What is the difference between a migraine aura and a stroke?

Distinguishing Migraine Aura from Stroke

The key differentiating feature is temporal progression: migraine aura symptoms spread gradually over ≥5 minutes and occur in succession, whereas stroke symptoms have sudden, simultaneous onset. 1

Critical Distinguishing Features

Symptom Onset Pattern (Most Important)

• Migraine aura: Symptoms develop gradually, spreading over at least 5 minutes, with individual symptoms occurring one after another in succession 1
• Stroke: Symptoms appear suddenly and simultaneously, reaching maximum intensity within seconds to minutes 1
• This temporal distinction is the most reliable clinical differentiator, though overlap exists in 22-54% of cases 2, 3

Symptom Quality

• Migraine aura: Typically produces positive irritative symptoms (visual scintillations, zigzag lines, tingling sensations that spread) 1
• Stroke: Typically produces negative symptoms (sudden vision loss, numbness, weakness) 1
• However, 46% of stroke patients report positive visual symptoms and 54% report positive sensory symptoms, making this less reliable than temporal pattern 2

Vascular Territory Distribution

• Migraine aura: Hypoperfusion affects multiple vascular territories simultaneously, not respecting arterial boundaries 3
• Stroke: Perfusion deficit typically confined to a single vascular territory 3
• On perfusion imaging, migraine shows only moderate TTP increase (ratio 1.09 vs 1.47 in stroke, p<0.001) 3

Red Flags Suggesting Stroke Rather Than Typical Aura

Historical Features

• New focal neurological symptoms never experienced before (76% of strokes vs 25% of unusual auras) 4
• Change in the first symptom from patient's typical aura pattern (59% of strokes vs 8% of unusual auras) 4
• Absence of headache following neurological symptoms (40% of strokes vs 20% of unusual auras in migraine patients) 4
• Symptoms lasting >60 minutes without progression to headache 1

Physical Examination Findings

• Persistent visual field defects, ataxia, or weakness on examination strongly suggest stroke 4
• Normal examination occurs in approximately 50% of both stroke and unusual aura presentations, limiting its utility 4
• Any objective neurological deficit persisting beyond the typical aura duration (>60 minutes) warrants stroke evaluation 1

High-Risk Clinical Scenarios Requiring Immediate Stroke Workup

Patient Demographics

• Age >45 years, particularly in women with migraine with aura (stroke RR 3.65) 1
• Male patients presenting with aura-like symptoms (migraine with aura is less common in men) 1

Vascular Risk Factors Present

• Current smoking (catastrophically increases stroke risk: RR 9.03 when combined with migraine and estrogen) 1, 5
• Oral contraceptive use in women with migraine with aura (stroke RR 7.02) 1, 5
• High migraine frequency (>weekly attacks with aura: stroke HR 4.25) 1

Atypical Symptom Patterns

• Sudden onset without gradual spread 1
• Symptoms confined to single vascular territory 3
• Motor weakness as first or only symptom 1
• Absence of typical migraine features (no headache, nausea, photophobia) 1

Diagnostic Approach Algorithm

Immediate Assessment

• Document symptom onset timing: Gradual (≥5 min spread) favors migraine; sudden favors stroke 1
• Compare to patient's typical aura: Any deviation in first symptom, duration, or associated features increases stroke probability 4
• Perform focused neurological examination: Persistent objective deficits mandate stroke workup 4

Imaging Considerations

• MRI with perfusion imaging is the gold standard when diagnosis is uncertain 3
• Migraine shows multi-territorial hypoperfusion with modest TTP prolongation 3
• Stroke shows single-territory deficit with marked TTP/MTT elevation (TTP ratio >1.4 suggests stroke) 3
• Many migraineurs have chronic white matter lesions and infarct-like lesions (OR 1.4), particularly in cerebellum, which should not be confused with acute stroke 1, 5

Common Pitfalls to Avoid

• Do not rely solely on positive vs negative symptoms: 46-54% of stroke patients report positive symptoms mimicking aura 2
• Do not dismiss symptoms in known migraineurs: 22% of stroke patients experience migraine-like symptom onset 2
• Do not assume headache presence excludes stroke: 60% of strokes in migraine patients are accompanied by headache 4
• Do not overlook rare genetic causes: Consider CADASIL, MELAS, or familial hemiplegic migraine in young patients with recurrent events 1, 6

Special Populations Requiring Lower Threshold for Stroke Evaluation

• Women with migraine with aura taking estrogen-containing contraceptives (absolute contraindication per AHA/ASA guidelines) 1, 5
• Patients using triptans or ergots during prolonged aura (theoretical vasoconstrictor risk) 1, 6
• Children with hemiplegic or basilar migraine (higher stroke risk) 1
• Patients with known hypercoagulable states (OR 6.81 for stroke in migraine with aura patients <50 years) 5