What is the differential diagnosis and recommended management for an 11‑year‑old with systemic lupus erythematosus who experiences predictable monthly episodes of nausea and vomiting lasting about one day, triggered by exercise, waking in the morning, or large meals, and relieved by vomiting or rest?

Cyclic Vomiting Syndrome in an 11-Year-Old with Lupus

This clinical presentation is most consistent with cyclic vomiting syndrome (CVS), and you should initiate prophylactic amitriptyline 25 mg at bedtime, titrating to 75–150 mg nightly, while educating the patient to recognize prodromal symptoms and use abortive therapy with sumatriptan plus ondansetron at the earliest warning signs. 1

Differential Diagnosis

The predictable monthly pattern of self-limited nausea and vomiting episodes lasting one day, triggered by specific factors (exercise, waking, large meals) and relieved by vomiting or rest, strongly suggests CVS rather than lupus-related gastrointestinal manifestations. 1

Primary Consideration: Cyclic Vomiting Syndrome

• This patient meets Rome IV diagnostic criteria: stereotypical acute-onset vomiting episodes lasting <7 days, ≥3 discrete episodes in the past year (12 episodes over 12 months), separated by ≥1 week of wellness between episodes 1
• The triggers described (physical activity, waking, heavy meals) are classic CVS precipitants, with most episodes occurring in early morning hours and stress/physical exertion being triggers in 70–80% of patients 1
• CVS has been documented in patients with systemic autoimmune conditions including SLE, though it remains a distinct functional disorder 2
• The absence of headache progression argues against migraine, though 20–30% of CVS patients have personal or family history of migraine 1

Critical Exclusions in a Lupus Patient

Before confirming CVS, you must exclude lupus-specific gastrointestinal complications:

• Intestinal pseudo-obstruction (IPO): This rare but dangerous SLE complication presents with recurrent vomiting and abdominal distension, but typically shows progressive worsening rather than complete inter-episodic wellness 3
• Lupus mesenteric vasculitis: Would typically present with more severe abdominal pain, bloody diarrhea, and signs of acute abdomen 4
• Neuropsychiatric lupus: The EULAR guidelines emphasize that diagnostic work-up of neuropsychiatric manifestations in SLE patients should be similar to the general population 4

Perform basic screening to exclude structural and metabolic causes:

• Complete blood count, serum electrolytes, glucose, liver function tests, lipase, and urinalysis to identify metabolic derangements 5
• One-time esophagogastroduodenoscopy to exclude peptic ulcer disease, gastric outlet obstruction, or malignancy (especially given the lupus diagnosis) 5, 6
• Screen for cannabis use ≥4 times weekly for >1 year to differentiate cannabinoid hyperemesis syndrome from CVS 1, 5

Disease Severity Classification

This patient has moderate-severe CVS based on:

• ≥4 episodes per year (12 episodes in 12 months) 1
• Episodes lasting approximately one day each 1
• This classification mandates both prophylactic and abortive therapy 1

Management Algorithm

Step 1: Initiate Prophylactic Therapy

Start amitriptyline as first-line prophylactic agent:

• Begin with 25 mg at bedtime 1, 5
• Titrate by 10–25 mg every 2 weeks to target dose of 75–150 mg nightly (or 1–1.5 mg/kg for this 11-year-old) 1
• Obtain baseline ECG before starting therapy due to QTc prolongation risk 1, 5
• Administer at night to minimize daytime sedation and anticholinergic effects (dry mouth, blurred vision, constipation) 1
• Expected response rate is 67–75% 1, 5

If amitriptyline fails or is not tolerated, second-line options include:

• Topiramate 25 mg daily, titrating to 100–150 mg daily in divided doses (monitor electrolytes and renal function twice yearly) 1
• Levetiracetam 500 mg twice daily, titrating to 1000–2000 mg daily (monitor CBC) 1

Step 2: Educate on Abortive Therapy

The probability of aborting an episode is highest when medications are taken immediately at prodromal symptom onset. 1, 5

Teach the patient and family to recognize prodromal symptoms:

• Impending sense of doom, anxiety, panic 1
• Diaphoresis (occurs in 70–80% of CVS patients during prodrome) 1
• Mental fog, restlessness, fatigue 1
• Bowel urgency 1

Standard abortive regimen at prodrome onset:

• Sumatriptan 20 mg intranasal spray (can repeat once after 2 hours, maximum 2 doses per 24 hours) 1
• Ondansetron 8 mg sublingual every 4–6 hours during the episode 1
• Administer sumatriptan in head-forward position to optimize nasal receptor contact 1

Step 3: Lifestyle Modifications and Trigger Management

All CVS patients require:

• Regular sleep schedule, avoiding sleep deprivation 1, 5
• Avoiding prolonged fasting 1, 5
• Stress management techniques (stress triggers 70–80% of CVS episodes, including positive stressors like birthdays) 1
• Systematic identification and avoidance of individual triggers 1

Step 4: Screen and Treat Psychiatric Comorbidities

Screen for anxiety, depression, and panic disorder:

• Present in 50–60% of CVS patients 1, 5
• Treating underlying anxiety can decrease CVS episode frequency 1, 5
• Consider referral to psychology or psychiatry if comorbidities identified 5

Step 5: Monitor Lupus Activity

Ensure the patient's lupus is adequately controlled:

• New clinical manifestations (rashes, arthritis, serositis, neurological signs) should prompt evaluation for lupus flare 4
• Monitor routine laboratory tests (CBC, serum creatinine, proteinuria, urinary sediment) and immunological tests (serum C3, anti-dsDNA) 4
• If concurrent lupus flare is present, glucocorticoids alone or with immunosuppressive therapy may be indicated 4

Emergency Department Management (If Episode Occurs)

If the patient presents during an active vomiting episode:

• Place in quiet, dark room immediately to minimize sensory stimulation 1
• Aggressive IV fluid replacement with dextrose-containing fluids for rehydration and metabolic support 1, 5
• Ondansetron 8 mg IV every 4–6 hours as first-line antiemetic 1, 5
• IV ketorolac 15–30 mg every 6 hours for abdominal pain (avoid opioids, which worsen nausea and carry addiction risk) 1, 5
• Sedation with benzodiazepines in refractory cases 1

Critical Pitfalls to Avoid

• Missing the prodromal window dramatically reduces abortive therapy effectiveness—emphasize immediate medication administration at first warning sign 1
• Do not dismiss abdominal pain as excluding CVS—abdominal pain is present in most CVS attacks 1
• Do not misinterpret self-soothing behaviors (excessive water intake, seeking dark rooms) as malingering—these are characteristic coping mechanisms 1
• Avoid opioids—they exacerbate nausea and have high addiction potential in CVS patients 1, 5
• Do not perform repeated endoscopy or imaging unless new symptoms develop 5
• Monitor for QTc prolongation with both amitriptyline and ondansetron, especially given potential electrolyte abnormalities from vomiting 1, 5

Special Considerations in Lupus Patients

• IPO secondary to SLE requires immunosuppressive therapy as first-line treatment if diagnosed, and surgical intervention should be avoided 3
• Juvenile-onset SLE patients (20% of all SLE cases) tend to have earlier end-organ damage and increased need for immunosuppressive therapies 7, 6, 8
• Maintain high index of suspicion for lupus-related complications while recognizing that CVS can coexist with autoimmune conditions 2