Migraine — Causes, Aura, Triggers & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Migraine is a complex primary neurological disorder characterised by recurrent attacks of moderate-to-severe, typically unilateral, pulsating headache lasting 4-72 hours, associated with nausea, vomiting, photophobia, and phonophobia. It is far more than a 'bad headache' — migraine is the second leading cause of years lived with disability globally (after low back pain), affecting approximately 1 billion people. It predominantly affects women (3:1 ratio — driven by hormonal factors), with peak prevalence between ages 25-55. Migraine with aura (MWA) affects 25-30% of patients — an aura is a transient reversible neurological disturbance (typically visual) preceding or accompanying the headache. Chronic migraine — 15 or more headache days per month for 3 months, with at least 8 meeting migraine criteria — affects approximately 2% of the global population and causes severe disability. The underlying pathophysiology involves cortical spreading depression (CSD), trigeminovascular activation, CGRP (calcitonin gene-related peptide) release, and central sensitisation.

Migraine has a strong genetic component — heritability estimated at 40-65%; family history in 80% of patients. Identified gene variants affect ion channel and glutamate receptor function. The trigeminovascular hypothesis: CSD triggers release of inflammatory neuropeptides (CGRP, substance P) from trigeminal nerve terminals surrounding meningeal blood vessels, causing neurogenic inflammation and activating the trigeminocervical complex — generating head pain. Common identifiable triggers (vary by individual): hormonal changes — oestrogen fluctuation (menstruation — 'menstrual migraine' affects 60% of women with migraine; oral contraceptives; perimenopause); sleep disruption (too much or too little); stress (and stress let-down after stressful periods); skipping meals and dehydration; alcohol (particularly red wine, beer); caffeine withdrawal; strong sensory stimuli (bright lights, strong smells, loud noise); weather changes (barometric pressure shifts); and specific foods (aged cheese, processed meats containing nitrates, MSG). Comorbidities associated with migraine: depression, anxiety, epilepsy, restless legs syndrome, patent foramen ovale (PFO), and cardiovascular disease (especially in MWA).

Migraine typically evolves in phases. Prodrome (24-48 hours before headache): mood changes (depression, irritability, or euphoria), food cravings, yawning, cognitive slowing, neck stiffness, and fatigue. Aura (30 minutes before headache — if present): visual aura is most common — gradual onset over 5-30 minutes of positive phenomena (flashing lights, zigzag lines — fortification spectra/scintillating scotoma) followed by a spreading scotoma (black spot). Sensory aura: unilateral paraesthesia (pins and needles spreading over face/hand/arm). Speech/language aura: dysphasia. Motor aura: weakness (hemiplegic migraine). By definition, aura symptoms are fully reversible, spread gradually, and last 5-60 minutes — features distinguishing aura from TIA. Headache phase: unilateral (60%) or bilateral pulsating/throbbing pain; moderate to severe intensity; significantly worsened by routine physical activity; accompanied by nausea (80%), vomiting (30%), photophobia and phonophobia (90%); duration 4-72 hours. Postdrome: fatigue, cognitive impairment ('migraine hangover'), mood changes for up to 24-48 hours after headache resolves.

Migraine is a clinical diagnosis based on ICHD-3 (International Classification of Headache Disorders 3rd edition) criteria — no investigations are required for typical presentations. Migraine without aura (ICHD-3): 5 or more attacks; headache 4-72 hours; at least 2 of: unilateral, pulsating, moderate-severe, worsened by activity; at least 1 of: nausea/vomiting, photophobia + phonophobia. Migraine with aura: one or more fully reversible aura symptoms with at least 2 of: spreading over 5+ minutes, lasting 5-60 minutes, unilateral, preceded or accompanied by headache. Brain MRI with contrast is indicated for: atypical features; first or worst headache of life; progressive neurological symptoms; thunderclap onset (exclude SAH); aura symptoms lasting more than 60 minutes; posterior fossa symptoms; new headache in patients over 50. Headache diary assessment: frequency, duration, severity (VAS), triggers, medication use — essential for treatment planning and monitoring preventive therapy response. SNOOP10 mnemonic identifies secondary headache red flags.

