What are the diagnostic criteria for migraine (including with aura) and when is neuroimaging required?

Diagnosing Migraine: ICHD-3 Criteria and Neuroimaging Indications

Migraine diagnosis is made clinically using ICHD-3 criteria without neuroimaging, unless red flags are present on history or examination. 1, 2

Diagnostic Criteria for Migraine Without Aura

You need at least 5 lifetime attacks meeting all of the following 1, 3:

Duration: 4-72 hours when untreated (2-72 hours in children/adolescents <18 years) 1

At least 2 of these pain characteristics:

• Unilateral location (though ~40% report bilateral pain) 1
• Pulsating quality 1
• Moderate to severe intensity 1
• Aggravation by or avoidance of routine physical activity 1

At least 1 of these associated symptoms:

• Nausea and/or vomiting 1
• Both photophobia AND phonophobia 1

A practical screening mnemonic is POUND (Pulsating, 4-72 hOurs, Unilateral, Nausea, Disabling): if 4 of 5 criteria are met, the likelihood ratio for migraine is 24; if 3 are met, LR is 3.5 4

Diagnostic Criteria for Migraine With Aura

You need at least 2 lifetime attacks with the following 1, 2:

One or more fully reversible aura symptoms:

• Visual (most common, >90% of cases—classically fortification spectra) 1
• Sensory (31% of cases—unilateral paresthesia spreading gradually) 1
• Speech/language 1
• Motor 1
• Brainstem 1
• Retinal 1

At least 3 of these 6 characteristics:

• At least 1 aura symptom spreads gradually over ≥5 minutes 1
• Two or more aura symptoms occur in succession 1
• Each individual aura symptom lasts 5-60 minutes 1
• At least 1 aura symptom is unilateral 1
• At least 1 aura symptom is positive (e.g., scintillations, pins and needles) 1
• Aura is accompanied by or followed within 60 minutes by headache 1

Important caveat: Motor symptoms may last up to 72 hours, and when multiple symptoms occur, the acceptable maximum duration is multiplied (e.g., 3 symptoms = 3 × 60 minutes) 1

Clinical Clues Supporting Migraine Diagnosis

Onset typically at or around puberty 1, 3

Family history of migraine strengthens the diagnosis due to strong genetic component 1, 3

Prodromal symptoms before pain onset: depressed mood, yawning, fatigue, food cravings 1

Postdromal symptoms lasting up to 48 hours after headache resolution: tiredness, concentration difficulties, neck stiffness 1

Use a headache diary to document frequency, duration, character, triggers, and medication use—this reduces recall bias and increases diagnostic accuracy 3, 5

When Neuroimaging Is NOT Required

Neuroimaging is not routinely indicated when 1, 3:

• The patient meets ICHD-3 criteria for migraine 1, 2
• Neurological examination is completely normal 3
• No red flags are present 1, 3

Even after failed physical therapy or other treatments, neuroimaging remains unnecessary if the neurological exam is normal and no red flags have emerged 3

The rate of finding serious intracranial pathology in migraine patients with normal neurological exams is only 0.2%, which is no higher than the 0.4% rate in asymptomatic volunteers 3

Red Flags Requiring Neuroimaging

Obtain MRI brain with and without contrast (preferred modality) when any of these are present 3, 4:

Acute/emergent red flags:

• Thunderclap headache ("worst headache of life") 3
• Altered consciousness, memory, or personality 3
• Witnessed loss of consciousness 3
• Neck stiffness or limited neck flexion with unexplained fever (meningitis) 3
• Focal neurological symptoms or abnormal neurological examination findings 3, 4

Subacute red flags:

• New-onset headache after age 50 3, 4
• Progressive worsening headache over weeks to months 3
• Headache awakening patient from sleep 3
• Headache worsened by Valsalva, cough, or exertion 3, 4
• Atypical aura (focal neurological symptoms or duration >60 minutes) 3
• Recent head or neck trauma 3

Use non-contrast CT head only if presenting <6 hours from acute severe headache onset (sensitivity 95% on day 0 for subarachnoid hemorrhage) 3

Specific clinical features predicting intracranial abnormality on pooled analysis: cluster-type headache (LR 10.7), abnormal neurological exam (LR 5.3), undefined headache type (LR 3.8), headache with aura (LR 3.2), aggravation by exertion/Valsalva (LR 2.3), and vomiting (LR 1.8) 4

Distinguishing Chronic Migraine and Medication-Overuse Headache

Chronic migraine: ≥15 headache days/month for >3 months, with ≥8 days meeting migraine criteria 3

Medication-overuse headache: ≥15 headache days/month with regular overuse of non-opioid analgesics ≥15 days/month OR other acute medications ≥10 days/month for >3 months 3, 2

These conditions require different management strategies and should be systematically excluded when evaluating headache patterns 3, 2