Abdominal Migraine

Abdominal migraine is a childhood disorder of recurrent, episodic, moderate to severe midline or periumbilical abdominal pain lasting 2 to 72 hours, with at least 2 of anorexia, nausea, vomiting and pallor, and normal health between episodes. It is a migraine equivalent, and many children later develop migraine headache.

The prevalence is about 2 to 4% of school age children, with a range of 0.2 to 9% in reports. The peak age is 7 years, with onset between 3 and 10, and girls are slightly more affected.

Diagnostic criteria. At least 5 attacks, pain that is dull or just sore with moderate to severe intensity, and no other cause after assessment. Attacks are stereotyped and similar in each child.

Course. Episodes settle in most by adolescence, but 60 to 70% go on to have migraine headache. A family history of migraine is common.

Pathophysiology.

Sensitisation of the trigeminovascular system and the enteric nervous system through the gut brain axis, with abnormal serotonin and calcitonin gene related peptide signalling, is proposed.

Triggers (stress, sleep loss, fasting, foods, travel) lower the threshold for attacks.

• Sudden periumbilical or diffuse abdominal pain of moderate to severe intensity, lasting 2 to 72 hours.
• Pallor, nausea, vomiting and anorexia; sometimes headache, photophobia and flushing.
• Asymptomatic between episodes; normal growth and examination.
• Often relief with sleep in a dark room.

Red flags.

• Weight loss, faltering growth, blood in stool or vomit, or bilious vomiting.
• Pain that is localised, persistent or nocturnal, or with fever, jaundice or urinary symptoms.
• Constant pain between attacks, or abnormal abdominal examination.

• Clinical diagnosis by ICHD-3 after normal examination and growth.
• Targeted investigations to exclude other causes: urinalysis, full blood count, CRP, coeliac screen, stool studies, and abdominal ultrasound when needed.
• Imaging or endoscopy only for red flags; assessment for constipation, lactose intolerance and anxiety.
• Headache diary and family history; screening for school stress or anxiety.

Differential diagnosis. Functional abdominal pain, cyclic vomiting syndrome, constipation, coeliac disease, inflammatory bowel disease, urinary tract infection, pelviureteric obstruction, malrotation, peptic disease, porphyria and familial Mediterranean fever.

• Explain the diagnosis and identify triggers; encourage regular meals, hydration, sleep and exercise; manage anxiety and stress.
• Acute treatment: rest in a dark, quiet room and early simple analgesia.
• Paracetamol 15 mg/kg orally every 4 to 6 hours as needed. Maximum 4 doses in 24 hours (60 mg/kg daily, up to 4 g). Monitor total daily dose and liver function with prolonged use. Reduce dose in hepatic impairment; extend the interval in renal impairment (eGFR under 30).
• Ibuprofen 10 mg/kg orally every 8 hours as needed, with food. Maximum 400 mg for each dose and 30 mg/kg daily. Monitor renal function, hydration and gastrointestinal symptoms. Avoid with dehydration, renal impairment, peptic ulcer, asthma sensitive to NSAIDs and under 3 months of age.
• Prevention for frequent, long or disabling attacks (more than 1 or 2 each month): cyproheptadine 0.25 to 0.5 mg/kg orally daily in 2 or 3 divided doses (maximum 12 mg daily for age 2 to 6 years and 16 mg daily for age 7 to 14 years), for 3 months, then review. Monitor sedation, weight gain and appetite. Avoid in glaucoma, urinary retention and with monoamine oxidase inhibitors; reduce dose in hepatic and renal impairment; avoid in breastfeeding.
• Cognitive behavioural therapy and relaxation for stress related triggers.
• Avoid unnecessary investigations, and keep the child in school.

Monitoring. Review at 4 to 6 weeks and 3 months with a pain and attack diary; reassess growth.

Referral and escalation. Paediatric gastroenterology or neurology for red flags, prolonged illness, or failed prevention.

Special groups. Adolescents: expect progression to migraine headache; review contraception choices later.