Acute treatment: take medication early at onset of headache (not aura) for best effect. Mild-moderate attacks: NSAIDs (ibuprofen 400-600 mg or naproxen 500 mg) ± antiemetic (metoclopramide 10 mg or prochlorperazine 10 mg — also speeds gastric emptying to enhance NSAID absorption; also has independent analgesic effect). Aspirin 900 mg + metoclopramide is an effective and cheap option. Moderate-severe attacks or NSAID failure: triptans (5-HT1B/1D agonists) — sumatriptan 50-100 mg oral, 6 mg subcutaneous (fastest onset), or 20 mg nasal spray; rizatriptan 10 mg; zolmitriptan 5 mg; most effective within first 30 minutes. Avoid ergotamine (abuse potential). Lasmiditan (5-HT1F agonist, ditan class) — effective without vasoconstriction, suitable for cardiovascular contraindications to triptans. Gepants (CGRP receptor antagonists): rimegepant 75 mg, ubrogepant — acute and preventive use; can be used daily without medication overuse headache risk. Preventive therapy (indicated when 4 or more migraine days/month, or less frequent but severely disabling attacks, or overuse of acute medications more than 10-15 days/month): First-line: beta-blockers (propranolol 40-120 mg BD, metoprolol); topiramate 25-100 mg/day (teratogenic — contraception essential); amitriptyline 10-75 mg nocte; valproate (highly effective but absolutely contraindicated in pregnancy). Second-line: CGRP monoclonal antibodies — erenumab (Aimovig), fremanezumab (Ajovy), galcanezumab (Emgality), eptinezumab (IV quarterly) — NICE-approved for chronic or episodic migraine with 4+ migraine days/month failing two preventive treatments; highly effective (50% reduction in migraine days in 50% of patients). Botulinum toxin A (Botox) injections: NICE-approved for chronic migraine (15+ days/month).

Chronic migraine — defined as 15 or more headache days per month, with at least 8 fulfilling migraine criteria — affects 2% of the population and causes severe occupational and social disability. Medication-overuse headache (MOH) develops in 30-50% of frequent migraine sufferers who use analgesics, triptans, or opioids on more than 10-15 days per month, paradoxically worsening headache frequency. Migraine with aura carries approximately double the risk of ischaemic stroke — particularly in women under 45 who smoke and take combined oral contraceptives (combined oral contraceptive use is contraindicated in migraine with aura). Depression and anxiety each affect 40-50% of people with chronic migraine. Missed workdays and reduced productivity from migraine cause significant economic impact — estimated at $36 billion annually in the USA.

Identify and manage personal triggers using a headache diary — common modifiable triggers: irregular sleep schedule (maintain consistent sleep and wake times even at weekends), meal skipping (eat regularly), dehydration (8 glasses water daily), alcohol, and caffeine excess or withdrawal. Regular aerobic exercise (3x weekly, 30-45 minutes) reduces migraine frequency by 20-30% — start gradually as vigorous exercise can initially trigger migraine. Stress management: mindfulness-based stress reduction (MBSR), biofeedback, and CBT reduce migraine frequency and disability. Avoid oral oestrogen-containing contraceptives in women with migraine with aura — increases stroke risk 6-8x (use progesterone-only pill or non-hormonal methods). Medication overuse headache (MOH — analgesic-overuse headache): developing new daily headache in patients using acute medications (triptans or opioids more than 10 days/month; NSAIDs more than 15 days/month) — requires structured withdrawal and preventive therapy.

Go to Emergency Department immediately for: thunderclap headache — sudden onset 'worst headache of my life' reaching maximum intensity within 60 seconds (subarachnoid haemorrhage until proven otherwise); headache with fever, neck stiffness, rash, or photophobia (meningitis); headache after head trauma; headache with new progressive neurological deficit (weakness, speech difficulty, vision loss); new severe headache in anyone over 50 (consider giant cell arteritis — check ESR urgently). See your GP urgently for: first episode of aura lasting more than 60 minutes; aura with motor weakness (hemiplegic migraine); new headache pattern significantly different from usual migraine; headache waking you from sleep consistently; headache increasing in frequency or severity. Routine GP or neurology referral for: migraine more than 4 days/month for preventive therapy discussion; inadequate response to two preventive treatments (consider CGRP mAb referral).