Functional Nausea in Children

Functional nausea in children is defined by bothersome nausea as the predominant symptom, occurring at least twice a week, generally not related to meals, not consistently associated with vomiting; after appropriate evaluation, the nausea cannot be fully explained by another medical condition; symptoms present for at least 2 months.

• Affects children and adolescents (peak 8 to 18 years), with a female predominance in adolescents; frequently coexists with functional dyspepsia, functional abdominal pain, migraine, anxiety and depression, school avoidance, sleep problems.
• Mechanism: disordered gut brain interaction with visceral hypersensitivity, gastric dysmotility (delayed or accelerated gastric emptying, impaired accommodation), autonomic dysfunction, and central sensitisation; psychosocial stress, trauma, and family anxiety as modifiers.
• Organic causes to exclude: gastroparesis, peptic ulcer disease, Helicobacter pylori infection, coeliac disease, inflammatory bowel disease, eosinophilic oesophagitis, pancreatitis, hepatobiliary disease, urinary tract infection or renal disease, pregnancy, migraine, raised intracranial pressure, Chiari malformation, diabetes ketoacidosis, Addison disease, drugs (antibiotics, iron, NSAIDs, stimulants, oral contraceptives, chemotherapy), chronic infection, cyclic vomiting syndrome, and eating disorders.

• Persistent or recurrent nausea, often worse in the morning or with stress, associated with early satiety, bloating, abdominal discomfort, headache, dizziness, fatigue, pallor, sweating, reduced appetite, school absence, and sometimes weight loss; vomiting is infrequent.
• Ask about triggers, relation to meals, school, sleep, bowel habit, headaches, menstrual history and sexual activity in adolescents, medications, travel, diet, family history of migraine and gastrointestinal disease, psychosocial stressors, bullying, eating behaviours.
• Examination: growth chart, vital signs including postural blood pressure, abdomen (tenderness, mass), neurological examination, fundi, signs of anaemia, dehydration, goitre.
• Red flags: weight loss or growth failure, persistent vomiting (especially bilious), haematemesis, melaena, dysphagia, nocturnal symptoms that wake the child, persistent right upper or right lower quadrant pain, fever, jaundice, morning headache with vomiting, visual changes, papilloedema, neurological signs, delayed puberty, family history of inflammatory bowel disease, peptic ulcer, or coeliac disease, polydipsia and polyuria, positive pregnancy test.

• Clinical diagnosis after a focused history, examination and limited tests.
• Initial investigations: full blood count, CRP, electrolytes, urea, creatinine, glucose, liver function, amylase or lipase, coeliac serology, thyroid function, urinalysis and culture, pregnancy test (post-menarchal girls), Helicobacter pylori stool antigen or urea breath test (note it should be interpreted in the context of symptoms).
• Further tests if alarm features or non-response: abdominal ultrasound, upper endoscopy with biopsy, gastric emptying scintigraphy, brain MRI (neurological signs), faecal calprotectin.

• Explain that nausea is real and functional, caused by gut brain interaction; avoid dismissing or over investigating.
• Lifestyle: regular small meals, adequate fluids, avoid triggers (strong odours, fatty meals, caffeine, carbonated drinks), regular sleep, physical activity, and school attendance; a symptom diary.
• Psychological therapies (first line for persistent symptoms): cognitive behavioural therapy, gut directed hypnotherapy, relaxation, and breathing exercises; address anxiety, school avoidance and family responses.
• Complementary: ginger (250 mg capsules three to four times daily, or ginger tea); peppermint is avoided if reflux related.
• Drug therapy for troublesome nausea (short courses, specialist input if prolonged):
  • Cyproheptadine 0.25 to 0.5 mg/kg/day orally in two divided doses (for example 2 mg twice daily for ages 2 to 6 years; 4 mg twice daily for older children; maximum 0.5 mg/kg/day or 12 mg per day for ages 2 to 6 and 16 mg per day for ages 7 to 14); sedation, weight gain.
  • Amitriptyline 0.1 mg/kg orally at night (about 10 mg), increased every 1 to 2 weeks to 0.25 to 1 mg/kg (maximum 25 to 50 mg); baseline ECG; monitor for anticholinergic effects and mood; specialist initiation.
  • Ondansetron 0.1 to 0.15 mg/kg orally (maximum 4 mg per dose, 8 mg in older children) every 8 hours for up to 3 to 5 days for acute exacerbations; QT prolongation and constipation; not for long term use.
  • Omeprazole 1 mg/kg/day orally (maximum 20 mg) for 4 weeks when dyspeptic symptoms or epigastric pain accompany nausea; stop if no response.
  • Domperidone 250 micrograms/kg orally up to three times daily is licensed only for acute nausea and vomiting for up to 48 hours in some regions (QT risk); avoid in routine use.
  • Treat migraine (abdominal migraine): propranolol 0.5 to 1 mg/kg/day in 2 to 3 divided doses, or pizotifen 0.5 to 1.5 mg at night, with neurologist input.
  • Treat Helicobacter pylori if positive on stool antigen or biopsy and symptoms persist, with weight based eradication therapy: omeprazole 1 mg/kg/day, amoxicillin 50 mg/kg/day and clarithromycin 15 mg/kg/day, each in two divided doses for 14 days (metronidazole 20 mg/kg/day in two divided doses replaces amoxicillin in penicillin allergy).
• Nutritional support when weight is lost: dietitian, oral supplements.
• Review in 4 to 6 weeks; refer to paediatric gastroenterology for alarm features or persistent symptoms, and to child mental health services for anxiety, depression or school refusal.