Migraine

Overview

Migraine unfolds across four phases - not every patient experiences all four.

•Prodrome - hours before: mood change, yawning, food cravings

•Aura (migraine with aura only) - visual fortification spectra / scotoma, sensory march, dysphasia; builds over 5-60 min; caused by cortical spreading depression (CSD)

•Headache - unilateral, throbbing, moderate-severe, worsened by activity, nausea/vomiting, photophobia, phonophobia; 4-72 hours

•Postdrome - fatigue, cognitive slowing after headache resolves

⚠️

COCP is contraindicated in migraine with aura due to synergistically increased stroke risk.

Investigations

•Migraine is a clinical diagnosis - no investigation confirms it

•Headache diary - first-line tool; records frequency, duration, triggers, menstrual relationship, medication use

•MRI brain - if red flags, atypical features, or first/worst headache; not routine

•CT head + LP - urgent if thunderclap headache to exclude subarachnoid haemorrhage; LP after 12 hours if CT negative (xanthochromia)

Differential Diagnosis

Key differentials

Condition	Distinguishing features
Tension-type headache	Bilateral, pressing/tightening, mild-moderate, not aggravated by activity, no vomiting
Cluster headache	Strictly unilateral orbital, excruciating, 15-180 min, autonomic features (lacrimation, ptosis), restlessness
SAH	Thunderclap onset, meningism - life-threatening emergency
Medication overuse headache	Daily/near-daily headache, acute analgesia used ≥10-15 days/month for >3 months
IIH	Obese young women, positional headache, pulsatile tinnitus, papilloedema

Management

Treat early - at onset of headache while pain is still mild; delayed treatment significantly reduces efficacy.

•General measures: headache diary, trigger avoidance, regular sleep, regular meals, adequate hydration, limit caffeine

•Acute - mild to moderate: paracetamol 1 g orally, or aspirin 900 mg orally, or ibuprofen 400 mg orally

•Acute - moderate to severe (first-line triptan): sumatriptan 50-100 mg orally (or 6 mg SC / 20 mg nasal spray for rapid effect) - selective 5-HT1B/1D agonist; take at headache onset, NOT during aura

•Anti-emetic (add to all acute regimens): metoclopramide 10 mg orally/IM or prochlorperazine 3-6 mg buccal - improves gastric motility and analgesic absorption (gastric stasis delays absorption during attacks)

•Second-line acute: alternative triptan (zolmitriptan, rizatriptan, eletriptan) if sumatriptan fails; or sumatriptan + naproxen combination

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Triptans are contraindicated in: ischaemic heart disease, previous stroke/TIA, uncontrolled hypertension, hemiplegic or brainstem aura migraine, and pregnancy (relative). Never give during the aura phase.

Prophylaxis

Indicated when ≥4 attacks/month, prolonged/disabling attacks despite adequate acute therapy, or medication overuse. Goal: ≥50% reduction in attack frequency.

•First-line: propranolol 40-120 mg daily - most evidence; avoid in asthma, Raynaud's, depression

•First-line: topiramate 25-100 mg daily - teratogenic; contraindicated without effective contraception (pregnancy prevention programme required)

•First-line: amitriptyline 10-75 mg at night - useful if co-morbid depression or tension-type headache

•Chronic migraine (≥15 headache days/month, failed ≥3 prophylactics): botulinum toxin type A injections every 12 weeks (NICE approved)

•Anti-CGRP monoclonal antibodies (erenumab, fremanezumab) - NICE approved for chronic/high-frequency episodic migraine after other prophylactics have failed

•Menstrual migraine: frovatriptan (long half-life) taken perimenstrually as mini-prophylaxis

•Valproate - effective but highly teratogenic; absolutely avoid in women of childbearing potential

Complications

•Medication overuse headache (MOH) - most common complication; acute analgesia (including triptans) used ≥10-15 days/month for >3 months; treatment: gradual withdrawal (worsens initially before improving)

•Status migrainosus - attack >72 hours; may require admission for IV hydration, dexamethasone, IV prochlorperazine

•Migrainous infarction - rare; ischaemic stroke during migraine with aura, aura does not fully resolve

💡

In pregnancy, most women experience improvement in migraine frequency and severity, particularly in the second and third trimesters, due to stable oestrogen levels.

Red Flags (SNOOP)

•Systemic features - fever, weight loss, immunosuppression

•Neurological signs - focal deficits, altered consciousness, papilloedema

•Onset - thunderclap / 'worst ever' headache

•Older age - new headache type >50 years

•Progressive - worsening over weeks