulthood. 1, 3 Early diagnosis and prophylactic treatment significantly improve quality of life and reduce healthcare utilization. 2

The exacerbation with physical activity in this case is particularly important: While exercise is a known CVS trigger 1, ensure adequate hydration during physical activity, as dehydration can both trigger CVS episodes and increase heat-related illness risk in active children. 7