Migraine
Migraine
What You'll Learn
- ICHD-3 without aura: ≥5 attacks, 4–72 h, 2 of 4 headache features + 1 of 2 associated symptoms
- Aura timing: gradual spread ≥5 min; each non-motor aura symptom usually lasts 5–60 min; motor aura in hemiplegic migraine may last up to 72 h; followed by headache within 60 min
- CSD: cortical spreading depression (3–5 mm/min) — aura is cortical, NOT vascular
- Hemiplegic migraine genetics: FHM1 = CACNA1A (most common), FHM2 = ATP1A2 (Na+/K+-ATPase α2 subunit), FHM3 = SCN1A
- Triptan window: 5-HT1B/1D agonists most effective within 2 h of onset; contraindicated in cardiovascular disease
- CGRP pathway: gepants (acute) + mAbs (preventive) — non-vasoconstrictive option when triptans are contraindicated by CAD, stroke, PVD, or hemiplegic/brainstem aura migraine; monitor for new/worsening HTN and Raynaud phenomenon per labeling (not risk-free in uncontrolled HTN)
- MOH threshold: triptans/ergots/opioids/combination ≥10 d/month; simple analgesics ≥15 d/month
HighYield Pearls
- ICHD-3 without aura: ≥5 attacks, 4–72 h untreated, ≥2 of (unilateral, pulsating, moderate/severe, aggravated by routine activity) + ≥1 of (N/V, photo/phonophobia)
- ICHD-3 with aura: ≥2 attacks with ≥1 reversible aura (visual, sensory, language, motor, brainstem, retinal); each non-motor aura symptom usually lasts 5–60 min (motor aura in hemiplegic migraine may last up to 72 h); headache within 60 min
- Chronic migraine: ≥15 headache days/mo × ≥3 mo with ≥8 days meeting migraine criteria
- Hemiplegic migraine genetics: FHM1 = CACNA1A, FHM2 = ATP1A2, FHM3 = SCN1A — AVOID triptans (use gepants/ditans/NSAIDs)
- Status migrainosus: >72 h disabling migraine → IV fluids, antiemetic, ketorolac, magnesium, valproate, DHE, occipital nerve block; AVOID opioids
- MOH: ≥10 d/mo triptans/ergots/opioids OR ≥15 d/mo simple analgesics → withdraw + bridge
- Triptan contraindications: CAD, uncontrolled HTN, stroke, hemiplegic migraine / migraine with brainstem aura
- Gepants vs ditans: gepants (rimegepant, ubrogepant, atogepant, zavegepant) = CGRP receptor antagonists, non-vasoconstrictive when triptans are contraindicated (monitor for new/worsening HTN + Raynaud per labeling); ditan (lasmiditan) = 5-HT1F agonist with CNS impairment, Schedule V, mandatory 8 h driving restriction
- CGRP mAbs (prevention): erenumab, fremanezumab, galcanezumab, eptinezumab
- Botox (onabotulinumtoxinA): CHRONIC migraine only (PREEMPT protocol 155–195 U, 31–39 sites, q12wk) — NOT episodic
- Prevention thresholds: ≥4 migraine days/mo or significant disability → propranolol/metoprolol/timolol, topiramate, valproate, amitriptyline, venlafaxine, atogepant/rimegepant
- Pregnancy: acetaminophen +/- metoclopramide is the usual first-line acute approach; AVOID topiramate (cleft lip) + valproate (teratogen); AVOID NSAIDs at ≥20 weeks gestation unless specifically indicated and supervised (FDA 2020), especially at ≥30 weeks (ductus arteriosus closure risk)
- SNOOP red flags: Systemic, Neurologic deficit, Onset thunderclap, Older >50, Positional/Progressive/Pattern change → image (MRI ± MRA/MRV)
🔍 Quick ReferenceClinical · Imaging / red flags · Treatment / pharmacology
Clinical phenotype
- Throbbing/pulsating unilateral pain + N/V + photo/phonophobia → Migraine
- Scintillating scotoma, fortification spectra, zigzag expanding from center → Visual aura
- Cheiro-oral sensory march → Sensory aura
- Prodrome: yawning, cravings, mood changes → Migraine prodrome
- Alice in Wonderland syndrome (size/shape distortion) → Rare migraine aura
- Allodynia / cutaneous sensitization → Central sensitization in migraine
- Dizziness + migraine features → Vestibular migraine
- Monocular visual loss with migraine → Retinal migraine
- Motor aura → Hemiplegic migraine
- Vertigo, dysarthria, diplopia, tinnitus, ataxia, ↓ consciousness → Migraine with brainstem aura (formerly "basilar migraine")
- Cyclic vomiting, abdominal migraine, benign paroxysmal vertigo → Childhood migraine variants
- >72 h disabling migraine → Status migrainosus
Imaging / red flags
- SNOOP red flags → MRI ± MRA/MRV workup
- Nonspecific white matter hyperintensities (more with aura) → Migraine brain MRI
- Anterior temporal pole WM + lacunes, AD inheritance → CADASIL
- Stroke-like episodes + lactic acidosis → MELAS
