What could be causing an adolescent patient to experience periodic nocturnal vomiting every 2-4 weeks?

Periodic Nocturnal Vomiting in Adolescents

The most likely diagnosis for an adolescent experiencing isolated vomiting episodes once every 2-4 weeks in the middle of the night is cyclic vomiting syndrome (CVS), a functional disorder strongly associated with migraine headaches that typically presents in childhood and may persist into adolescence. 1, 2

Understanding Cyclic Vomiting Syndrome

CVS is characterized by stereotypical episodes of rapid-onset, intense vomiting separated by weeks to months of complete wellness, with episodes commonly beginning during the night or early morning hours. 1, 2 The disorder typically presents between ages 3-7 years but can persist into adolescence and adulthood. 2

Key Clinical Features to Confirm

• Stereotypic pattern: Episodes should be remarkably similar in timing, duration, and associated symptoms within the same patient 1
• Rapid onset: Vomiting begins suddenly, often waking the patient from sleep 1
• Associated symptoms: Look for pallor, lethargy, anorexia, nausea, retching, and abdominal pain during episodes 1
• Complete wellness between episodes: This interval health is essential for diagnosis 1, 2
• Identifiable triggers: Physical or psychological stresses often precipitate episodes 1

Critical Migraine Association

There is a strong association with migraine headaches, both in the patient and particularly in the mother, suggesting CVS may represent a mitochondriopathy or migraine variant. 2 Ask specifically about:

• Personal or family history of migraines 2
• Headaches accompanying the vomiting episodes 1

Essential Red Flags Requiring Urgent Evaluation

Before accepting a CVS diagnosis, you must exclude life-threatening conditions, particularly if any of these features are present:

Bilious Vomiting

• Bilious (green) vomit indicates obstruction distal to the ampulla of Vater and represents a surgical emergency until proven otherwise 3, 4
• In this age group, consider intussusception or internal hernia 3
• Requires immediate abdominal radiograph followed by upper GI contrast series if obstruction suspected 4

Neurological Warning Signs

• Altered mental status, severe headache, focal neurological deficits, or visual changes suggest increased intracranial pressure from mass lesion, Chiari malformation, or demyelinating disease 5
• Nocturnal vomiting with neurological symptoms warrants brain MRI, as rare conditions like juvenile Alexander disease can present with recurrent night-time vomiting 6
• If vomiting does not bring relief or is accompanied by neurological symptoms, strongly consider CNS pathology 5

Metabolic/Endocrine Concerns

• Excessive thirst or polyuria suggests diabetes mellitus or diabetes insipidus 7
• Weight loss or growth failure may indicate metabolic disorders, mitochondrial disease, or fatty acid/organic acid disorders 5, 6

Diagnostic Workup

Initial Laboratory Evaluation

By definition, CVS is an idiopathic diagnosis of exclusion requiring appropriate testing: 1, 8

• Serum electrolytes, renal function, liver function to exclude metabolic causes 8
• Blood glucose and HbA1c to rule out diabetes 7
• Thyroid function tests to exclude thyroid disorders 7
• Urinalysis to assess for renal pathology 7
• Urine organic acids if metabolic disorder suspected 5

Imaging Considerations

• Brain MRI is indicated if there are any neurological symptoms, signs of increased intracranial pressure, or atypical features 5, 6
• Abdominal imaging only if bilious vomiting or concern for structural GI pathology 3, 4
• Upper GI endoscopy may be considered if symptoms suggest peptic disease, but is not routine 8

Additional Screening

• Screen for cannabinoid use in adolescents, as cannabinoid hyperemesis syndrome mimics CVS 5
• Assess for autonomic dysfunction given the association with sympathetic nervous system involvement 2

Management Approach

Acute Episode ("Abortive") Treatment

When an episode begins: 2

• Dark, quiet environment to minimize sensory stimulation 2
• IV hydration for fluid replacement 2
• Ondansetron 0.15-0.2 mg/kg (maximum 4 mg) IV/oral 8, 2
• Sumatriptan (given migraine association) 2
• Lorazepam or other benzodiazepines for severe episodes 2

Prophylactic Treatment

To prevent future episodes: 2

• Cyproheptadine (first-line in younger patients) 2
• Propranolol (particularly if migraine history) 2
• Amitriptyline (for older adolescents) 2
• Trigger avoidance once identified 2

Common Pitfalls to Avoid

• Do not assume CVS without excluding serious pathology first, particularly neurological and surgical causes 1, 5
• Do not dismiss bilious vomiting—this changes the entire differential to surgical emergencies 3, 4
• Do not overlook the family history of migraines, as this strongly supports CVS diagnosis 2
• Do not forget to ask about cannabis use in adolescents, as this is an increasingly common mimic 5
• Do not delay brain imaging if neurological symptoms are present, even if subtle 5, 6

Prognosis

CVS typically resolves over time with many children outgrowing it, though some may develop other functional disorders like irritable bowel syndrome or migraine headaches in adulthood. 2 No mortality has been directly attributed to CVS. 2