Migraine
Description
- Recurrent primary headache disorder - unilateral, pulsatile, moderate-severe, with associated nausea/photophobia/phonophobia, +/- aura
- Migraine with aura (~1/3) vs without aura (~2/3); chronic migraine = >=15 headache days/month for >3 months, >=8 of which are migrainous
Epidemiology
- F>M (~3:1), peak prevalence 25-55 years
- One of the leading causes of years lived with disability globally
- Strong genetic component (family history common)
Aetiopathogenesis
- Trigeminovascular activation with release of CGRP (calcitonin gene-related peptide) -> neurogenic inflammation, vasodilation, central sensitisation
- Cortical spreading depression underlies aura
- Triggers: sleep disruption, stress (and post-stress relaxation), fasting/missed meals, dehydration, hormonal fluctuation (menstrual migraine), alcohol, certain foods, weather change
- Medication overuse (see Natural history) perpetuates chronic migraine
Diagnosis
Clinical (ICHD-3 criteria) - diagnosis without routine imaging
- >=5 attacks lasting 4-72 hours (untreated), with >=2 of: unilateral, pulsating, moderate-severe intensity, aggravated by routine activity
- Plus >=1 of: nausea/vomiting, photophobia and phonophobia
Aura (if present)
- Fully reversible visual (commonest - scintillating scotoma, fortification spectra), sensory, speech, or motor symptoms, typically developing over >=5 minutes, each lasting 5-60 minutes, followed by headache within 60 minutes
- Hemiplegic migraine - motor aura, rare, genetic subtypes - higher-stakes diagnosis, needs specialist input
Red flags mandating imaging/further work-up ("SNOOP")
- Systemic symptoms/illness (fever, weight loss, malignancy, immunosuppression)
- Neurological signs/symptoms new or abnormal exam
- Onset sudden/thunderclap
- Older age at onset (>50)
- Pattern change (progressive, positional, precipitated by Valsalva) or Papilloedema
- Any of these -> neuroimaging (CT/MRI), do not assume migraine
Management
A. Acute treatment - stratified by severity, not step-care
- Mild-moderate: NSAID (e.g. ibuprofen, naproxen) or aspirin +/- antiemetic
- Moderate-severe: triptan (e.g. sumatriptan) as early in the attack as possible - contraindicated in cardiovascular/cerebrovascular disease and uncontrolled hypertension
- Antiemetic (metoclopramide, prochlorperazine) treats nausea and has independent analgesic effect via dopamine antagonism
- Gepants (rimegepant) - oral CGRP-receptor antagonist, effective for acute treatment without vasoconstrictive risk, useful where triptans contraindicated; not PBS-funded in Australia, out-of-pocket cost significant
- *Limit acute treatment to <=2-3 days/week* to avoid medication overuse headache
B. Preventive therapy - indicated if >=4 migraine days/month, disabling attacks, or acute treatment overuse/contraindication
- First-line oral agents: propranolol, candesartan, amitriptyline, topiramate (avoid topiramate/valproate in pregnancy potential - teratogenic)
- CGRP monoclonal antibodies (galcanezumab, fremanezumab, eptinezumab) - PBS-listed for chronic migraine after failure of standard prophylactics; as of November 2024, GPs can initiate PBS-listed biologic migraine treatment in consultation with a specialist, widening access
- Rimegepant also has evidence for prevention in episodic migraine (dosed every second day) but is not PBS-subsidised
- Botulinum toxin A - PBS-listed specifically for chronic migraine (not episodic)
C. Menstrual migraine
- Short-term perimenstrual triptan or NSAID prophylaxis around predictable timing
D. Lifestyle
- Regular sleep/meals/hydration, trigger diary, address medication overuse headache proactively (withdraw overused analgesic/triptan under supervision)
Associations
- Depression, anxiety
- Meniere disease and other vestibular disorders (clinical overlap)
- Patent foramen ovale (association with migraine with aura, causality unclear)
- Ischaemic stroke - small absolute increased risk with migraine with aura, particularly with smoking/combined oral contraceptive use (relative contraindication to combined OCP in migraine with aura)
Natural history & complications
- Episodic migraine can progress to chronic migraine, often driven by medication overuse headache (using acute agents >=10-15 days/month depending on drug class)
- Status migrainosus - attack lasting >72 hours, may need hospital-based treatment (IV fluids, antiemetics, dihydroergotamine or corticosteroid taper in refractory cases)
- Migrainous infarction - rare, aura symptoms with corresponding infarct on imaging
- Often improves with age/after menopause but can persist lifelong; pregnancy frequently improves migraine without aura
🔒
6 more sections, plus exam facts
Premium unlocks every note across every specialty, and the full exam fact library behind it.
Get premium access