- Focal pulsatile headache → AVM
- Thunderclap + segmental vasoconstriction → RCVS
- Vasogenic edema parieto-occipital → PRES
- Prolonged aura >60 min, motor/brainstem aura, age >50 onset → Image to exclude mimics
Treatment / pharmacology pearls
- Sumatriptan SC 6 mg → Fastest acute migraine + cluster onset
- Rimegepant / ubrogepant (gepants) → CGRP receptor antagonists; non-vasoconstrictive when triptans contraindicated (CAD/stroke/PVD/hemiplegic/brainstem aura) — monitor for new/worsening HTN and Raynaud per labeling
- Rimegepant every other day → Also approved for prevention
- Lasmiditan (ditan) → 5HT1F agonist, no vasoconstriction, 8 h driving restriction
- Erenumab / fremanezumab / galcanezumab / eptinezumab → CGRP mAbs for prevention
- OnabotulinumtoxinA (PREEMPT 155–195 U, 31–39 sites, q12wk) → Chronic migraine only
- Topiramate → Prevention; cleft lip in pregnancy, kidney stones, cognitive slowing
- Propranolol / metoprolol / timolol → β-blocker prevention
- Amitriptyline / venlafaxine → Adjunct prevention
- Atogepant / rimegepant → Oral gepants for prevention
- Riboflavin 400 mg, magnesium 400–600 mg, CoQ10 → Nutraceutical prevention
- IV DHE, magnesium, valproate, ketorolac, antiemetic → Status migrainosus bundle
- AVOID triptans → CAD, uncontrolled HTN, stroke, hemiplegic migraine / migraine with brainstem aura
- AVOID opioids / butalbital → MOH and bounce-back headache
- Acetaminophen first-line → Pregnancy migraine
ICHD-3 Diagnostic Criteria
Migraine Without Aura (1.1)
- A. ≥5 attacks fulfilling B–D
- B. Duration 4–72 h (untreated or unsuccessfully treated)
- C. ≥2 of 4: unilateral, pulsating, moderate-severe, aggravated by routine physical activity
- D. During headache, ≥1 of: (a) nausea and/or vomiting, OR (b) photophobia AND phonophobia (both required together as a single criterion — not all of D required)
- E. Not better accounted for by another diagnosis
Migraine With Aura (1.2)
- A. ≥2 attacks fulfilling B–C
- B. ≥1 fully reversible aura symptom (visual, sensory, speech/language, motor, brainstem, retinal)
- C. ≥3 of 6: gradual spread ≥5 min, 2+ symptoms in succession, each non-motor symptom lasts 5–60 min (motor aura in hemiplegic migraine may last up to 72 h), ≥1 unilateral, ≥1 positive symptom, accompanied/followed within 60 min by headache
Key Diagnostic Thresholds
| Feature | Without Aura (1.1) | With Aura (1.2) |
|---|---|---|
| Minimum attacks | 5 | 2 |
| Duration | 4–72 h | Each non-motor aura symptom 5–60 min (motor aura in hemiplegic migraine up to 72 h) |
| Headache features required | ≥2 of 4 | Not required |
| Associated symptoms | ≥1 of 2 | Not required |
| Aura characteristics | N/A | ≥3 of 6 |
💎 Board Pearl
- Without aura requires 5 attacks; with aura requires only 2 — classic board trap
- Photophobia and phonophobia count as a single criterion — both must be present together
Aura Types & Pathophysiology
Aura Subtypes
| Type | Frequency | Features |
|---|---|---|
| Visual | ~90% | Scintillating scotoma (fortification spectra), photopsia; binocular |
| Sensory | ~30% | Paresthesias spreading hand → arm → face; cheiro-oral distribution |
| Speech/language | ~10% | Dysphasia (expressive > receptive) |
| Motor | Rare | Hemiparesis; only in hemiplegic migraine |
| Brainstem | Rare | Dysarthria, vertigo, tinnitus, diplopia, ataxia, ↓ consciousness |
| Retinal | Very rare | Monocular visual symptoms |
Cortical Spreading Depression (CSD)
- Wave of neuronal/glial depolarization propagating at 3–5 mm/min across cortex
- Brief excitation → prolonged cortical suppression → transient oligemia
- Follows gray matter, respects sulcal boundaries; explains gradual aura march
- CSD activates trigeminovascular afferents → CGRP release → neurogenic inflammation
Trigeminovascular System
- Trigeminal ganglion → perivascular C-fibers → CGRP/substance P release → neurogenic inflammation
- Relay: trigeminal nucleus caudalis → thalamus (VPM) → cortex
- Peripheral sensitization → central sensitization (cutaneous allodynia) → reduced treatment efficacy
💎 Board Pearl
- Aura is a cortical phenomenon (CSD), NOT vascular — favorite board question
- CSD velocity (3–5 mm/min) matches gradual aura spread; seizure propagation is much faster
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